Commit graph

1001 commits

Author SHA1 Message Date
Jens Axboe
53674ac5a9 block: add warning to blk_make_request()
Add a note about how one needs to be careful when setting up these bio
chains.

Extracted from Boaz's updated patch.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 19:52:35 +02:00
Boaz Harrosh
a411f4bbb8 block: Un-export blk_rq_append_bio
OSD was the last in-tree user of blk_rq_append_bio(). Now
that it is fixed blk_rq_append_bio is un-exported and
is only used internally by block layer.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 12:14:56 +02:00
Boaz Harrosh
79eb63e9e5 block: Add blk_make_request(), takes bio, returns a request
New block API:
given a struct bio allocates a new request. This is the parallel of
generic_make_request for BLOCK_PC commands users.

The passed bio may be a chained-bio. The bio is bounced if needed
inside the call to this member.

This is in the effort of un-exporting blk_rq_append_bio().

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
CC: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 12:14:56 +02:00
James Bottomley
3a5a39276d block: allow blk_rq_map_kern to append to requests
Use blk_rq_append_bio() internally instead of blk_rq_bio_prep()
so blk_rq_map_kern can be called multiple times, to map multiple
buffers.

This is in the effort to un-export blk_rq_append_bio()

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 12:14:55 +02:00
Tejun Heo
5f49f63178 block: set rq->resid_len to blk_rq_bytes() on issue
In commit c3a4d78c58, while introducing
rq->resid_len, the default value of residue count was changed from
full count to zero.  The conversion was done under the assumption that
when a request fails residue count wasn't defined.  However, Boaz and
James pointed out that this wasn't true and the residue count should
be preserved for failed requests too.

This patchset restores the original behavior by setting rq->resid_len
to blk_rq_bytes(rq) on request start and restoring explicit clearing
in affected drivers.  While at it, take advantage of the fact that
rq->resid_len is set to full count where applicable.

* ide-cd: rq->resid_len cleared on pc success

* mptsas: req->resid_len cleared on success

* sas_expander: rsp/req->resid_len cleared on success

* mpt2sas_transport: req->resid_len cleared on success

* ide-cd, ide-tape, mptsas, sas_host_smp, mpt2sas_transport, ub: take
  advantage of initial full count to simplify code

Boaz Harrosh spotted bug in resid_len initialization.  Fixed as
suggested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Borislav Petkov <petkovbb@googlemail.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 11:36:08 +02:00
Ingo Molnar
1079cac0f4 Merge commit 'v2.6.30-rc6' into tracing/core
Merge reason: we were on an -rc4 base, sync up to -rc6

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-18 10:15:35 +02:00
Kazuhisa Ichikawa
af498d7fa3 block: fix the bio_vec array index out-of-bounds test
Current bio_vec array index out-of-bounds test within
__end_that_request_first() does not seem correct.
It checks bio->bi_idx against bio->bi_vcnt, but the subsequent code
uses idx (which is, bio->bi_idx + next_idx) as the array index into
bio_vec array. This means that the test really make sense only at
the first iteration of !(nr_bytes >=bio->bi_size) case (when next_idx
== zero). Fix this by replacing bio->bi_idx with idx.
(This patch applies to 2.6.30-rc4.)

Signed-off-by: Kazuhisa Ichikawa <ki@epsilou.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-12 13:27:45 +02:00
FUJITA Tomonori
b1f744937f block: move completion related functions back to blk-core.c
Let's put the completion related functions back to block/blk-core.c
where they have lived. We can also unexport blk_end_bidi_request() and
__blk_end_bidi_request(), which nobody uses.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 11:06:48 +02:00
Tejun Heo
9934c8c045 block: implement and enforce request peek/start/fetch
Till now block layer allowed two separate modes of request execution.
A request is always acquired from the request queue via
elv_next_request().  After that, drivers are free to either dequeue it
or process it without dequeueing.  Dequeue allows elv_next_request()
to return the next request so that multiple requests can be in flight.

Executing requests without dequeueing has its merits mostly in
allowing drivers for simpler devices which can't do sg to deal with
segments only without considering request boundary.  However, the
benefit this brings is dubious and declining while the cost of the API
ambiguity is increasing.  Segment based drivers are usually for very
old or limited devices and as converting to dequeueing model isn't
difficult, it doesn't justify the API overhead it puts on block layer
and its more modern users.

Previous patches converted all block low level drivers to dequeueing
model.  This patch completes the API transition by...

* renaming elv_next_request() to blk_peek_request()

* renaming blkdev_dequeue_request() to blk_start_request()

* adding blk_fetch_request() which is combination of peek and start

* disallowing completion of queued (not started) requests

* applying new API to all LLDs

Renamings are for consistency and to break out of tree code so that
it's apparent that out of tree drivers need updating.

[ Impact: block request issue API cleanup, no functional change ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: unsik Kim <donari75@gmail.com>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Laurent Vivier <Laurent@lvivier.info>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:52:18 +02:00
Tejun Heo
a2dec7b363 block: hide request sector and data_len
Block low level drivers for some reason have been pretty good at
abusing block layer API.  Especially struct request's fields tend to
get violated in all possible ways.  Make it clear that low level
drivers MUST NOT access or manipulate rq->sector and rq->data_len
directly by prefixing them with double underscores.

This change is also necessary to break build of out-of-tree codes
which assume the previous block API where internal fields can be
manipulated and rq->data_len carries residual count on completion.

[ Impact: hide internal fields, block API change ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:55 +02:00
Tejun Heo
2e46e8b27a block: drop request->hard_* and *nr_sectors
struct request has had a few different ways to represent some
properties of a request.  ->hard_* represent block layer's view of the
request progress (completion cursor) and the ones without the prefix
are supposed to represent the issue cursor and allowed to be updated
as necessary by the low level drivers.  The thing is that as block
layer supports partial completion, the two cursors really aren't
necessary and only cause confusion.  In addition, manual management of
request detail from low level drivers is cumbersome and error-prone at
the very least.

Another interesting duplicate fields are rq->[hard_]nr_sectors and
rq->{hard_cur|current}_nr_sectors against rq->data_len and
rq->bio->bi_size.  This is more convoluted than the hard_ case.

rq->[hard_]nr_sectors are initialized for requests with bio but
blk_rq_bytes() uses it only for !pc requests.  rq->data_len is
initialized for all request but blk_rq_bytes() uses it only for pc
requests.  This causes good amount of confusion throughout block layer
and its drivers and determining the request length has been a bit of
black magic which may or may not work depending on circumstances and
what the specific LLD is actually doing.

rq->{hard_cur|current}_nr_sectors represent the number of sectors in
the contiguous data area at the front.  This is mainly used by drivers
which transfers data by walking request segment-by-segment.  This
value always equals rq->bio->bi_size >> 9.  However, data length for
pc requests may not be multiple of 512 bytes and using this field
becomes a bit confusing.

In general, having multiple fields to represent the same property
leads only to confusion and subtle bugs.  With recent block low level
driver cleanups, no driver is accessing or manipulating these
duplicate fields directly.  Drop all the duplicates.  Now rq->sector
means the current sector, rq->data_len the current total length and
rq->bio->bi_size the current segment length.  Everything else is
defined in terms of these three and available only through accessors.

* blk_recalc_rq_sectors() is collapsed into blk_update_request() and
  now handles pc and fs requests equally other than rq->sector update.
  This means that now pc requests can use partial completion too (no
  in-kernel user yet tho).

* bio_cur_sectors() is replaced with bio_cur_bytes() as block layer
  now uses byte count as the primary data length.

* blk_rq_pos() is now guranteed to be always correct.  In-block users
  converted.

* blk_rq_bytes() is now guaranteed to be always valid as is
  blk_rq_sectors().  In-block users converted.

* blk_rq_sectors() is now guaranteed to equal blk_rq_bytes() >> 9.
  More convenient one is used.

* blk_rq_bytes() and blk_rq_cur_bytes() are now inlined and take const
  pointer to request.

[ Impact: API cleanup, single way to represent one property of a request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:54 +02:00
Tejun Heo
83096ebf12 block: convert to pos and nr_sectors accessors
With recent cleanups, there is no place where low level driver
directly manipulates request fields.  This means that the 'hard'
request fields always equal the !hard fields.  Convert all
rq->sectors, nr_sectors and current_nr_sectors references to
accessors.

While at it, drop superflous blk_rq_pos() < 0 test in swim.c.

[ Impact: use pos and nr_sectors accessors ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Mike Miller <mike.miller@hp.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: unsik Kim <donari75@gmail.com>
Cc: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:54 +02:00
Tejun Heo
5b93629b45 block: implement blk_rq_pos/[cur_]sectors() and convert obvious ones
Implement accessors - blk_rq_pos(), blk_rq_sectors() and
blk_rq_cur_sectors() which return rq->hard_sector, rq->hard_nr_sectors
and rq->hard_cur_sectors respectively and convert direct references of
the said fields to the accessors.

This is in preparation of request data length handling cleanup.

Geert	: suggested adding const to struct request * parameter to accessors
Sergei	: spotted error in patch description

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Ackec-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:53 +02:00
Tejun Heo
c3a4d78c58 block: add rq->resid_len
rq->data_len served two purposes - the length of data buffer on issue
and the residual count on completion.  This duality creates some
headaches.

First of all, block layer and low level drivers can't really determine
what rq->data_len contains while a request is executing.  It could be
the total request length or it coulde be anything else one of the
lower layers is using to keep track of residual count.  This
complicates things because blk_rq_bytes() and thus
[__]blk_end_request_all() relies on rq->data_len for PC commands.
Drivers which want to report residual count should first cache the
total request length, update rq->data_len and then complete the
request with the cached data length.

