David Rientjes [Tue, 6 Jan 2009 22:39:01 +0000 (14:39 -0800)]
oom: print triggering task's cpuset and mems allowed
When cpusets are enabled, it's necessary to print the triggering task's
set of allowable nodes so the subsequently printed meminfo can be
interpreted correctly.
We also print the task's cpuset name for informational purposes.
[rientjes@google.com: task lock current before dereferencing cpuset] Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nick Piggin [Tue, 6 Jan 2009 22:38:59 +0000 (14:38 -0800)]
mm: invoke oom-killer from page fault
Rather than have the pagefault handler kill a process directly if it gets
a VM_FAULT_OOM, have it call into the OOM killer.
With increasingly sophisticated oom behaviour (cpusets, memory cgroups,
oom killing throttling, oom priority adjustment or selective disabling,
panic on oom, etc), it's silly to unconditionally kill the faulting
process at page fault time. Create a hook for pagefault oom path to call
into instead.
Only converted x86 and uml so far.
[akpm@linux-foundation.org: make __out_of_memory() static]
[akpm@linux-foundation.org: fix comment] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Jeff Dike <jdike@addtoit.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Brice Goglin [Tue, 6 Jan 2009 22:38:57 +0000 (14:38 -0800)]
mm: rework do_pages_move() to work on page_sized chunks
Rework do_pages_move() to work by page-sized chunks of struct page_to_node
that are passed to do_move_page_to_node_array(). We now only have to
allocate a single page instead a possibly very large vmalloc area to store
all page_to_node entries.
As a result, new_page_node() will now have a very small lookup, hidding
much of the overall sys_move_pages() overhead.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr> Signed-off-by: Nathalie Furmento <Nathalie.Furmento@labri.fr> Acked-by: Christoph Lameter <cl@linux-foundation.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Tue, 6 Jan 2009 22:38:57 +0000 (14:38 -0800)]
mm: don't mark_page_accessed in shmem_fault
Following "mm: don't mark_page_accessed in fault path", which now
places a mark_page_accessed() in zap_pte_range(), we should remove
the mark_page_accessed() from shmem_fault().
Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Johannes Weiner <hannes@saeurebad.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nick Piggin [Tue, 6 Jan 2009 22:38:55 +0000 (14:38 -0800)]
mm: don't mark_page_accessed in fault path
Doing a mark_page_accessed at fault-time, then doing SetPageReferenced at
unmap-time if the pte is young has a number of problems.
mark_page_accessed is supposed to be roughly the equivalent of a young pte
for unmapped references. Unfortunately it doesn't come with any context:
after being called, reclaim doesn't know who or why the page was touched.
So calling mark_page_accessed not only adds extra lru or PG_referenced
manipulations for pages that are already going to have pte_young ptes anyway,
but it also adds these references which are difficult to work with from the
context of vma specific references (eg. MADV_SEQUENTIAL pte_young may not
wish to contribute to the page being referenced).
Then, simply doing SetPageReferenced when zapping a pte and finding it is
young, is not a really good solution either. SetPageReferenced does not
correctly promote the page to the active list for example. So after removing
mark_page_accessed from the fault path, several mmap()+touch+munmap() would
have a very different result from several read(2) calls for example, which
is not really desirable.
Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Johannes Weiner <hannes@saeurebad.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mel Gorman [Tue, 6 Jan 2009 22:38:54 +0000 (14:38 -0800)]
mm: report the MMU pagesize in /proc/pid/smaps
The KernelPageSize entry in /proc/pid/smaps is the pagesize used by the
kernel to back a VMA. This matches the size used by the MMU in the
majority of cases. However, one counter-example occurs on PPC64 kernels
whereby a kernel using 64K as a base pagesize may still use 4K pages for
the MMU on older processor. To distinguish, this patch reports
MMUPageSize as the pagesize used by the MMU in /proc/pid/smaps.
