Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.
Patched with:
git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
dget_locked was a shortcut to avoid the lazy lru manipulation when we already
held dcache_lock (lru manipulation was relatively cheap at that point).
However, how that the lru lock is an innermost one, we never hold it at any
caller, so the lock cost can now be avoided. We already have well working lazy
dcache LRU, so it should be fine to defer LRU manipulations to scan time.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
The remaining usages for dcache_lock is to allow atomic, multi-step read-side
operations over the directory tree by excluding modifications to the tree.
Also, to walk in the leaf->root direction in the tree where we don't have
a natural d_lock ordering.
This could be accomplished by taking every d_lock, but this would mean a
huge number of locks and actually gets very tricky.
Solve this instead by using the rename seqlock for multi-step read-side
operations, retry in case of a rename so we don't walk up the wrong parent.
Concurrent dentry insertions are not serialised against. Concurrent deletes
are tricky when walking up the directory: our parent might have been deleted
when dropping locks so also need to check and retry for that.
We can also use the rename lock in cases where livelock is a worry (and it
is introduced in subsequent patch).
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Protect d_subdirs and d_child with d_lock, except in filesystems that aren't
using dcache_lock for these anyway (eg. using i_mutex).
Note: if we change the locking rule in future so that ->d_child protection is
provided only with ->d_parent->d_lock, it may allow us to reduce some locking.
But it would be an exception to an otherwise regular locking scheme, so we'd
have to see some good results. Probably not worthwhile.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_compare so it may be called from lock-free RCU lookups. This
does put significant restrictions on what may be done from the callback,
however there don't seem to have been any problems with in-tree fses.
If some strange use case pops up that _really_ cannot cope with the
rcu-walk rules, we can just add new rcu-unaware callbacks, which would
cause name lookup to drop out of rcu-walk mode.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
smpfs and ncpfs want to update a live dentry name in-place. Rather than
have them open code the locking, provide a documented dcache API.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_delete from a dentry deletion notification to a dentry caching
advise, more like ->drop_inode. Require it to be constant and idempotent,
and not take d_lock. This is how all existing filesystems use the callback
anyway.
This makes fine grained dentry locking of dput and dentry lru scanning
much simpler.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
This reverts commit 7e24cce38a because it
was never appropriate for mainline.
Do not check for init flag before starting I/O - zram module is unusable
without this fix.
The oops mentioned in the reverted commit message was actually a problem
only with the zram version as present in project's own repository where
we allocate struct zram_stats_cpu upon device initialization. OTOH, In
mainline/staging version of zram, we allocate struct stats upfront, so
this oops cannot happen in mainline version.
Checking for init_done flag in zram_make_request() results in a *no-op*
for any I/O operation since we simply always return success. This flag
is actually set when the first write occurs on a zram disk which
triggers its initialization.
Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=25722
Reported-by: Dennis Jansen <dennis.jansen@web.de>
Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6:
[media] gspca - sonixj: Better handling of the bridge registers 0x01 and 0x17
[media] gspca - sonixj: Add the bit definitions of the bridge reg 0x01 and 0x17
[media] gspca - sonixj: Set the flag for some devices
[media] gspca - sonixj: Add a flag in the driver_info table
[media] gspca - sonixj: Fix a bad probe exchange
[media] gspca - sonixj: Move bridge init to sd start
[media] bttv: remove unneeded locking comments
[media] bttv: fix mutex use before init (BZ#24602)
[media] Don't export format_by_forcc on two different drivers
* 'staging-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6: (27 commits)
Staging: rt2870: Add USB ID for Buffalo Airstation WLI-UC-GN
staging: easycap needs smp_lock.h, fixes build error
Staging: batman-adv: ensure that eth_type_trans gets linear memory
Staging: batman-adv: Don't remove interface with spinlock held
staging: brcm80211: updated maintainers contact information
staging: fix winbond build, needs delay.h
Staging: line6: fix up my fixup for some sysfs attribute permissions
Staging: zram: fix up my fixup for some sysfs attribute permissions
Staging: udlfb: fix up my fixup for some sysfs attribute permissions
Staging: samsung-laptop: fix up my fixup for some sysfs attribute permissions
Staging: iio: adis16220: fix up my fixup for some sysfs attribute permissions
Staging: frontier: fix up my fixup for some sysfs attribute permissions
Staging: asus_oled: fix up my fixup for some sysfs attribute permissions
staging: spectra: fix build error
Staging: intel_sst: fix memory leak
Staging: rtl8712: signedness bug in init
staging: rtl8187se: Change panic to warn when RF switch turned off
staging: comedi: fix memory leak
Staging: quickstart: free after input_unregister_device()
Staging: speakup: free after input_unregister_device()
...