Secondly, it makes requests default to reporting full residual count,
ie. reporting that no data transfer occurred.  The residual count is
an exception not the norm; however, the driver should clear
rq->data_len to zero to signify the normal cases while leaving it
alone means no data transfer occurred at all.  This reverse default
behavior complicates code unnecessarily and renders block PC on some
drivers (ide-tape/floppy) unuseable.

This patch adds rq->resid_len which is used only for residual count.

While at it, remove now unnecessasry blk_rq_bytes() caching in
ide_pc_intr() as rq->data_len is not changed anymore.

Boaz	: spotted missing conversion in osd
Sergei	: spotted too early conversion to blk_rq_bytes() in ide-tape

[ Impact: cleanup residual count handling, report 0 resid by default ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:53 +02:00
Ingo Molnar
44347d947f Merge branch 'linus' into tracing/core
Merge reason: tracing/core was on a .30-rc1 base and was missing out on
              on a handful of tracing fixes present in .30-rc5-almost.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-07 11:17:34 +02:00
Alan D. Brunelle
22a7c31a96 blktrace: from-sector redundant in trace_block_remap
Remove redundant from-sector parameter: it's /always/ the bio's sector
passed in.

[ Impact: cleanup ]

Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49FF517C.7000503@hp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-06 14:13:01 +02:00
Tejun Heo
4c94dece1b block: don't init rq fields unnecessarily
blk_get_request() always returns properly zeroed requests.  Don't set
fields to zero/NULL unnecessarily.

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-28 08:14:50 +02:00
Nikanth Karthikesan
9eb55b030c block: catch trying to use more bits than request->cmd_flags has
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-28 07:37:37 +02:00
Jens Axboe
c69d48540c block: include discard requests in IO accounting
We currently don't do merging on discard requests, but we potentially
could. If we do, then we need to include discard requests in the IO
accounting, or merging would end up decrementing in_flight IO counters
for an IO which never incremented them.

So enable accounting for discard requests.

Problem found by Nikanth Karthikesan <knikanth@suse.de>

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-28 07:37:37 +02:00
Jens Axboe
c2553b5844 block: make blk_do_io_stat() do the full "is this rq accountable" checks
We currently check for file system requests outside of blk_do_io_stat(rq),
but we may as well just include it.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-28 07:37:37 +02:00
Tejun Heo
731ec497e5 block: kill rq->data
Now that all block request data transfer is done via bio, rq->data
isn't used.  Kill it.

While at it, make the roles of rq->special and buffer clear.

[ Impact: drop now unncessary field from struct request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Boaz Harrosh <bharrosh@panasas.com>
2009-04-28 07:37:36 +02:00
Tejun Heo
40cbbb781d block: implement and use [__]blk_end_request_all()
There are many [__]blk_end_request() call sites which call it with
full request length and expect full completion.  Many of them ensure
that the request actually completes by doing BUG_ON() the return
value, which is awkward and error-prone.

This patch adds [__]blk_end_request_all() which takes @rq and @error
and fully completes the request.  BUG_ON() is added to to ensure that
this actually happens.

Most conversions are simple but there are a few noteworthy ones.

* cdrom/viocd: viocd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/block/dasd: dasd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/char/tape_block: tapeblock_end_request() replaced with direct
  calls to blk_end_request_all().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-04-28 07:37:35 +02:00
Tejun Heo
b243ddcbe9 block: move rq->start_time initialization to blk_rq_init()
rq->start_time was initialized in init_request_from_bio() so special
requests didn't have start_time set.  This has been okay as start_time
has been used only for fs requests; however, there is no indication of
this actually is the case or not.  Set rq->start_time in blk_rq_init()
and guarantee that all initialized rq's have its start_time set.  This
improves consistency at virtually no cost and future changes will make
use of the timestamp for !bio requests.

[ Impact: rq->start_time is valid for all requests ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:35 +02:00
Tejun Heo
2e60e02297 block: clean up request completion API
Request completion has gone through several changes and became a bit
messy over the time.  Clean it up.

1. end_that_request_data() is a thin wrapper around
   end_that_request_data_first() which checks whether bio is NULL
   before doing anything and handles bidi completion.
   blk_update_request() is a thin wrapper around
   end_that_request_data() which clears nr_sectors on the last
   iteration but doesn't use the bidi completion.

   Clean it up by moving the initial bio NULL check and nr_sectors
   clearing on the last iteration into end_that_request_data() and
   renaming it to blk_update_request(), which makes blk_end_io() the
   only user of end_that_request_data().  Collapse
   end_that_request_data() into blk_end_io().

2. There are four visible completion variants - blk_end_request(),
   __blk_end_request(), blk_end_bidi_request() and end_request().
   blk_end_request() and blk_end_bidi_request() uses blk_end_request()
   as the backend but __blk_end_request() and end_request() use
   separate implementation in __blk_end_request() due to different
   locking rules.

   blk_end_bidi_request() is identical to blk_end_io().  Collapse
   blk_end_io() into blk_end_bidi_request(), separate out request
   update into internal helper blk_update_bidi_request() and add
   __blk_end_bidi_request().  Redefine [__]blk_end_request() as thin
   inline wrappers around [__]blk_end_bidi_request().

3. As the whole request issue/completion usages are about to be
   modified and audited, it's a good chance to convert completion
   functions return bool which better indicates the intended meaning
   of return values.

4. The function name end_that_request_last() is from the days when it
   was a public interface and slighly confusing.  Give it a proper
   internal name - blk_finish_request().

5. Add description explaning that blk_end_bidi_request() can be safely
   used for uni requests as suggested by Boaz Harrosh.

The only visible behavior change is from #1.  nr_sectors counts are
cleared after the final iteration no matter which function is used to
complete the request.  I couldn't find any place where the code
assumes those nr_sectors counters contain the values for the last
segment and this change is good as it makes the API much more
consistent as the end result is now same whether a request is
completed using [__]blk_end_request() alone or in combination with
blk_update_request().

API further cleaned up per Christoph's suggestion.

[ Impact: cleanup, rq->*nr_sectors always updated after req completion ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Christoph Hellwig <hch@infradead.org>
2009-04-28 07:37:35 +02:00
Tejun Heo
0b302d5aa7 block: kill blk_end_request_callback()
With recent IDE updates, blk_end_request_callback() doesn't have any
user now.  Kill it.

[ Impact: removal of unused convoluted interface ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
158dbda006 block: reorganize request fetching functions
Impact: code reorganization

elv_next_request() and elv_dequeue_request() are public block layer
interface than actual elevator implementation.  They mostly deal with
how requests interact with block layer and low level drivers at the
beginning of rqeuest processing whereas __elv_next_request() is the
actual eleveator request fetching interface.

Move the two functions to blk-core.c.  This prepares for further
interface cleanup.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
5efccd17ce block: reorder request completion functions
Reorder request completion functions such that

* All request completion functions are located together.

* Functions which are used by only one caller is put right above the
  caller.

* end_request() is put after other completion functions but before
  blk_update_request().

This change is for completion function cleanup which will follow.

[ Impact: cleanup, code reorganization ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
2eef33e439 block: clean up misc stuff after block layer timeout conversion
* In blk_rq_timed_out_timer(), else { if } to else if

* In blk_add_timer(), simplify if/else block

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
10732f5661 block: cleanup REQ_SOFTBARRIER usages
blk_insert_request() doesn't need to worry about REQ_SOFTBARRIER.
Don't set it.  Combined with recent ide updates, REQ_SOFTBARRIER is
now only used in elevator proper and for discard requests.

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
e4025f6c21 block: don't set REQ_NOMERGE unnecessarily
RQ_NOMERGE_FLAGS already clears defines which REQ flags aren't
mergeable.  There is no reason to specify it superflously.  It only
adds to confusion.  Don't set REQ_NOMERGE for barriers and requests
with specific queueing directive.  REQ_NOMERGE is now exclusively used
by the merging code.

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:33 +02:00
Tejun Heo
a7f5579234 block: kill blk_start_queueing()
blk_start_queueing() is identical to __blk_run_queue() except that it
doesn't check for recursion.  None of the current users depends on
blk_start_queueing() running request_fn directly.  Replace usages of
blk_start_queueing() with [__]blk_run_queue() and kill it.

[ Impact: removal of mostly duplicate interface function ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:33 +02:00
Tejun Heo
a538cd03be block: merge blk_invoke_request_fn() into __blk_run_queue()
__blk_run_queue wraps blk_invoke_request_fn() such that it
additionally removes plug and bails out early if the queue is empty.
Both extra operations have their own pending mechanisms and don't
cause any harm correctness-wise when they are done superflously.

The only user of blk_invoke_request_fn() being blk_start_queue(),
there isn't much reason to keep both functions around.  Merge
blk_invoke_request_fn() into __blk_run_queue() and make
blk_start_queue() use __blk_run_queue() instead.

[ Impact: merge two subtly different internal functions ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:33 +02:00
Bartlomiej Zolnierkiewicz
db29a6b496 block: enable by default support for large devices and files on 32-bit archs
Enable by default support for large devices and files (CONFIG_LBD):

- With 1TB disks being a commodity hardware it is quite easy to hit 2TB
  limitation while building RAIDs etc. and many distros have been using
  CONFIG_LBD=y by default already (at least Fedora 10 and openSUSE 11.1).

- This should also prevent a subtle ext4 filesystem compatibility issue:
  mke2fs.ext4 defaults to creating filesystems with huge_files feature
  enabled and such filesystems cannot be later mounted read-write on
  machines with CONFIG_LBD=n (it should be quite easy to hit this issue
  when trying to use filesystem created using distro kernel on system
  running the self-build kernel, think about USB disk enclosures & co.).