Mel Gorman [Tue, 6 Jan 2009 22:38:53 +0000 (14:38 -0800)]
mm: report the pagesize backing a VMA in /proc/pid/smaps
It is useful to verify a hugepage-aware application is using the expected
pagesizes for its memory regions. This patch creates an entry called
KernelPageSize in /proc/pid/smaps that is the size of page used by the
kernel to back a VMA. The entry is not called PageSize as it is possible
the MMU uses a different size. This extension should not break any sensible
parser that skips lines containing unrecognised information.
Supply dm_add_exception as a callback to the read_metadata function.
Add a status function ready for a later patch and name the functions
consistently.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm snapshot: split out exception store implementations
Move the existing snapshot exception store implementations out into
separate files. Later patches will place these behind a new
interface in preparation for alternative implementations.
dm snapshot: separate out exception store interface
Pull structures that bridge the gap between snapshot and
exception store out of dm-snap.h and put them in a new
.h file - dm-exception-store.h. This file will define the
API for new exception stores.
Ultimately, dm-snap.h is unnecessary, since only dm-snap.c
should be using it.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The same workqueue is used both for sending uevents and processing queued I/O.
Deadlock has been reported in RHEL5 when sending a uevent was blocked waiting
for the queued I/O to be processed. Use scheduled_work() for the asynchronous
uevents instead.
Milan Broz [Tue, 6 Jan 2009 03:05:12 +0000 (03:05 +0000)]
dm: add name and uuid to sysfs
Implement simple read-only sysfs entry for device-mapper block device.
This patch adds a simple sysfs directory named "dm" under block device
properties and implements
- name attribute (string containing mapped device name)
- uuid attribute (string containing UUID, or empty string if not set)
The kobject is embedded in mapped_device struct, so no additional
memory allocation is needed for initializing sysfs entry.
During the processing of sysfs attribute we need to lock mapped device
which is done by a new function dm_get_from_kobj, which returns the md
associated with kobject and increases the usage count.
Each 'show attribute' function is responsible for its own locking.
Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mikulas Patocka [Tue, 6 Jan 2009 03:05:10 +0000 (03:05 +0000)]
dm table: rework reference counting
Rework table reference counting.
The existing code uses a reference counter. When the last reference is
dropped and the counter reaches zero, the table destructor is called.
Table reference counters are acquired/released from upcalls from other
kernel code (dm_any_congested, dm_merge_bvec, dm_unplug_all).
If the reference counter reaches zero in one of the upcalls, the table
destructor is called from almost random kernel code.
This leads to various problems:
* dm_any_congested being called under a spinlock, which calls the
destructor, which calls some sleeping function.
* the destructor attempting to take a lock that is already taken by the
same process.
* stale reference from some other kernel code keeps the table
constructed, which keeps some devices open, even after successful
return from "dmsetup remove". This can confuse lvm and prevent closing
of underlying devices or reusing device minor numbers.
The patch changes reference counting so that the table destructor can be
called only at predetermined places.
The table has always exactly one reference from either mapped_device->map
or hash_cell->new_map. After this patch, this reference is not counted
in table->holders. A pair of dm_create_table/dm_destroy_table functions
is used for table creation/destruction.
Temporary references from the other code increase table->holders. A pair
of dm_table_get/dm_table_put functions is used to manipulate it.
When the table is about to be destroyed, we wait for table->holders to
reach 0. Then, we call the table destructor. We use active waiting with
msleep(1), because the situation happens rarely (to one user in 5 years)
and removing the device isn't performance-critical task: the user doesn't
care if it takes one tick more or not.
This way, the destructor is called only at specific points
(dm_table_destroy function) and the above problems associated with lazy
destruction can't happen.
Finally remove the temporary protection added to dm_any_congested().
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Andi Kleen [Tue, 6 Jan 2009 03:05:09 +0000 (03:05 +0000)]
dm: support barriers on simple devices
Implement barrier support for single device DM devices
This patch implements barrier support in DM for the common case of dm linear
just remapping a single underlying device. In this case we can safely
pass the barrier through because there can be no reordering between
devices.
