Geert, my crosstool don't produce warning below. I guess this has to do
something with compiler version.
- Geert noticed following warning during compilation.
drivers/block/amiflop.c:1344: warning: ‘rq’ may be used uninitialized in
this function
drivers/block/ataflop.c:1402: warning: ‘rq’ may be used uninitialized in
this function
- Initialize rq to NULL to fix the warning. If we can't find a suitable request
to dispatch, this function should return NULL instead of a possibly garbage
pointer.
- Cross compile tested only. Don't have hardware to test it.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
REQ_HARDBARRIER is dead now, so remove the leftovers. What's left
at this point is:
- various checks inside the block layer.
- sanity checks in bio based drivers.
- now unused bio_empty_barrier helper.
- Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while,
but Xen really needs to sort out it's barrier situaton.
- setting of ordered tags in uas - dead code copied from old scsi
drivers.
- scsi different retry for barriers - it's dead and should have been
removed when flushes were converted to FS requests.
- blktrace handling of barriers - removed. Someone who knows blktrace
better should add support for REQ_FLUSH and REQ_FUA, though.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Convert direct reads of an inode's i_size to using i_size_read().
i_size_{read,write} use a seqcount to protect reads from accessing
incomple writes. Concurrent i_size_write()s require mutual exclussion
to protect the seqcount that is used by i_size_{read,write}. But
i_size_read() callers do not need to use additional locking.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: NeilBrown <neilb@suse.de>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Commit 488211844e ("floppy: switch to one queue per drive instead of
sharing a queue") introduced a use-after-free. We do "put_disk()" on
the disk device _before_ we then clean up the queue associated with that
disk.
Move the put_disk() down to avoid dereferencing a free'd data structure.
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Reported-and-tested-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some(?) Xen block backends fail BLKIF_OP_WRITE_BARRIER requests, which
Linux uses as a cache flush operation. In that case, disable use
of FLUSH.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Daniel Stodden <daniel.stodden@citrix.com>
The BLKIF_OP_WRITE_BARRIER is a full ordered barrier, so we can use it
to implement FUA as well as a plain FLUSH.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Implement a flush as a full barrier, since we have nothing weaker.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Christoph Hellwig <hch@lst.de>
and branch 'for-linus' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm
* 'for-linus' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
xen: register xen pci notifier
xen: initialize cpu masks for pv guests in xen_smp_init
xen: add a missing #include to arch/x86/pci/xen.c
xen: mask the MTRR feature from the cpuid
xen: make hvc_xen console work for dom0.
xen: add the direct mapping area for ISA bus access
xen: Initialize xenbus for dom0.
xen: use vcpu_ops to setup cpu masks
xen: map a dummy page for local apic and ioapic in xen_set_fixmap
xen: remap MSIs into pirqs when running as initial domain
xen: remap GSIs as pirqs when running as initial domain
xen: introduce XEN_DOM0 as a silent option
xen: map MSIs into pirqs
xen: support GSI -> pirq remapping in PV on HVM guests
xen: add xen hvm acpi_register_gsi variant
acpi: use indirect call to register gsi in different modes
xen: implement xen_hvm_register_pirq
xen: get the maximum number of pirqs from xen
xen: support pirq != irq
* 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (27 commits)
X86/PCI: Remove the dependency on isapnp_disable.
xen: Update Makefile with CONFIG_BLOCK dependency for biomerge.c
MAINTAINERS: Add myself to the Xen Hypervisor Interface and remove Chris Wright.
x86: xen: Sanitse irq handling (part two)
swiotlb-xen: On x86-32 builts, select SWIOTLB instead of depending on it.
MAINTAINERS: Add myself for Xen PCI and Xen SWIOTLB maintainer.
xen/pci: Request ACS when Xen-SWIOTLB is activated.
xen-pcifront: Xen PCI frontend driver.
xenbus: prevent warnings on unhandled enumeration values
xenbus: Xen paravirtualised PCI hotplug support.
xen/x86/PCI: Add support for the Xen PCI subsystem
x86: Introduce x86_msi_ops
msi: Introduce default_[teardown|setup]_msi_irqs with fallback.
x86/PCI: Export pci_walk_bus function.
x86/PCI: make sure _PAGE_IOMAP it set on pci mappings
x86/PCI: Clean up pci_cache_line_size
xen: fix shared irq device passthrough
xen: Provide a variant of xen_poll_irq with timeout.
xen: Find an unbound irq number in reverse order (high to low).
xen: statically initialize cpu_evtchn_mask_p
...