While at it:

- Clarify config option help text w.r.t. mounting ext4 filesystems
  (they can be mounted with CONFIG_LBD=n but in the read-only mode).

Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-28 07:37:33 +02:00
Tejun Heo
924cec7789 block: clear req->errors on bio completion only for fs requests
Impact: subtle behavior change

For fs requests, rq is only carrier of bios and rq error status as a
whole doesn't mean much.  This is the reason why rq->errors is being
cleared on each partial completion of a request as on each partial
completion the error status is transferred to the respective bios.

For pc requests, rq->errors is used to carry error status to the
issuer and thus __end_that_request_first() doesn't clear it on such
cases.

The condition was fine till now as only fs and pc requests have used
bio and thus the bio completion path.  However, future changes will
unify data accesses to bio and all non fs users care about rq error
status.  Clear rq->errors on bio completion only for fs requests.

In general, the implicit clearing is a bit too subtle especially as
the meaning of rq->errors is completely dependent on low level
drivers.  Unifying / cleaning up rq->errors usage and letting llds
manage it would be better.  TODO comment added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
2009-04-28 07:37:28 +02:00
Jens Axboe
f2d1f0ae78 cfq-iosched: cache prio_tree root in cfqq->p_root
Currently we look it up from ->ioprio, but ->ioprio can change if
either the process gets its IO priority changed explicitly, or if
cfq decides to temporarily boost it. So if we are unlucky, we can
end up attempting to remove a node from a different rbtree root than
where it was added.

Fix this by using ->org_ioprio as the prio_tree index, since that
will only change for explicit IO priority settings (not for a boost).
Additionally cache the rbtree root inside the cfqq, then we don't have
to add code to reinsert the cfqq in the prio_tree if IO priority changes.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-24 08:54:22 +02:00
Jens Axboe
3ac6c9f8a6 cfq-iosched: fix bug with aliased request and cooperation detection
cfq_prio_tree_lookup() should return the direct match, yet it always
returns zero. Fix that.

cfq_prio_tree_add() assumes that we don't get a direct match, while
it is very possible that we do. Using O_DIRECT, you can have different
cfqq with matching requests, since you don't have the page cache
to serialize things for you. Fix this bug by only adding the cfqq if
there isn't an existing match.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-24 08:54:22 +02:00
Jens Axboe
26a2ac009c cfq-iosched: clear ->prio_trees[] on cfqd alloc
Not strictly needed, but we should make it clear that we init the
rbtree roots here.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-24 08:54:22 +02:00
Hannes Reinecke
17d5c8ca75 block: fix intermittent dm timeout based oops
Very rarely under stress testing of dm, oopses are occuring as
something tampers with an old stack frame.  This has been traced back
to blk_abort_queue() leaving a timeout_list pointing to the stack.
The reason is that sometimes blk_abort_request() won't delete the
timer (if the request is marked as complete but before the timer has
been removed, a small race window).  Fix this by splicing back from
the ususally empty list to the q->timeout_list.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-24 08:54:21 +02:00
Jerome Marchand
42dad7647a block: simplify I/O stat accounting
This simplifies I/O stat accounting switching code and separates it
completely from I/O scheduler switch code.

Requests are accounted according to the state of their request queue
at the time of the request allocation. There is no need anymore to
flush the request queue when switching I/O accounting state.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-24 08:54:21 +02:00
Jeff Moyer
04dc6e71a2 cfq-iosched: use the default seek distance when there aren't enough seek samples
If the cfq io context doesn't have enough samples yet to provide a mean
seek distance, then use the default threshold we have for seeky IO instead
of defaulting to 0.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-22 08:35:11 +02:00
Jeff Moyer
4d00aa47e2 cfq-iosched: make seek_mean converge more quickly
Right now, depending on the first sector to which a process issues I/O,
the seek time may start out way out of whack. So make sure we start
with 0 sectors in seek, instead of the offset of the first request
issued.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-22 08:35:11 +02:00
Jens Axboe
b759113499 block: make blk_abort_queue() ignore non-request based devices
There's nothing to do for those devices, since the timeout handling is
based on requests.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-22 08:35:10 +02:00
Tejun Heo
71982a409f block: include empty disks in /proc/diskstats
/proc/diskstats used to show stats for all disks whether they're
zero-sized or not and their non-zero partitions.  Commit
074a7aca7a accidentally changed the
behavior such that it doesn't print out zero sized disks.  This patch
implements DISK_PITER_INCL_EMPTY_PART0 flag to partition iterator and
uses it in diskstats_show() such that empty part0 is shown in
/proc/diskstats.

Reported and bisectd by Dianel Collins.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Daniel Collins <solemnwarning@solemnwarning.no-ip.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-22 08:35:10 +02:00
Tejun Heo
cd0aca2d55 block: fix queue bounce limit setting
Impact: don't set GFP_DMA in q->bounce_gfp unnecessarily

All DMA address limits are expressed in terms of the last addressable
unit (byte or page) instead of one plus that.  However, when
determining bounce_gfp for 64bit machines in blk_queue_bounce_limit(),
it compares the specified limit against 0x100000000UL to determine
whether it's below 4G ending up falsely setting GFP_DMA in
q->bounce_gfp.

As DMA zone is very small on x86_64, this makes larger SG_IO transfers
very eager to trigger OOM killer.  Fix it.  While at it, rename the
parameter to @dma_mask for clarity and convert comment to proper
winged style.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-22 08:35:09 +02:00
Tejun Heo
25636e282f block: fix SG_IO vector request data length handling
Impact: fix SG_IO behavior such that it matches the documentation

SG_IO howto says that if ->dxfer_len and sum of iovec disagress, the
shorter one wins.  However, the current implementation returns -EINVAL
for such cases.  Trim iovc if it's longer than ->dxfer_len.

This patch uses iov_*() helpers which take struct iovec * by casting
struct sg_iovec * to it.  sg_iovec is always identical to iovec and
this will be further cleaned up with later patches.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-22 08:35:09 +02:00
Tejun Heo
6f41469c62 block: clear req->errors on bio completion only for fs requests
Impact: subtle behavior change

For fs requests, rq is only carrier of bios and rq error status as a
whole doesn't mean much.  This is the reason why rq->errors is being
cleared on each partial completion of a request as on each partial
completion the error status is transferred to the respective bios.

For pc requests, rq->errors is used to carry error status to the
issuer and thus __end_that_request_first() doesn't clear it on such
cases.

The condition was fine till now as only fs and pc requests have used
bio and thus the bio completion path.  However, future changes will
unify data accesses to bio and all non fs users care about rq error
status.  Clear rq->errors on bio completion only for fs requests.

In general, the implicit clearing is a bit too subtle especially as
the meaning of rq->errors is completely dependent on low level
drivers.  Unifying / cleaning up rq->errors usage and letting llds
manage it would be better.  TODO comment added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
2009-04-19 07:00:41 +09:00
Li Zefan
1d54ad6da9 blktrace: add trace/ to /sys/block/sda
Impact: allow ftrace-plugin blktrace to trace device-mapper devices

To trace a single partition:
  # echo 1 > /sys/block/sda/sda1/enable

To trace the whole sda instead:
  # echo 1 > /sys/block/sda/enable

Thus we also fix an issue reported by Ted, that ftrace-plugin blktrace
can't be used to trace device-mapper devices.

Now:

  # echo 1 > /sys/block/dm-0/trace/enable
  echo: write error: No such device or address
  # mount -t ext4 /dev/dm-0 /mnt
  # echo 1 > /sys/block/dm-0/trace/enable
  # echo blk > /debug/tracing/current_tracer

Reported-by: Theodore Tso <tytso@mit.edu>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Shawn Du <duyuyang@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42665.6020506@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-16 10:10:59 +02:00
Shawn Du
d0deef5b14 blktrace: support per-partition tracing
Though one can specify '-d /dev/sda1' when using blktrace, it still
traces the whole sda.

To support per-partition tracing, when we start tracing, we initialize
bt->start_lba and bt->end_lba to the start and end sector of that
partition.

Note some actions are per device, thus we don't filter 0-sector events.

The original patch and discussion can be found here:
	http://marc.info/?l=linux-btrace&m=122949374214540&w=2

Signed-off-by: Shawn Du <duyuyang@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42620.4050701@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-16 10:10:57 +02:00
Jens Axboe
a36e71f996 cfq-iosched: add close cooperator code
If we have processes that are working in close proximity to each
other on disk, we don't want to idle wait. Instead allow the close
process to issue a request, getting better aggregate bandwidth.
The anticipatory scheduler has similar checks, noop and deadline do
not need it since they don't care about process <-> io mappings.

The code for CFQ is a little more involved though, since we split
request queues into per-process contexts.

This fixes a performance problem with eg dump(8), since it uses
several processes in some silly attempt to speed IO up. Even if
dump(8) isn't really a valid case (it should be fixed by using
CLONE_IO), there are other cases where we see close processes
and where idling ends up hurting performance.