NB. Any DM device might cease to support barriers if it gets
reconfigured so code must continue to allow for a possible
-EOPNOTSUPP on every barrier bio submitted. - agk
Kiyoshi Ueda [Tue, 6 Jan 2009 03:05:07 +0000 (03:05 +0000)]
dm request: extend target interface
This patch adds the following target interfaces for request-based dm.
map_rq : for mapping a request
rq_end_io : for finishing a request
busy : for avoiding performance regression from bio-based dm.
Target can tell dm core not to map requests now, and
that may help requests in the block layer queue to be
bigger by I/O merging.
In bio-based dm, this behavior is done by device
drivers managing the block layer queue.
But in request-based dm, dm core has to do that
since dm core manages the block layer queue.
Takahiro Yasui [Tue, 6 Jan 2009 03:04:59 +0000 (03:04 +0000)]
dm log: avoid reinitialising io_req on every operation
rw_header function updates three members of io_req data every time
when I/O is processed. bi_rw and notify.fn are never modified once
they get initialized, and so they can be set in advance.
header_to_disk() can also be pulled out of write_header() since only one
caller needs it and write_header() can be replaced by rw_header()
directly.
Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Change dm_unregister_target to return void and use BUG() for error
reporting.
dm_unregister_target can only fail because of programming bug in the
target driver. It can't fail because of user's behavior or disk errors.
This patch changes unregister_target to return void and use BUG if
someone tries to unregister non-registered target or unregister target
that is in use.
This patch removes code duplication (testing of error codes in all dm
targets) and reports bugs in just one place, in dm_unregister_target. In
some target drivers, these return codes were ignored, which could lead
to a situation where bugs could be missed.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Always increase the error count when I/O on a leg of a mirror fails.
The error count is used to decide whether to select an alternative
mirror leg. If the target doesn't use the "handle_errors" feature, the
error count is not updated and the bio can get requeued forever by the
read callback.
Fix it by increasing error_count before the handle_errors feature
checking.
Cc: stable@kernel.org Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Takahiro Yasui [Tue, 6 Jan 2009 03:04:56 +0000 (03:04 +0000)]
dm log: fix dm_io_client leak on error paths
In create_log_context function, dm_io_client_destroy function needs
to be called, when memory allocation of disk_header, sync_bits and
recovering_bits failed, but dm_io_client_destroy is not called.
Cc: stable@kernel.org Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Acked-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mikulas Patocka [Tue, 6 Jan 2009 03:04:54 +0000 (03:04 +0000)]
dm snapshot: change yield to msleep
Change yield() to msleep(1). If the thread had realtime priority,
yield() doesn't really yield, so the yielding process would loop
indefinitely and cause machine lockup.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mikulas Patocka [Tue, 6 Jan 2009 03:04:53 +0000 (03:04 +0000)]
dm table: drop reference at unbind
Move one dm_table_put() so that the last reference in the thread
gets dropped in __unbind().
This is required for a following patch,
dm-table-rework-reference-counting.patch, which will change the logic in
such a way that table destructor is called only at specific points in
the code.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
module: convert to stop_machine_create/destroy.
stop_machine: introduce stop_machine_create/destroy.
parisc: fix module loading failure of large kernel modules
module: fix module loading failure of large kernel modules for parisc
module: fix warning of unused function when !CONFIG_PROC_FS
kernel/module.c: compare symbol values when marking symbols as exported in /proc/kallsyms.
remove CONFIG_KMOD
Linus Torvalds [Tue, 6 Jan 2009 03:03:11 +0000 (19:03 -0800)]
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
swiotlb: Don't include linux/swiotlb.h twice in lib/swiotlb.c
intel-iommu: fix build error with INTR_REMAP=y and DMAR=n
swiotlb: add missing __init annotations
Linus Torvalds [Tue, 6 Jan 2009 02:58:06 +0000 (18:58 -0800)]
Merge branch 'i2c-next' of git://aeryn.fluff.org.uk/bjdooks/linux
* 'i2c-next' of git://aeryn.fluff.org.uk/bjdooks/linux:
i2c-omap: fix type of irq handler function
i2c-s3c2410: Change IRQ to be plain integer.
i2c-s3c2410: Allow more than one i2c-s3c2410 adapter
i2c-s3c2410: Remove default platform data.