Fix up trivial conflicts in drivers/pci/Makefile
This patch removes the controller overlap between cciss and hpsa. It was
decided that no overlap should exist. All new controllers will use the hpsa
SCSI based driver.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Structure IOCTL_Command_struct is copied to userland with
some padding fields at the end of the struct unitialized.
It leads to leaking of contents of kernel stack memory.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
As described in https://bugzilla.kernel.org/show_bug.cgi?id=19922
: I had an AoE device go down overnight, and while a server was trying to
: write to it, it was also writing this message to its logs:
:
: 209 printk(KERN_INFO "aoe: device %ld.%d is not up\n",
: 210 d->aoemajor, d->aoeminor);
:
: The message appeared many times per second, and over several hours
: produced about 7.5 gigabytes of log files, filling up all free space on
: the root filesystem.
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Suggested-by: Roman Mamedov <roman@rm.pp.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
If CONFIG_LBDAF=y, `sector_t' becomes `u64' instead of `unsigned long':
drivers/block/z2ram.c: In function ¡do_z2_request¢:
drivers/block/z2ram.c:83: warning: format %lu expects type `long unsigned int', but argument 2 has type `sector_t'
Hence always cast it to `unsigned long long' for printing. Also do the
pr_err() dance, while we're at it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
flush_scheduled_work() is deprecated and scheduled to be removed.
Directly cancel aoedev->work on free instead of depending on
flush_scheduled_works().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Failure to create drbd_ee_mempool appears not to get checked. Looks like
a copy-and-paste problem to me.
Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
In autoclear mode bdev is NULL but the sysfs
entry should be destroyed otherwise this warning appears:
WARNING: at fs/sysfs/dir.c:451 sysfs_add_one+0x82/0x95()
sysfs: cannot create duplicate filename '/devices/virtual/block/loop0/loop'
Fixes commit ee86273062
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Ensure kmap_atomic() usage is strictly nested
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6:
mtd/m25p80: add support to parse the partitions by OF node
of/irq: of_irq.c needs to include linux/irq.h
of/mips: Cleanup some include directives/files.
of/mips: Add device tree support to MIPS
of/flattree: Eliminate need to provide early_init_dt_scan_chosen_arch
of/device: Rework to use common platform_device_alloc() for allocating devices
of/xsysace: Fix OF probing on little-endian systems
of: use __be32 types for big-endian device tree data
of/irq: remove references to NO_IRQ in drivers/of/platform.c
of/promtree: add package-to-path support to pdt
of/promtree: add of_pdt namespace to pdt code
of/promtree: no longer call prom_ functions directly; use an ops structure
of/promtree: make drivers/of/pdt.c no longer sparc-only
sparc: break out some PROM device-tree building code out into drivers/of
of/sparc: convert various prom_* functions to use phandle
sparc: stop exporting openprom.h header
powerpc, of_serial: Endianness issues setting up the serial ports
of: MTD: Fix OF probing on little-endian systems
of: GPIO: Fix OF probing on little-endian systems
We would prefer not to have any overlap between the two drivers.
Remove the cciss_allow_hpsa option, as it it is no longer needed.
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This is to conserve memory in a memory-limited kdump scenario
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
and use the doorbell reset method if available (which doesn't
lock up the controller if you properly save and restore all
the PCI registers that you're supposed to.)
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
After a reset, we should first wait for the board to become "not ready",
and then wait for it to become "ready", instead of immediately
waiting for it to become "ready", and do this waiting *after*
restoring PCI config space registers.
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (141 commits)
USB: mct_u232: fix broken close
USB: gadget: amd5536udc.c: fix error path
USB: imx21-hcd - fix off by one resource size calculation
usb: gadget: fix Kconfig warning
usb: r8a66597-udc: Add processing when USB was removed.
mxc_udc: add workaround for ENGcm09152 for i.MX35
USB: ftdi_sio: add device ids for ScienceScope
USB: musb: AM35x: Workaround for fifo read issue
USB: musb: add musb support for AM35x
USB: AM35x: Add musb support
usb: Fix linker errors with CONFIG_PM=n
USB: ohci-sh - use resource_size instead of defining its own resource_len macro
USB: isp1362-hcd - use resource_size instead of defining its own resource_len macro
USB: isp116x-hcd - use resource_size instead of defining its own resource_len macro
USB: xhci: Fix compile error when CONFIG_PM=n
USB: accept some invalid ep0-maxpacket values
USB: xHCI: PCI power management implementation
USB: xHCI: bus power management implementation
USB: xHCI: port remote wakeup implementation
USB: xHCI: port power management implementation
...
Manually fix up (non-data) conflict: the SCSI merge gad renamed the
'hw_sector_size' member to 'physical_block_size', and the USB tree
brought a new use of it.
* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
xen-blkfront: disable barrier/flush write support
Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
block: remove BLKDEV_IFL_WAIT
aic7xxx_old: removed unused 'req' variable
block: remove the BH_Eopnotsupp flag
block: remove the BLKDEV_IFL_BARRIER flag
block: remove the WRITE_BARRIER flag
swap: do not send discards as barriers
fat: do not send discards as barriers
ext4: do not send discards as barriers
jbd2: replace barriers with explicit flush / FUA usage
jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
jbd: replace barriers with explicit flush / FUA usage
nilfs2: replace barriers with explicit flush / FUA usage
reiserfs: replace barriers with explicit flush / FUA usage
gfs2: replace barriers with explicit flush / FUA usage
btrfs: replace barriers with explicit flush / FUA usage
xfs: replace barriers with explicit flush / FUA usage
block: pass gfp_mask and flags to sb_issue_discard
dm: convey that all flushes are processed as empty
...
* 'for-2.6.37/drivers' of git://git.kernel.dk/linux-2.6-block: (95 commits)
cciss: fix PCI IDs for new Smart Array controllers
drbd: add race-breaker to drbd_go_diskless
drbd: use dynamic_dev_dbg to optionally log uuid changes
dynamic_debug.h: Fix dynamic_dev_dbg() macro if CONFIG_DYNAMIC_DEBUG not set
drbd: cleanup: change "<= 0" to "== 0"
drbd: relax the grace period of the md_sync timer again
drbd: add some more explicit drbd_md_sync
drbd: drop wrong debug asserts, fix recently introduced race
drbd: cleanup useless leftover warn/error printk's
drbd: add explicit drbd_md_sync to drbd_resync_finished
drbd: Do not log an ASSERT for P_OV_REQUEST packets while C_CONNECTED
drbd: fix for possible deadlock on IO error during resync
drbd: fix unlikely access after free and list corruption
drbd: fix for spurious fullsync (uuids rotated too fast)
drbd: allow for explicit resync-finished notifications
drbd: preparation commit, using full state in receive_state()
drbd: drbd_send_ack_dp must not rely on header information
drbd: Fix regression in recv_bm_rle_bits (compressed bitmap)
drbd: Fixed a stupid copy and paste error
drbd: Allow larger values for c-fill-target.
...
Fix up trivial conflict in drivers/block/ataflop.c due to BKL removal
* 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block: (39 commits)
cfq-iosched: Fix a gcc 4.5 warning and put some comments
block: Turn bvec_k{un,}map_irq() into static inline functions
block: fix accounting bug on cross partition merges
block: Make the integrity mapped property a bio flag
block: Fix double free in blk_integrity_unregister
block: Ensure physical block size is unsigned int
blkio-throttle: Fix possible multiplication overflow in iops calculations
blkio-throttle: limit max iops value to UINT_MAX
blkio-throttle: There is no need to convert jiffies to milli seconds
blkio-throttle: Fix link failure failure on i386
blkio: Recalculate the throttled bio dispatch time upon throttle limit change
blkio: Add root group to td->tg_list
blkio: deletion of a cgroup was causes oops
blkio: Do not export throttle files if CONFIG_BLK_DEV_THROTTLING=n
block: set the bounce_pfn to the actual DMA limit rather than to max memory
block: revert bad fix for memory hotplug causing bounces
Fix compile error in blk-exec.c for !CONFIG_DETECT_HUNG_TASK
block: set the bounce_pfn to the actual DMA limit rather than to max memory
block: Prevent hang_check firing during long I/O
cfq: improve fsync performance for small files
...
Fix up trivial conflicts due to __rcu sparse annotation in include/linux/genhd.h
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
vfs: make no_llseek the default
vfs: don't use BKL in default_llseek
llseek: automatically add .llseek fop
libfs: use generic_file_llseek for simple_attr
mac80211: disallow seeks in minstrel debug code
lirc: make chardev nonseekable
viotape: use noop_llseek
raw: use explicit llseek file operations
ibmasmfs: use generic_file_llseek
spufs: use llseek in all file operations
arm/omap: use generic_file_llseek in iommu_debug
lkdtm: use generic_file_llseek in debugfs
net/wireless: use generic_file_llseek in debugfs
drm: use noop_llseek
* 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
block: autoconvert trivial BKL users to private mutex
drivers: autoconvert trivial BKL users to private mutex
ipmi: autoconvert trivial BKL users to private mutex
mac: autoconvert trivial BKL users to private mutex
mtd: autoconvert trivial BKL users to private mutex
scsi: autoconvert trivial BKL users to private mutex
Fix up trivial conflicts (due to addition of private mutex right next to
deletion of a version string) in drivers/char/pcmcia/cm40[04]0_cs.c
This commit changes prefix for some of the USB mass storage
class related macros (ie. USB_SC_ for subclass and USB_PR_
for class).