Credit goes to Jeff Moyer <jmoyer@redhat.com> for writing the
initial implementation.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 12:15:11 +02:00
Jens Axboe
9481ffdc61 cfq-iosched: log responsible 'cfqq' in idle timer arm
Makes it easier to read the traces.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 12:14:13 +02:00
Jens Axboe
2d87072296 cfq-iosched: tweak kick logic a bit more
We only kick the dispatch for an idling queue, if we think it's a
(somewhat) fully merged request. Also allow a kick if we have other
busy queues in the system, since we don't want to risk waiting for
a potential merge in that case. It's better to get some work done and
proceed.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 12:12:46 +02:00
Jens Axboe
40bb54d197 cfq-iosched: no need to save interrupts in cfq_kick_queue()
It's called from the workqueue handlers from process context, so
we always have irqs enabled when entered.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 12:11:10 +02:00
Nikanth Karthikesan
15afd1cc7b block: Remove code handling bio_alloc failure with __GFP_WAIT
Remove code handling bio_alloc failure with __GFP_WAIT.
GFP_KERNEL implies __GFP_WAIT.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 12:10:12 +02:00
FUJITA Tomonori
91e463c8f5 block: fix SG_IO to return a proper error value
blk_rq_unmap_user() returns -EFAULT if a program passes an invalid
address to kernel. SG_IO path needs to pass the returned value to user
space instead of ignoring it.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 12:10:11 +02:00
Jens Axboe
d6ceb25e8d cfq-iosched: don't delay queue kick for a merged request
"Zhang, Yanmin" <yanmin_zhang@linux.intel.com> reports that commit
b029195dda introduced a regression
of about 50% with sequential threaded read workloads. The test
case is:

tiotest -k0 -k1 -k3 -f 80 -t 32

which starts 32 threads each reading a 80MB file. Twiddle the kick
queue logic so that we do start IO immediately, if it appears to be
a fully merged request. We can't really detect that, so just check
if the request is bigger than a page or not. The assumption is that
since single bio issues will first queue a single request with just
one page attached and then later do merges on that, if we already
have more than a page worth of data in the request, then the request
is most likely good to go.

Verified that this doesn't cause a regression with the test case that
commit b029195dda was fixing. It does not,
we still see maximum sized requests for the queue-then-merge cases.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 08:28:12 +02:00
Jens Axboe
1d6bfbdf38 as-iosched: get rid of private REQ_SYNC/REQ_ASYNC defines
We can just use the block layer BLK_RW_SYNC/ASYNC defines now.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 08:28:10 +02:00
Jens Axboe
ff6657c6c8 cfq-iosched: get rid of private SYNC/ASYNC defines
We can just use the block layer BLK_RW_SYNC/ASYNC defines now.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 08:28:10 +02:00
Jens Axboe
b0b78f81a5 cfq-iosched: use rw_is_sync() to see if rw flags are sync or not
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 08:28:10 +02:00
Jens Axboe
f600abe2de block: fix bad spelling of quiesce
Credit goes to Andrew Morton for spotting this one.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-15 08:28:09 +02:00
Linus Torvalds
c93f216b5b Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y
  branch tracer: Fix for enabling branch profiling makes sparse unusable
  ftrace: Correct a text align for event format output
  Update /debug/tracing/README
  tracing/ftrace: alloc the started cpumask for the trace file
  tracing, x86: remove duplicated #include
  ftrace: Add check of sched_stopped for probe_sched_wakeup
  function-graph: add proper initialization for init task
  tracing/ftrace: fix missing include string.h
  tracing: fix incorrect return type of ns2usecs()
  tracing: remove CALLER_ADDR2 from wakeup tracer
  blktrace: fix pdu_len when tracing packet command requests
  blktrace: small cleanup in blk_msg_write()
  blktrace: NUL-terminate user space messages
  tracing: move scripts/trace/power.pl to scripts/tracing/power.pl
2009-04-07 14:10:10 -07:00
Linus Torvalds
6a5d263866 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  loop: mutex already unlocked in loop_clr_fd()
  cfq-iosched: don't let idling interfere with plugging
  block: remove unused REQ_UNPLUG
  cfq-iosched: kill two unused cfqq flags
  cfq-iosched: change dispatch logic to deal with single requests at the time
  mflash: initial support
  cciss: change to discover first memory BAR
  cciss: kernel scan thread for MSA2012
  cciss: fix residual count for block pc requests
  block: fix inconsistency in I/O stat accounting code
  block: elevator quiescing helpers
2009-04-07 11:06:41 -07:00
Linus Torvalds
132ea5e9aa Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  sata_mv: shorten register names
  sata_mv: workaround errata SATA#13
  sata_mv: cosmetic renames
  sata_mv: workaround errata SATA#26
  sata_mv: workaround errata PCI#7
  sata_mv: replace 0x1f with ATA_PIO4 (v2)
  sata_mv: fix irq mask races
  sata_mv: revert SoC irq breakage
  libata: ahci enclosure management bios workaround
  ata: Add TRIM infrastructure
  ata_piix: VGN-BX297XP wants the controller power up on suspend
  libata: Remove some redundant casts from pata_octeon_cf.c
  pata_artop: typo
2009-04-07 08:53:02 -07:00
Jens Axboe
b029195dda cfq-iosched: don't let idling interfere with plugging
When CFQ is waiting for a new request from a process, currently it'll
immediately restart queuing when it sees such a request. This doesn't
work very well with streamed IO, since we then end up splitting IO
that would otherwise have been merged nicely. For a simple dd test,
this causes 10x as many requests to be issued as we should have.
Normally this goes unnoticed due to the low overhead of requests
at the device side, but some hardware is very sensitive to request
sizes and there it can cause big slow downs.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 11:38:31 +02:00
Jens Axboe
2385327725 block: remove unused REQ_UNPLUG
The request inherits the unplug flag from the bio, but it isn't actually
used. The bio flag stops at __make_request(), which tells it to unplug
after submission. Passing it on to the request doesn't make any sense.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 08:59:11 +02:00
Jens Axboe
75e50984f0 cfq-iosched: kill two unused cfqq flags
We only manipulate the must_dispatch and queue_new flags, they are not
tested anymore. So get rid of them.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 08:56:14 +02:00
Jens Axboe
2f5cb7381b cfq-iosched: change dispatch logic to deal with single requests at the time
The IO scheduler core calls into the IO scheduler dispatch_request hook
to move requests from the IO scheduler and into the driver dispatch
list. It only does so when the dispatch list is empty. CFQ moves several
requests to the dispatch list, which can cause higher latencies if we
suddenly have to switch to some important sync IO. Change the logic to
move one request at the time instead.

This should almost be functionally equivalent to what we did before,
except that we now honor 'quantum' as the maximum queue depth at the
device side from any single cfqq. If there's just a single active
cfqq, we allow up to 4 times the normal quantum.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 08:51:19 +02:00
Jerome Marchand
26308eab69 block: fix inconsistency in I/O stat accounting code
This forces in_flight to be zero when turning off or on the I/O stat
accounting and stops updating I/O stats in attempt_merge() when
accounting is turned off.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 08:12:38 +02:00
Jens Axboe
6c7e8cee6a block: elevator quiescing helpers
Simple helper functions to quiesce the request queue. These are
currently only used for switching IO schedulers on-the-fly, but
we can use them to properly switch IO accounting on and off as well.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 08:12:37 +02:00
Alan Cox
8feb4d20b4 pata_artop: typo
Fix a typo (this was in the original patch but was not merged when the code
fixes were for some reason)

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-04-06 20:00:29 -04:00
Jens Axboe
aeb6fafb8f block: Add flag for telling the IO schedulers NOT to anticipate more IO
By default, CFQ will anticipate more IO from a given io context if the
previously completed IO was sync. This used to be fine, since the only
sync IO was reads and O_DIRECT writes. But with more "normal" sync writes
being used now, we don't want to anticipate for those.

Add a bio/request flag that informs the IO scheduler that this is a sync
request that we should not idle for. Introduce WRITE_ODIRECT specifically
for O_DIRECT writes, and make sure that the other sync writes set this
flag.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-06 08:04:54 -07:00
Jens Axboe
644b2d99b7 block: enabling plugging on SSD devices that don't do queuing
For the older SSD devices that don't do command queuing, we do want to
enable plugging to get better merging.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-06 08:04:54 -07:00
Jens Axboe
1faa16d228 block: change the request allocation/congestion logic to be sync/async based
This makes sure that we never wait on async IO for sync requests, instead
of doing the split on writes vs reads.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-06 08:04:53 -07:00
Linus Torvalds
714f83d5d9 Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits)
  tracing, net: fix net tree and tracing tree merge interaction
  tracing, powerpc: fix powerpc tree and tracing tree interaction
  ring-buffer: do not remove reader page from list on ring buffer free
  function-graph: allow unregistering twice
  trace: make argument 'mem' of trace_seq_putmem() const
  tracing: add missing 'extern' keywords to trace_output.h
  tracing: provide trace_seq_reserve()
  blktrace: print out BLK_TN_MESSAGE properly
  blktrace: extract duplidate code
  blktrace: fix memory leak when freeing struct blk_io_trace
  blktrace: fix blk_probes_ref chaos
  blktrace: make classic output more classic
  blktrace: fix off-by-one bug
  blktrace: fix the original blktrace
  blktrace: fix a race when creating blk_tree_root in debugfs
  blktrace: fix timestamp in binary output
  tracing, Text Edit Lock: cleanup
  tracing: filter fix for TRACE_EVENT_FORMAT events
  ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
  x86: kretprobe-booster interrupt emulation code fix
  ...