i2c-s3c2410: Use platform data for gpio configuration
i2c-s3c2410: Fixup style problems from checkpatch.pl
i2c-omap: Enable I2C wakeups for 34xx
i2c-omap: reprogram OCP_SYSCONFIG register after reset
i2c-omap: convert 'rev1' flag to generic 'rev' u8
i2c-omap: fix I2C timeouts due to recursive omap_i2c_{un,}idle()
i2c-omap: Clean-up i2c-omap
i2c-omap: Don't compile in OMAP15xx I2C ISR for non-OMAP15xx builds
i2c-omap: Mark init-only functions as __init
i2c-omap: Add support for omap34xx
i2c-omap: FIFO handling support and broken hw workaround for i2c-omap
i2c-omap: Add high-speed support to omap-i2c
i2c-omap: Close suspected race between omap_i2c_idle() and omap_i2c_isr()
i2c-omap: Do not use interruptible wait call in omap_i2c_xfer_msg
Fix up apparently-trivial conflict in drivers/i2c/busses/i2c-s3c2410.c
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw: (27 commits)
GFS2: Use DEFINE_SPINLOCK
GFS2: Fix use-after-free bug on umount (try #2)
Revert "GFS2: Fix use-after-free bug on umount"
GFS2: Streamline alloc calculations for writes
GFS2: Send useful information with uevent messages
GFS2: Fix use-after-free bug on umount
GFS2: Remove ancient, unused code
GFS2: Move four functions from super.c
GFS2: Fix bug in gfs2_lock_fs_check_clean()
GFS2: Send some sensible sysfs stuff
GFS2: Kill two daemons with one patch
GFS2: Move gfs2_recoverd into recovery.c
GFS2: Fix "truncate in progress" hang
GFS2: Clean up & move gfs2_quotad
GFS2: Add more detail to debugfs glock dumps
GFS2: Banish struct gfs2_rgrpd_host
GFS2: Move rg_free from gfs2_rgrpd_host to gfs2_rgrpd
GFS2: Move rg_igeneration into struct gfs2_rgrpd
GFS2: Banish struct gfs2_dinode_host
GFS2: Move i_size from gfs2_dinode_host and rename it to i_disksize
...
Linus Torvalds [Tue, 6 Jan 2009 02:47:12 +0000 (18:47 -0800)]
igb: fix anoying type mismatch warning on rx/tx queue sizing
When using "min()", the types of both sides should match. With the cpu
mask changes, the type of num_online_cpus() will now depend on config
options. Use "min_t()" with an explicit type instead.
And make the rx/tx case look the same too, just for sanity.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (44 commits)
qlge: Fix sparse warnings for tx ring indexes.
qlge: Fix sparse warning regarding rx buffer queues.
qlge: Fix sparse endian warning in ql_hw_csum_setup().
qlge: Fix sparse endian warning for inbound packet control block flags.
qlge: Fix sparse warnings for byte swapping in qlge_ethool.c
myri10ge: print MAC and serial number on probe failure
pkt_sched: cls_u32: Fix locking in u32_change()
iucv: fix cpu hotplug
af_iucv: Free iucv path/socket in path_pending callback
af_iucv: avoid left over IUCV connections from failing connects
af_iucv: New error return codes for connect()
net/ehea: bitops work on unsigned longs
Revert "net: Fix for initial link state in 2.6.28"
tcp: Kill extraneous SPLICE_F_NONBLOCK checks.
tcp: don't mask EOF and socket errors on nonblocking splice receive
dccp: Integrate the TFRC library with DCCP
dccp: Clean up ccid.c after integration of CCID plugins
dccp: Lockless integration of CCID congestion-control plugins
qeth: get rid of extra argument after printk to dev_* conversion
qeth: No large send using EDDP for HiperSockets.
...