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
That assertion's condition needed adjustment for today's semantics
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
If we don't rate limit it, and you happen to log err level messages via
serial console, an IO error on a disconnected Primary may cause serious
unresponsiveness.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This codepath used to be called only for failed kmalloc GFP_ATOMIC,
but is now also triggered by other things.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
If we get an IO-error during an activity log transaction,
if we failed to write the bitmap of the evicted extent,
we must not write the transaction itself.
If we failed to write the transaction,
we must not even submit the corresponding bio,
as its extent is not yet marked in the activity log.
Otherwise, if this was a disconneted Primary (degraded cluster), which
now lost its disk as well, and we later re-attach the same backend
storage, we possibly "forget" to resync some parts of the disk that
potentially have been changed.
On the receiving side, when receiving from a peer with unhealthy disk,
checking for pdsk == D_DISKLESS is not enough, we need to set out of
sync and do AL transactions for everything pdsk < D_INCONSISTENT on the
receiving side.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
If we have contention in drbd_al_begin_iod (heavy randon IO),
an administrative request to detach the disk may deadlock
for similar reasons as the recently fixed deadlock if detaching
because of IO-error.
The approach taken here is to either go through the intermediate
cleanup state D_FAILED, or first lock out application io,
don't just go directly to D_DISKLESS.
We need an additional state bit (WAS_IO_ERROR) to distinguish
the -> D_FAILED because of IO-error from other failures.
Sanitize D_ATTACHING -> D_FAILED to D_ATTACHING -> D_DISKLESS.
If only attaching, ldev may be missing still, but would be referenced
from within the after_state_ch for -> D_FAILED, potentially
dereferencing a NULL pointer.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
If those messages ever get logged, clearly state that they are
actually failed ASSERTS, so our regression tests can pick them up
from the logs more easily.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Every code path changing the current UUID needs to get it on stable
storage anyways. Flush it to disk right there, remove the now obsolte
explicit drbd_md_sync statements in the other code paths.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
* 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
virtio_blk: remove BKL leftovers
virtio: console: Disable lseek(2) for port file operations
virtio: console: Send SIGIO in case of port unplug
virtio: console: Send SIGIO on new data arrival on ports
virtio: console: Send SIGIO to processes that request it for host events
virtio: console: Reference counting portdev structs is not needed
virtio: console: Add reference counting for port struct
virtio: console: Use cdev_alloc() instead of cdev_init()
virtio: console: Add a find_port_by_devt() function
virtio: console: Add a list of portdevs that are active
virtio: console: open: Use a common path for error handling
virtio: console: remove_port() should return void
virtio: console: Make write() return -ENODEV on hot-unplug
virtio: console: Make read() return -ENODEV on hot-unplug
virtio: console: Unblock poll on port hot-unplug
virtio: console: Un-block reads on chardev close
virtio: console: Check if portdev is valid in send_control_msg()
virtio: console: Remove control vq data only if using multiport support
virtio: console: Reset vdev before removing device
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (22 commits)
ceph: do not carry i_lock for readdir from dcache
fs/ceph/xattr.c: Use kmemdup
rbd: passing wrong variable to bvec_kunmap_irq()
rbd: null vs ERR_PTR
ceph: fix num_pages_free accounting in pagelist
ceph: add CEPH_MDS_OP_SETDIRLAYOUT and associated ioctl.
ceph: don't crash when passed bad mount options
ceph: fix debugfs warnings
block: rbd: removing unnecessary test
block: rbd: fixed may leaks
ceph: switch from BKL to lock_flocks()
ceph: preallocate flock state without locks held
ceph: add pagelist_reserve, pagelist_truncate, pagelist_set_cursor
ceph: use mapping->nrpages to determine if mapping is empty
ceph: only invalidate on check_caps if we actually have pages
ceph: do not hide .snap in root directory
rbd: introduce rados block device (rbd), based on libceph
ceph: factor out libceph from Ceph file system
ceph-rbd: osdc support for osd call and rollback operations
ceph: messenger and osdc changes for rbd
...
Remove the BKL usage added in "block: push down BKL into .locked_ioctl".
Virtio-blk doesn't use the BKL for anything, and doesn't implement any
ioctl command by itself, but only uses the generic scsi_cmd_ioctl
which is fine without the BKL.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We should be passing "buf" here insead of "bv". This is tricky because
it's not the same as kmap() and kunmap(). GCC does warn about it if you
compile on i386 with CONFIG_HIGHMEM.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
Vivek Goyal