Fix up trivial conflicts in
 arch/parisc/include/asm/ftrace.h
 include/linux/memory.h
 kernel/extable.c
 kernel/module.c
2009-04-05 11:04:19 -07:00
Linus Torvalds
90975ef712 Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask: (36 commits)
  cpumask: remove cpumask allocation from idle_balance, fix
  numa, cpumask: move numa_node_id default implementation to topology.h, fix
  cpumask: remove cpumask allocation from idle_balance
  x86: cpumask: x86 mmio-mod.c use cpumask_var_t for downed_cpus
  x86: cpumask: update 32-bit APM not to mug current->cpus_allowed
  x86: microcode: cleanup
  x86: cpumask: use work_on_cpu in arch/x86/kernel/microcode_core.c
  cpumask: fix CONFIG_CPUMASK_OFFSTACK=y cpu hotunplug crash
  numa, cpumask: move numa_node_id default implementation to topology.h
  cpumask: convert node_to_cpumask_map[] to cpumask_var_t
  cpumask: remove x86 cpumask_t uses.
  cpumask: use cpumask_var_t in uv_flush_tlb_others.
  cpumask: remove cpumask_t assignment from vector_allocation_domain()
  cpumask: make Xen use the new operators.
  cpumask: clean up summit's send_IPI functions
  cpumask: use new cpumask functions throughout x86
  x86: unify cpu_callin_mask/cpu_callout_mask/cpu_initialized_mask/cpu_sibling_setup_mask
  cpumask: convert struct cpuinfo_x86's llc_shared_map to cpumask_var_t
  cpumask: convert node_to_cpumask_map[] to cpumask_var_t
  x86: unify 32 and 64-bit node_to_cpumask_map
  ...
2009-04-05 10:33:07 -07:00
Linus Torvalds
b1dbb67911 Merge branch 'ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  s390: remove arch specific smp_send_stop()
  panic: clean up kernel/panic.c
  panic, smp: provide smp_send_stop() wrapper on UP too
  panic: decrease oops_in_progress only after having done the panic
  generic-ipi: eliminate WARN_ON()s during oops/panic
  generic-ipi: cleanups
  generic-ipi: remove CSD_FLAG_WAIT
  generic-ipi: remove kmalloc()
  generic IPI: simplify barriers and locking
2009-04-03 17:33:30 -07:00
Li Zefan
e2494e1b42 blktrace: fix pdu_len when tracing packet command requests
Impact: output all of packet commands - not just the first 4 / 8 bytes

Since commit d7e3c3249e ("block: add
large command support"), struct request->cmd has been changed from
unsinged char cmd[BLK_MAX_CDB] to unsigned char *cmd.

v1 -> v2: by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

- make sure rq->cmd_len is always intialized, and then we can use
  rq->cmd_len instead of BLK_MAX_CDB.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49D4507E.2060602@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-03 15:29:26 +02:00
Ingo Molnar
8302294f43 Merge branch 'tracing/core-v2' into tracing-for-linus
Conflicts:
	include/linux/slub_def.h
	lib/Kconfig.debug
	mm/slob.c
	mm/slub.c
2009-04-02 00:49:02 +02:00
Ingo Molnar
65fb0d23fc Merge branch 'linus' into cpumask-for-linus
Conflicts:
	arch/x86/kernel/cpu/common.c
2009-03-30 23:53:32 +02:00
Linus Torvalds
7c730ccdc1 Merge branch 'percpu-cpumask-x86-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'percpu-cpumask-x86-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (682 commits)
  percpu: fix spurious alignment WARN in legacy SMP percpu allocator
  percpu: generalize embedding first chunk setup helper
  percpu: more flexibility for @dyn_size of pcpu_setup_first_chunk()
  percpu: make x86 addr <-> pcpu ptr conversion macros generic
  linker script: define __per_cpu_load on all SMP capable archs
  x86: UV: remove uv_flush_tlb_others() WARN_ON
  percpu: finer grained locking to break deadlock and allow atomic free
  percpu: move fully free chunk reclamation into a work
  percpu: move chunk area map extension out of area allocation
  percpu: replace pcpu_realloc() with pcpu_mem_alloc() and pcpu_mem_free()
  x86, percpu: setup reserved percpu area for x86_64
  percpu, module: implement reserved allocation and use it for module percpu variables
  percpu: add an indirection ptr for chunk page map access
  x86: make embedding percpu allocator return excessive free space
  percpu: use negative for auto for pcpu_setup_first_chunk() arguments
  percpu: improve first chunk initial area map handling
  percpu: cosmetic renames in pcpu_setup_first_chunk()
  percpu: clean up percpu constants
  x86: un-__init fill_pud/pmd/pte
  x86: remove vestigial fix_ioremap prototypes
  ...

Manually merge conflicts in arch/ia64/kernel/irq_ia64.c
2009-03-28 13:48:38 -07:00
Linus Torvalds
d54b3538b0 Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (119 commits)
  [SCSI] scsi_dh_rdac: Retry for NOT_READY check condition
  [SCSI] mpt2sas: make global symbols unique
  [SCSI] sd: Make revalidate less chatty
  [SCSI] sd: Try READ CAPACITY 16 first for SBC-2 devices
  [SCSI] sd: Refactor sd_read_capacity()
  [SCSI] mpt2sas v00.100.11.15
  [SCSI] mpt2sas: add MPT2SAS_MINOR(221) to miscdevice.h
  [SCSI] ch: Add scsi type modalias
  [SCSI] 3w-9xxx: add power management support
  [SCSI] bsg: add linux/types.h include to bsg.h
  [SCSI] cxgb3i: fix function descriptions
  [SCSI] libiscsi: fix possbile null ptr session command cleanup
  [SCSI] iscsi class: remove host no argument from session creation callout
  [SCSI] libiscsi: pass session failure a session struct
  [SCSI] iscsi lib: remove qdepth param from iscsi host allocation
  [SCSI] iscsi lib: have lib create work queue for transmitting IO
  [SCSI] iscsi class: fix lock dep warning on logout
  [SCSI] libiscsi: don't cap queue depth in iscsi modules
  [SCSI] iscsi_tcp: replace scsi_debug/tcp_debug logging with iscsi conn logging
  [SCSI] libiscsi_tcp: replace tcp_debug/scsi_debug logging with session/conn logging
  ...
2009-03-28 13:30:43 -07:00
Ingo Molnar
6e15cf0486 Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2
Conflicts:
	arch/parisc/kernel/irq.c
	arch/x86/include/asm/fixmap_64.h
	arch/x86/include/asm/setup.h
	kernel/irq/handle.c

Semantic merge:
        arch/x86/include/asm/fixmap.h

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-27 17:28:43 +01:00
Boaz Harrosh
e7cbbf1bf1 bsg: Remove bogus check against request_queue->max_sectors
bsg submits REQ_TYPE_BLOCK_PC so the right check is max_hw_sectors.
But I've removed this check because right after, bsg proceeds with
calling blk_rq_map_user() which does all the right checks.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-26 11:01:25 +01:00
Boaz Harrosh
1cd96c242a block: WARN in __blk_put_request() for potential bio leak
Put a WARN_ON in __blk_put_request if it is about to
leak bio(s). This is a serious bug that can happen in error
handling code paths.

For this to work I have fixed a couple of places in block/ where
request->bio != NULL ownership was not honored. And a small cleanup
at sg_io() while at it.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-26 11:01:23 +01:00
Boaz Harrosh
05378940ca bsg: add support for tail queuing
Currently inherited from sg.c bsg will submit asynchronous request
 at the head-of-the-queue, (using "at_head" set in the call to
 blk_execute_rq_nowait()). This is bad in situation where the queues
 are full, requests will execute out of order, and can cause
 starvation of the first submitted requests.

The sg_io_v4->flags member is used and a bit is allocated to denote the
Q_AT_TAIL. Zero is to queue at_head as before, to be compatible with old
code at the write/read path. SG_IO code path behavior was changed so to
be the same as write/read behavior. SG_IO was very rarely used and breaking
compatibility with it is OK at this stage.

sg_io_hdr at sg.h also has a flags member and uses 3 bits from the first
nibble and one bit from the last nibble. Even though none of these bits
are supported by bsg, The second nibble is allocated for use by bsg. Just
in case.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
CC: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 12:35:17 +01:00
Jens Axboe
50e1749310 block: get rid of unused blkdev_free_rq() define
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 12:35:16 +01:00
Jens Axboe
f3b144aa7f block: remove various blk_queue_*() setting functions in blk_init_queue_node()
It calls blk_queue_make_request(), which sets the identical set of limits.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 12:35:16 +01:00
Ingo Molnar
cd80a8142e Merge branch 'x86/core' into core/ipi 2009-03-13 11:05:58 +01:00
Rusty Russell
c69fc56de1 cpumask: use topology_core_cpumask/topology_thread_cpumask instead of cpu_core_map/cpu_sibling_map
Impact: cleanup

This is presumably what those definitions are for, and while all archs
define cpu_core_map/cpu_sibling map, that's changing (eg. x86 wants to
change it to a pointer).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-03-13 14:49:46 +10:30
Ingo Molnar
25d500067d Merge branch 'linus' into core/ipi 2009-03-13 02:14:25 +01:00
James Bottomley
f290f1970f [SCSI] Make scsi.h independent of the rest of the scsi includes
This allows it to compile and be used on the ps3 platform that wants
to use the #define values in scsi.h without actually having
CONFIG_SCSI set.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-03-12 12:58:13 -05:00
Ingo Molnar
12e87e36e0 Merge branches 'tracing/doc', 'tracing/ftrace', 'tracing/printk' and 'linus' into tracing/core 2009-03-10 09:56:25 +01:00
Ingo Molnar
467c88fee5 Merge branches 'x86/apic', 'x86/asm', 'x86/fixmap', 'x86/memtest', 'x86/mm', 'x86/urgent', 'linus' and 'core/percpu' into x86/core 2009-03-10 09:26:38 +01:00
Jens Axboe
59247eaea5 block: fix missing bio back/front segment size setting in blk_recount_segments()
Commit 1e42807918 introduced a bug where we
don't get front/back segment sizes in the bio in blk_recount_segments().
Fix this by tracking the back bio as well as the front bio in
__blk_recalc_rq_segments(), this also cleans up the interface by getting
rid of the segment size pointer passing.