Drivers should append their name on exported symbols, to avoid
conflicts with allyesconfig:
drivers/staging/built-in.o: In function `format_by_fourcc':
/home/v4l/work_trees/linus/drivers/staging/cx25821/cx25821-video.c:96: multiple definition of `format_by_fourcc'
drivers/media/built-in.o:/home/v4l/work_trees/linus/drivers/media/common/saa7146_video.c:88: first defined here
Let's rename both occurences with a small shellscript:
for i in drivers/staging/cx25821/*.[ch]; do sed s,format_by_fourcc,cx25821_format_by_fourcc,g <$i >a && mv a $i; done
for i in drivers/media/common/saa7146*.[ch]; do sed s,format_by_fourcc,saa7146_format_by_fourcc,g <$i >a && mv a $i; done
for i in include/media/saa7146*.[ch]; do sed s,format_by_fourcc,saa7146_format_by_fourcc,g <$i >a && mv a $i; done
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
BugLink: http://bugs.launchpad.net/bugs/441990
This was tested to successfully enable the hardware.
Signed-off-by: John Tapsell <johnflux@gmail.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
CC: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
eth_type_trans tries to pull data with the length of the ethernet header
from the skb. We only ensured that enough data for the first ethernet
header and the batman header is available in non-paged memory of the skb
and not for the ethernet after the batman header.
eth_type_trans would fail sometimes with drivers which don't ensure that
all there data is perfectly linearised.
The failure was noticed through a kernel bug Oops generated by the
skb_pull inside eth_type_trans.
Reported-by: Rafal Lesniak <lesniak@eresi-project.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We call a lot of the netdevice code when holding if_list_lock which will
spin the whole time. This is not necessary because we only want to
protect the access to the list to be serialized. An extra queue can be
used which hold all interfaces which should be removed and then use that
queue without any locks for netdevice cleanup.
We create a "scheduling while atomic" Oops when calling different
netdevice related functions inside a spinlock protected area on a
preemtible kernel.
Reported-by: Rafal Lesniak <lesniak@eresi-project.org>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Open-source development team extended so contacts updated.
Reviewed-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The argument isn't used anymore by the functions, remove it.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
winbond drivers use msleep() and delay(), so include linux/delay.h
in a common header file to prevent build errors.
drivers/staging/winbond/phy_calibration.c:987: error: implicit declaration of function 'msleep'
drivers/staging/winbond/phy_calibration.c:1556: error: implicit declaration of function 'udelay'
drivers/staging/winbond/reg.c:894: error: implicit declaration of function 'msleep'
drivers/staging/winbond/reg.c:1178: error: implicit declaration of function 'udelay'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Kernel build fail for cx25821-video has depends on smp_lock.h header
file, but the dependency is removed in recent commit 451a3c24b0.
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Markus Grabner <grabner@icg.tugraz.at>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Barry Song <Barry.Song@analog.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: David Taht <d@teklibre.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should be writable by root, not readable.
Doh, stupid me with the wrong flags.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Jakub Schmidtke <sjakub@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
blk_queue_ordered() has been deprecated and replaced with
blk_queue_flush() by Tejun. However, use of blk_queue_ordered()
in spectra nand driver has not been converted yet and thus results
in the following build error.
drivers/staging/spectra/ffsport.c: In function SBD_setup_device:
drivers/staging/spectra/ffsport.c:659: error: implicit declaration of function blk_queue_ordered
drivers/staging/spectra/ffsport.c:659: error: QUEUE_ORDERED_DRAIN_FLUSH undeclared (first use in this function)
drivers/staging/spectra/ffsport.c:659: error: (Each undeclared identifier is reported only once
drivers/staging/spectra/ffsport.c:659: error: for each function it appears in.)
Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The big kernel lock has been removed from all these files at some point,
leaving only the #include.
Remove this too as a cleanup.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The stradis driver is on its way out, but it should still be marked
correctly as depending on the big kernel lock. It could easily be
changed to not require it if someone decides to revive the driver and
port it to v4l2 in the process.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Sedat Dilek <sedat.dilek@googlemail.com>
Cc: Nathan Laredo <laredo@gnu.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.
The patch below presents a simple SCSI host lock push-down as an
equivalent transformation. No locking or other behavior should change
with this patch. All existing bugs and locking orders are preserved.
Additionally, add one parameter to queuecommand,
struct Scsi_Host *
and remove one parameter from queuecommand,
void (*done)(struct scsi_cmnd *)
Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.
Minimal code disturbance was attempted with this change. Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The original code set "str_info->decode_ibuf" to NULL so the kfree() is
no-op.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Harsha Priya <priya.harsha@intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
PollingCnt is 20 and that means we loop 20 times and then run the
timeout code. After the end of the loop PollingCnt should be -1 but
because it's an unsigned char, it's actually 255 and the timeout
code never runs.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This driver issues a kernel panic over conditions that do not
justify such drastic action. Change these to log entries with
a stack dump.
This patch fixes the system crash reported in
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/674285.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-and-Tested-by: Robie Basik <rb-oss-3@justgohome.co.uk>
Cc: Stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
input_unregister_device() releases "quickstart_input" so the
input_free_device() is a double free. Also I noticed that there is a
memory leak if the call to input_register_device() fails.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
input_unregister_device() frees the device so the call to
input_free_device() is a double free.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Markus Grabner <grabner@icg.tugraz.at>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Barry Song <Barry.Song@analog.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Taht <d@teklibre.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They should not be writable by any user
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jakub Schmidtke <sjakub@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Nick Piggin