Tested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-06 08:55:24 +01:00
Ingo Molnar
91d75e209b Merge branch 'x86/core' into core/percpu 2009-03-04 02:29:19 +01:00
Ingo Molnar
f701d35407 Merge branches 'tracing/ftrace' and 'linus' into tracing/core 2009-02-27 09:04:43 +01:00
Jens Axboe
1e42807918 block: reduce stack footprint of blk_recount_segments()
blk_recalc_rq_segments() requires a request structure passed in, which
we don't have from blk_recount_segments(). So the latter allocates one on
the stack, using > 400 bytes of stack for that. This can cause us to spill
over one page of stack from ext4 at least:

 0)     4560     400   blk_recount_segments+0x43/0x62
 1)     4160      32   bio_phys_segments+0x1c/0x24
 2)     4128      32   blk_rq_bio_prep+0x2a/0xf9
 3)     4096      32   init_request_from_bio+0xf9/0xfe
 4)     4064     112   __make_request+0x33c/0x3f6
 5)     3952     144   generic_make_request+0x2d1/0x321
 6)     3808      64   submit_bio+0xb9/0xc3
 7)     3744      48   submit_bh+0xea/0x10e
 8)     3696     368   ext4_mb_init_cache+0x257/0xa6a [ext4]
 9)     3328     288   ext4_mb_regular_allocator+0x421/0xcd9 [ext4]
10)     3040     160   ext4_mb_new_blocks+0x211/0x4b4 [ext4]
11)     2880     336   ext4_ext_get_blocks+0xb61/0xd45 [ext4]
12)     2544      96   ext4_get_blocks_wrap+0xf2/0x200 [ext4]
13)     2448      80   ext4_da_get_block_write+0x6e/0x16b [ext4]
14)     2368     352   mpage_da_map_blocks+0x7e/0x4b3 [ext4]
15)     2016     352   ext4_da_writepages+0x2ce/0x43c [ext4]
16)     1664      32   do_writepages+0x2d/0x3c
17)     1632     144   __writeback_single_inode+0x162/0x2cd
18)     1488      96   generic_sync_sb_inodes+0x1e3/0x32b
19)     1392      16   sync_sb_inodes+0xe/0x10
20)     1376      48   writeback_inodes+0x69/0xb3
21)     1328     208   balance_dirty_pages_ratelimited_nr+0x187/0x2f9
22)     1120     224   generic_file_buffered_write+0x1d4/0x2c4
23)      896     176   __generic_file_aio_write_nolock+0x35f/0x393
24)      720      80   generic_file_aio_write+0x6c/0xc8
25)      640      80   ext4_file_write+0xa9/0x137 [ext4]
26)      560     320   do_sync_write+0xf0/0x137
27)      240      48   vfs_write+0xb3/0x13c
28)      192      64   sys_write+0x4c/0x74
29)      128     128   system_call_fastpath+0x16/0x1b

Split the segment counting out into a __blk_recalc_rq_segments() helper
to avoid allocating an onstack request just for checking the physical
segment count.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-26 10:45:48 +01:00
Márton Németh
9e8c0bccdc block: add documentation for register_blkdev()
Add documentation for register_blkdev() function and for the parameters.

Signed-off-by: Márton Németh <nm127@freemail.hu>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-26 10:45:48 +01:00
Peter Zijlstra
6e2756376c generic-ipi: remove CSD_FLAG_WAIT
Oleg noticed that we don't strictly need CSD_FLAG_WAIT, rework
the code so that we can use CSD_FLAG_LOCK for both purposes.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25 14:13:44 +01:00
Ingo Molnar
0edcf8d692 Merge branch 'tj-percpu' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu
Conflicts:
	arch/x86/include/asm/pgtable.h
2009-02-24 21:52:45 +01:00
Rusty Russell
313e458f81 alloc_percpu: add align argument to __alloc_percpu.
This prepares for a real __alloc_percpu, by adding an alignment argument.
Only one place uses __alloc_percpu directly, and that's for a string.

tj: af_inet also uses __alloc_percpu(), update it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
2009-02-20 16:29:08 +09:00
Ingo Molnar
72c26c9a26 Merge branch 'linus' into tracing/blktrace
Conflicts:
	block/blktrace.c

Semantic merge:
	kernel/trace/blktrace.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-19 09:00:35 +01:00
Hannes Reinecke
be987fdb55 block: fix deadlock in blk_abort_queue() for drivers that readd to timeout list
blk_abort_queue() iterates the timeout list and aborts each request on the
list, but if the driver error handling readds a request to the timeout list
during this processing, we could be looping forever. Fix this by splicing
current entries to a local list and run over that list instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-18 10:34:16 +01:00
Neil Brown
41b8c853a4 block: fix booting from partitioned md array
Hi Tejun,

 it looks like your commit:

   block: don't depend on consecutive minor space
   f331c0296f

 broke a particular case for booting from partitioned md/raid devices.
 That is the second time this has been broken recently.  The previous
 time was fixed by

   block: do_mounts - accept root=<non-existant partition>
   30f2f0eb4b

 Because the data isn't available when an md device is first created
 (we add disks and set it up after creation), the initial partition
 scan finds nothing.  It is not until the device is opened that
 another partition scan happens and finds something.

 So at the point where the kernel parameter "root=/dev/md_d0p1" is
 being parsed, md_d0 exists, but md_d0p1 does not.
 However if we let blk_lookup_devt return the correct device number
 even though the device doesn't exist, then the attempt to mount it
 will successfully find the partition.

 I have tried in the past to find a way to get the partition table to
 be read as soon as the array is assembled but that proved impossible
 (at the time).  I don't remember the details, and could possibly
 revisit it.  However it would be really nice if blk_lookup_devt
 could be adjusted to again accept non existant partitions.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-18 10:33:59 +01:00
Jens Axboe
93dbb39350 block: fix bad definition of BIO_RW_SYNC
We can't OR shift values, so get rid of BIO_RW_SYNC and use BIO_RW_SYNCIO
and BIO_RW_UNPLUG explicitly. This brings back the behaviour from before
213d9417fe.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-18 10:32:00 +01:00
Boaz Harrosh
c1c201200a bsg: Fix sense buffer bug in SG_IO
When submitting requests via SG_IO, which does a sync io, a
bsg_command is not allocated. So an in-Kernel sense_buffer was not
set. However when calling blk_execute_rq() with no sense buffer
one is provided from the stack. Now bsg at blk_complete_sgv4_hdr_rq()
would check if rq->sense_len and a sense was requested by sg_io_v4
the rq->sense was copy_user() back, but by now it is already mangled
stack memory.

I have fixed that by forcing a sense_buffer when calling bsg_map_hdr().
The bsg_command->sense is provided in the write/read path like before,
and on-the-stack buffer is provided when doing SG_IO.

I have also fixed a dprintk message to print rq->errors in hex because
of the scsi bit-field use of this member. For other block devices it
does not matter anyway.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-18 10:32:00 +01:00
Frederic Weisbecker
2db270a80b tracing/blktrace: move the tracing file to kernel/trace
Impact: cleanup

Move blktrace.c to kernel/trace, also move its config entry.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 10:51:02 +01:00
Arnaldo Carvalho de Melo
b6f11df26f trace: Call tracing_reset_online_cpus before tracer->init()
Impact: cleanup

To make it easy for ftrace plugin writers, as this was open coded in
the existing plugins

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:41 +01:00
Arnaldo Carvalho de Melo
51a763dd84 tracing: Introduce trace_buffer_{lock_reserve,unlock_commit}
Impact: new API

These new functions do what previously was being open coded, reducing
the number of details ftrace plugin writers have to worry about.

It also standardizes the handling of stacktrace, userstacktrace and
other trace options we may introduce in the future.

With this patch, for instance, the blk tracer (and some others already
in the tree) can use the "userstacktrace" /d/tracing/trace_options
facility.

$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
  trace_vprintk              |   -5
  trace_graph_return         |  -22
  trace_graph_entry          |  -26
  trace_function             |  -45
  __ftrace_trace_stack       |  -27
  ftrace_trace_userstack     |  -29
  tracing_sched_switch_trace |  -66
  tracing_stop               |   +1
  trace_seq_to_user          |   -1
  ftrace_trace_special       |  -63
  ftrace_special             |   +1
  tracing_sched_wakeup_trace |  -70
  tracing_reset_online_cpus  |   -1
 13 functions changed, 2 bytes added, 355 bytes removed, diff: -353

linux-2.6-tip/block/blktrace.c:
  __blk_add_trace |  -58
 1 function changed, 58 bytes removed, diff: -58

linux-2.6-tip/kernel/trace/trace.c:
  trace_buffer_lock_reserve  |  +88
  trace_buffer_unlock_commit |  +86
 2 functions changed, 174 bytes added, diff: +174

/tmp/vmlinux.after:
 16 functions changed, 176 bytes added, 413 bytes removed, diff: -237

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:41 +01:00
Arnaldo Carvalho de Melo
0a9877514c ring_buffer: remove unused flags parameter
Impact: API change, cleanup

>From ring_buffer_{lock_reserve,unlock_commit}.

$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
  trace_vprintk              |  -14
  trace_graph_return         |  -14
  trace_graph_entry          |  -10
  trace_function             |   -8
  __ftrace_trace_stack       |   -8
  ftrace_trace_userstack     |   -8
  tracing_sched_switch_trace |   -8
  ftrace_trace_special       |  -12
  tracing_sched_wakeup_trace |   -8
 9 functions changed, 90 bytes removed, diff: -90

linux-2.6-tip/block/blktrace.c:
  __blk_add_trace |   -1
 1 function changed, 1 bytes removed, diff: -1

/tmp/vmlinux.after:
 10 functions changed, 91 bytes removed, diff: -91

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:40 +01:00
Arnaldo Carvalho de Melo
7be421510b trace: Remove unused trace_array_cpu parameter
Impact: cleanup

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 14:35:47 +01:00
Arnaldo Carvalho de Melo
268ccda0cb trace: assign defaults at register_ftrace_event
Impact: simplification of tracers

As all tracers are doing this we might as well do it in
register_ftrace_event and save one branch each time we call these
callbacks.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 14:35:46 +01:00
Arnaldo Carvalho de Melo
ae7462b4f1 trace: make the trace_event callbacks return enum print_line_t
As they actually all return these enumerators.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-04 20:48:39 +01:00
Arnaldo Carvalho de Melo
d9793bd801 trace: judicious error checking of trace_seq results
Impact: bugfix and cleanup

Some callsites were returning either TRACE_ITER_PARTIAL_LINE if the
trace_seq routines (trace_seq_printf, etc) returned 0 meaning its buffer
was full, or zero otherwise.

But...

/* Return values for print_line callback */
enum print_line_t {
        TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
        TRACE_TYPE_HANDLED      = 1,
        TRACE_TYPE_UNHANDLED    = 2     /* Relay to other output functions */
};

In other cases the return value was not being relayed at all.

Most of the time it didn't hurt because the page wasn't get filled, but
for correctness sake, handle the return values everywhere.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-04 20:48:30 +01:00
Arnaldo Carvalho de Melo
939b366977 blktrace: fix coding style in recent patches
Impact: cleanup

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 16:21:34 +01:00
Arnaldo Carvalho de Melo
08a06b83ff blkftrace: binary tracing, synthesizing old format
Impact: new feature

With this and a blkrawverify modified not to verify the sequence numbers
we can start using the userspace tools to verify that the data produced
with the ftrace plugin works as expected.

Example:

[root@f10-1 ~]# echo 1 > /sys/block/sda/sda1/trace/enable
[root@f10-1 ~]# echo bin > /d/tracing/trace_options
[root@f10-1 ~]# echo blk > /d/tracing/current_tracer
[root@f10-1 ~]# cat /d/tracing/trace_pipe > sda1.blktrace.0
^C
[root@f10-1 ~]# ./blkrawverify --noseq sda1
Verifying sda1
    CPU 0
Wrote output to sda1.verify.out
[root@f10-1 ~]# cat sda1.verify.out

---------------
Verifying sda1
    ---------------------
    Summary for cpu 0:
          1349 valid +          0 invalid (100.0%) processed

[root@f10-1 ~]#

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 14:03:53 +01:00
Arnaldo Carvalho de Melo
2c9b238eb3 trace: Change struct trace_event callbacks parameter list
Impact: API change

The trace_seq and trace_entry are in trace_iterator, where there are
more fields that may be needed by tracers, so just pass the
tracer_iterator as is already the case for struct tracer->print_line.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 14:03:52 +01:00
Ingo Molnar
dc573f9b20 Merge branches 'tracing/ftrace', 'tracing/kmemtrace' and 'linus' into tracing/core 2009-02-03 06:25:38 +01:00
Jens Axboe
fb8ec18c31 block: fix oops in blk_queue_io_stat()
Some initial probe requests don't have disk->queue mapped yet, so we
can't rely on a non-NULL queue in blk_queue_io_stat(). Wrap it in
blk_do_io_stat().

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-02 08:42:32 +01:00
Divyesh Shah
3a9a3f6cc5 cfq-iosched: Allow RT requests to pre-empt ongoing BE timeslice
This patch adds the ability to pre-empt an ongoing BE timeslice when a RT
request is waiting for the current timeslice to complete. This reduces the
wait time to disk for RT requests from an upper bound of 4 (current value
of cfq_quantum) to 1 disk request.

Applied Jens' suggeested changes to avoid the rb lookup and use !cfq_class_rt()
and retested.

Latency(secs) for the RT task when doing sequential reads from 10G file.
                       | only RT | RT + BE | RT + BE + this patch
small (512 byte) reads | 143     | 163     | 145
large (1Mb) reads      | 142     | 158     | 146

Signed-off-by: Divyesh Shah <dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:47:33 +01:00
Jens Axboe
bc58ba9468 block: add sysfs file for controlling io stats accounting
This allows us to turn off disk stat accounting completely, for the cases
where the 0.5-1% reduction in system time is important.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:38 +01:00
Jens Axboe
cec0707e40 block: silently error an unsupported barrier bio
This fixes a "regression" from 2.6.28, where the barrier probes that file
systems may do would trigger additional end request warnings in dmesg.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:37 +01:00
Theodore Ts'o
dbdac9b71d block: Fix documentation for blkdev_issue_flush()
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:37 +01:00
Jens Axboe
213d9417fe block: seperate bio/request unplug and sync bits
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:37 +01:00
Bartlomiej Zolnierkiewicz
1308835fff block: export SSD/non-rotational queue flag through sysfs
For some devices (i.e. CFA ATA) we can't reliably detect whether
the device is of rotational or non-rotational type so we need to
leave the final decision about this setting to the user-space.

As a bonus do a minor CodingStyle fixup in queue_nomerges_store().

Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:37 +01:00
Jens Axboe
f48fc4d32e block: get rid of the manual directory counting in blktrace
It can result in a stuck blktrace system, if --kill is used.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:36 +01:00
Martin K. Petersen
322316385d block: Allow empty integrity profile
Allow a block device to allocate and register an integrity profile
without providing a template.  This allows DM to preallocate a profile
to avoid deadlocks during table reconfiguration.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:36 +01:00
Arnaldo Carvalho de Melo
700a3dcb90 blktrace: Use tracing_reset_online_cpus
Impact: cleanup

Use tracing_reset_online_cpus instead of open coding it.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29 14:28:30 +01:00
Arnaldo Carvalho de Melo
32c0bd9624 blktrace: the ftrace interface needs CONFIG_TRACING
Impact: build fix

Also mention in the help text that blktrace now can be used using
the ftrace interface.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-27 14:30:36 +01:00
Arnaldo Carvalho de Melo
157f9c00e8 tracing/blktrace: fix up checkpatch reported problems in ftrace plugin patch
Also make sure sparse (make C=2 block/blktrace.o) is happy too.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-26 18:30:01 +01:00
Arnaldo Carvalho de Melo
c71a896154 blktrace: add ftrace plugin
Impact: New way of using the blktrace infrastructure

This drops the requirement of userspace utilities to use the blktrace
facility.

Configuration is done thru sysfs, adding a "trace" directory to the
partition directory where blktrace can be enabled for the associated
request_queue.

The same filters present in the IOCTL interface are present as sysfs
device attributes.

The /sys/block/sdX/sdXN/trace/enable file allows tracing without any
filters.

The other files in this directory: pid, act_mask, start_lba and end_lba
can be used with the same meaning as with the IOCTL interface.

Using the sysfs interface will only setup the request_queue->blk_trace
fields, tracing will only take place when the "blk" tracer is selected
via the ftrace interface, as in the following example:

To see the trace, one can use the /d/tracing/trace file or the
/d/tracign/trace_pipe file, with semantics defined in the ftrace
documentation in Documentation/ftrace.txt.

[root@f10-1 ~]# cat /t/trace
       kjournald-305   [000]  3046.491224:   8,1    A WBS 6367 + 8 <- (8,1) 6304
       kjournald-305   [000]  3046.491227:   8,1    Q   R 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491236:   8,1    G  RB 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491239:   8,1    P  NS [kjournald]
       kjournald-305   [000]  3046.491242:   8,1    I RBS 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491251:   8,1    D  WB 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491610:   8,1    U  WS [kjournald] 1
          <idle>-0     [000]  3046.511914:   8,1    C  RS 6367 + 8 [6367]
[root@f10-1 ~]#

The default line context (prefix) format is the one described in the ftrace
documentation, with the blktrace specific bits using its existing format,
described in blkparse(8).

If one wants to have the classic blktrace formatting, this is possible by
using:

[root@f10-1 ~]# echo blk_classic > /t/trace_options
[root@f10-1 ~]# cat /t/trace
  8,1    0  3046.491224   305  A WBS 6367 + 8 <- (8,1) 6304
  8,1    0  3046.491227   305  Q   R 6367 + 8 [kjournald]
  8,1    0  3046.491236   305  G  RB 6367 + 8 [kjournald]
  8,1    0  3046.491239   305  P  NS [kjournald]
  8,1    0  3046.491242   305  I RBS 6367 + 8 [kjournald]
  8,1    0  3046.491251   305  D  WB 6367 + 8 [kjournald]
  8,1    0  3046.491610   305  U  WS [kjournald] 1
  8,1    0  3046.511914     0  C  RS 6367 + 8 [6367]
[root@f10-1 ~]#

Using the ftrace standard format allows more flexibility, such
as the ability of asking for backtraces via trace_options:

[root@f10-1 ~]# echo noblk_classic > /t/trace_options
[root@f10-1 ~]# echo stacktrace > /t/trace_options

[root@f10-1 ~]# cat /t/trace
       kjournald-305   [000]  3318.826779:   8,1    A WBS 6375 + 8 <- (8,1) 6312
       kjournald-305   [000]  3318.826782:
 <= submit_bio
 <= submit_bh
 <= sync_dirty_buffer
 <= journal_commit_transaction
 <= kjournald
 <= kthread
 <= child_rip
       kjournald-305   [000]  3318.826836:   8,1    Q   R 6375 + 8 [kjournald]
       kjournald-305   [000]  3318.826837:
 <= generic_make_request
 <= submit_bio
 <= submit_bh
 <= sync_dirty_buffer
 <= journal_commit_transaction
 <= kjournald
 <= kthread

Please read the ftrace documentation to use aditional, standardized
tracing filters such as /d/tracing/trace_cpumask, etc.

See also /d/tracing/trace_mark to add comments in the trace stream,
that is equivalent to the /d/block/sdaN/msg interface.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-26 14:40:53 +01:00
Linus Torvalds
2150edc6c5 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (57 commits)
  jbd2: Fix oops in jbd2_journal_init_inode() on corrupted fs
  ext4: Remove "extents" mount option
  block: Add Kconfig help which notes that ext4 needs CONFIG_LBD
  ext4: Make printk's consistently prefixed with "EXT4-fs: "
  ext4: Add sanity checks for the superblock before mounting the filesystem
  ext4: Add mount option to set kjournald's I/O priority
  jbd2: Submit writes to the journal using WRITE_SYNC
  jbd2: Add pid and journal device name to the "kjournald2 starting" message
  ext4: Add markers for better debuggability
  ext4: Remove code to create the journal inode
  ext4: provide function to release metadata pages under memory pressure
  ext3: provide function to release metadata pages under memory pressure
  add releasepage hooks to block devices which can be used by file systems
  ext4: Fix s_dirty_blocks_counter if block allocation failed with nodelalloc
  ext4: Init the complete page while building buddy cache
  ext4: Don't allow new groups to be added during block allocation
  ext4: mark the blocks/inode bitmap beyond end of group as used
  ext4: Use new buffer_head flag to check uninit group bitmaps initialization
  ext4: Fix the race between read_inode_bitmap() and ext4_new_inode()
  ext4: code cleanup
  ...
2009-01-08 17:14:59 -08:00
Linus Torvalds
cd764695b6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (45 commits)
  [SCSI] qla2xxx: Update version number to 8.03.00-k1.
  [SCSI] qla2xxx: Add ISP81XX support.
  [SCSI] qla2xxx: Use proper request/response queues with MQ instantiations.
  [SCSI] qla2xxx: Correct MQ-chain information retrieval during a firmware dump.
  [SCSI] qla2xxx: Collapse EFT/FCE copy procedures during a firmware dump.
  [SCSI] qla2xxx: Don't pollute kernel logs with ZIO/RIO status messages.
  [SCSI] qla2xxx: Don't fallback to interrupt-polling during re-initialization with MSI-X enabled.
  [SCSI] qla2xxx: Remove support for reading/writing HW-event-log.
  [SCSI] cxgb3i: add missing include
  [SCSI] scsi_lib: fix DID_RESET status problems
  [SCSI] fc transport: restore missing dev_loss_tmo callback to LLDD
  [SCSI] aha152x_cs: Fix regression that keeps driver from using shared interrupts
  [SCSI] sd: Correctly handle 6-byte commands with DIX
  [SCSI] sd: DIF: Fix tagging on platforms with signed char
  [SCSI] sd: DIF: Show app tag on error
  [SCSI] Fix error handling for DIF/DIX
  [SCSI] scsi_lib: don't decrement busy counters when inserting commands
  [SCSI] libsas: fix test for negative unsigned and typos
  [SCSI] a2091, gvp11: kill warn_unused_result warnings
  [SCSI] fusion: Move a dereference below a NULL test
  ...

Fixed up trivial conflict due to moving the async part of sd_probe
around in the async probes vs using dev_set_name() in naming.
2009-01-08 16:27:31 -08:00
Theodore Ts'o
4d783b093c block: Add Kconfig help which notes that ext4 needs CONFIG_LBD
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jens Axboe <jens.axboe@oracle.com>
2009-01-06 15:16:33 -05:00
Kay Sievers
3ada8b7e98 block: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-01-06 10:44:43 -08:00
FUJITA Tomonori
97ae77a1cd [SCSI] block: make blk_rq_map_user take a NULL user-space buffer for WRITE
The commit 818827669d (block: make
blk_rq_map_user take a NULL user-space buffer) extended
blk_rq_map_user to accept a NULL user-space buffer with a READ
command. It was necessary to convert sg to use the block layer mapping
API.

This patch extends blk_rq_map_user again for a WRITE command. It is
necessary to convert st and osst drivers to use the block layer
apping API.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-01-02 11:10:35 -06:00
FUJITA Tomonori
56c451f4b5 [SCSI] block: fix the partial mappings with struct rq_map_data
This fixes bio_copy_user_iov to properly handle the partial mappings
with struct rq_map_data (which only sg uses for now but st and osst
will shortly). It adds the offset member to struct rq_map_data and
changes blk_rq_map_user to update it so that bio_copy_user_iov can add
an appropriate page frame via bio_add_pc_page().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-01-02 11:10:08 -06:00
Rusty Russell
2ca1a61583 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:

	arch/x86/kernel/io_apic.c
2008-12-31 23:05:57 +10:30
Rusty Russell
33edcf133b Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2008-12-30 08:02:35 +10:30
Jens Axboe
62c1fe9d9f cfq-iosched: fix race between exiting queue and exiting task
Original patch from Nikanth Karthikesan <knikanth@suse.de>

When a queue exits the queue lock is taken and cfq_exit_queue() would free all
the cic's associated with the queue.

But when a task exits, cfq_exit_io_context() gets cic one by one and then
locks the associated queue to call __cfq_exit_single_io_context. It looks like
between getting a cic from the ioc and locking the queue, the queue might have
exited on another cpu.

Fix this by rechecking the cfq_io_context queue key inside the queue lock
again, and not calling into __cfq_exit_single_io_context() if somebody
beat us to it.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:52 +01:00
Jens Axboe
b3a6ffe16b Get rid of CONFIG_LSF
We have two seperate config entries for large devices/files. One
is CONFIG_LBD that guards just the devices, the other is CONFIG_LSF
that handles large files. This doesn't make a lot of sense, you typically
want both or none. So get rid of CONFIG_LSF and change CONFIG_LBD wording
to indicate that it covers both.

Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:51 +01:00
Roel Kluin
3c18ce71af block: make blk_softirq_init() static
Sparse asked whether these could be static.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:51 +01:00
FUJITA Tomonori
18af8b2ca3 block: use min_not_zero in blk_queue_stack_limits
zero is invalid for max_phys_segments, max_hw_segments, and
max_segment_size. It's better to use use min_not_zero instead of
min. min() works though (because the commit 0e435ac makes sure that
these values are set to the default values, non zero, if a queue is
initialized properly).

With this patch, blk_queue_stack_limits does the almost same thing
that dm's combine_restrictions_low() does. I think that it's easy to
remove dm's combine_restrictions_low.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:51 +01:00
Jens Axboe
a6f23657d3 block: add one-hit cache for disk partition lookup
disk_map_sector_rcu() returns a partition from a sector offset,
which we use for IO statistics on a per-partition basis. The
lookup itself is an O(N) list lookup, where N is the number of
partitions. This actually hurts performance quite a bit, even
on the lower end partitions. On higher numbered partitions,
it can get pretty bad.

Solve this by adding a one-hit cache for partition lookup.
This makes the lookup O(1) for the case where we do most IO to
one partition. Even for mixed partition workloads, amortized cost
is pretty close to O(1) since the natural IO batching makes the
one-hit cache last for lots of IOs.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:51 +01:00
Jens Axboe
30e0dc28bf cfq-iosched: remove limit of dispatch depth of max 4 times quantum
This basically limits the hardware queue depth to 4*quantum at any
point in time, which is 16 with the default settings. As CFQ uses
other means to shrink the hardware queue when necessary in the first
place, there's really no need for this extra heuristic. Additionally,
it ends up hurting performance in some cases.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:51 +01:00
Jens Axboe
b374d18a4b block: get rid of elevator_t typedef
Just use struct elevator_queue everywhere instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:29:50 +01:00
Jens Axboe
a31a97381c block: don't use plugging on SSD devices
We just want to hand the first bits of IO to the device as fast
as possible. Gains a few percent on the IOPS rate.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:28:45 +01:00
Tejun Heo
a185eb4bc8 block: fix empty barrier on write-through w/ ordered tag
Empty barrier on write-through (or no cache) w/ ordered tag has no
command to execute and without any command to execute ordered tag is
never issued to the device and the ordering is never achieved.  Force
draining for such cases.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:28:45 +01:00
Tejun Heo
58eea927d2 block: simplify empty barrier implementation
Empty barrier required special handling in __elv_next_request() to
complete it without letting the low level driver see it.

With previous changes, barrier code is now flexible enough to skip the
BAR step using the same barrier sequence selection mechanism.  Drop
the special handling and mask off q->ordered from start_ordered().

Remove blk_empty_barrier() test which now has no user.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:28:45 +01:00
Tejun Heo
8f11b3e99a block: make barrier completion more robust
Barrier completion had the following assumptions.

* start_ordered() couldn't finish the whole sequence properly.  If all
  actions are to be skipped, q->ordseq is set correctly but the actual
  completion was never triggered thus hanging the barrier request.

* Drain completion in elv_complete_request() assumed that there's
  always at least one request in the queue when drain completes.

Both assumptions are true but these assumptions need to be removed to
improve empty barrier implementation.  This patch makes the following
changes.

* Make start_ordered() use blk_ordered_complete_seq() to mark skipped
  steps complete and notify __elv_next_request() that it should fetch
  the next request if the whole barrier has completed inside
  start_ordered().

* Make drain completion path in elv_complete_request() check whether
  the queue is empty.  Empty queue also indicates drain completion.

* While at it, convert 0/1 return from blk_do_ordered() to false/true.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:28:45 +01:00
Tejun Heo
f671620e7d block: make every barrier action optional
In all barrier sequences, the barrier write itself was always assumed
to be issued and thus didn't have corresponding control flag.  This
patch adds QUEUE_ORDERED_DO_BAR and unify action mask handling in
start_ordered() such that any barrier action can be skipped.

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-29 08:28:45 +01:00