Linus Torvalds [Tue, 6 Jan 2009 02:34:12 +0000 (18:34 -0800)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: ice1724 - Fix a typo in IEC958 PCM name
ASoC: fix davinci-sffsdr buglet
ALSA: sound/usb: Use negated usb_endpoint_xfer_control, etc
ALSA: hda - cxt5051 report jack state
ALSA: hda - add basic jack reporting functions to patch_conexant.c
ALSA: Use usb_set/get_intfdata
ASoC: Clean up kerneldoc warnings
ASoC: Fix pxa2xx-pcm checks for invalid DMA channels
LSA: hda - Add HP Acacia detection
ALSA: hda - fix name for ALC1200
ALSA: sound/usb: use USB API functions rather than constants
ASoC: TWL4030: DAPM based capture implementation
ASoC: TWL4030: Make the enum filter generic for twl4030
Linus Torvalds [Tue, 6 Jan 2009 02:33:38 +0000 (18:33 -0800)]
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] Fix on resume, now preserves user policy min/max.
[CPUFREQ] Add Celeron Core support to p4-clockmod.
[CPUFREQ] add to speedstep-lib additional fsb values for core processors
[CPUFREQ] Disable sysfs ui for p4-clockmod.
[CPUFREQ] p4-clockmod: reduce noise
[CPUFREQ] clean up speedstep-centrino and reduce cpumask_t usage
Linus Torvalds [Tue, 6 Jan 2009 02:32:43 +0000 (18:32 -0800)]
Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2: (138 commits)
ocfs2: Access the right buffer_head in ocfs2_merge_rec_left.
ocfs2: use min_t in ocfs2_quota_read()
ocfs2: remove unneeded lvb casts
ocfs2: Add xattr support checking in init_security
ocfs2: alloc xattr bucket in ocfs2_xattr_set_handle
ocfs2: calculate and reserve credits for xattr value in mknod
ocfs2/xattr: fix credits calculation during index create
ocfs2/xattr: Always updating ctime during xattr set.
ocfs2/xattr: Remove extend_trans call and add its credits from the beginning
ocfs2/dlm: Fix race during lockres mastery
ocfs2/dlm: Fix race in adding/removing lockres' to/from the tracking list
ocfs2/dlm: Hold off sending lockres drop ref message while lockres is migrating
ocfs2/dlm: Clean up errors in dlm_proxy_ast_handler()
ocfs2/dlm: Fix a race between migrate request and exit domain
ocfs2: One more hamming code optimization.
ocfs2: Another hamming code optimization.
ocfs2: Don't hand-code xor in ocfs2_hamming_encode().
ocfs2: Enable metadata checksums.
ocfs2: Validate superblock with checksum and ecc.
ocfs2: Checksum and ECC for directory blocks.
...
Linus Torvalds [Tue, 6 Jan 2009 02:32:06 +0000 (18:32 -0800)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
inotify: fix type errors in interfaces
fix breakage in reiserfs_new_inode()
fix the treatment of jfs special inodes
vfs: remove duplicate code in get_fs_type()
add a vfs_fsync helper
sys_execve and sys_uselib do not call into fsnotify
zero i_uid/i_gid on inode allocation
inode->i_op is never NULL
ntfs: don't NULL i_op
isofs check for NULL ->i_op in root directory is dead code
affs: do not zero ->i_op
kill suid bit only for regular files
vfs: lseek(fd, 0, SEEK_CUR) race condition
Nick Piggin [Tue, 6 Jan 2009 02:05:50 +0000 (03:05 +0100)]
mm lockless pagecache barrier fix
An XFS workload showed up a bug in the lockless pagecache patch. Basically it
would go into an "infinite" loop, although it would sometimes be able to break
out of the loop! The reason is a missing compiler barrier in the "increment
reference count unless it was zero" case of the lockless pagecache protocol in
the gang lookup functions.
This would cause the compiler to use a cached value of struct page pointer to
retry the operation with, rather than reload it. So the page might have been
removed from pagecache and freed (refcount==0) but the lookup would not correctly
notice the page is no longer in pagecache, and keep attempting to increment the
refcount and failing, until the page gets reallocated for something else. This
isn't a data corruption because the condition will be detected if the page has
been reallocated. However it can result in a lockup.
Linus points out that ACCESS_ONCE is also required in that pointer load, even
if it's absence is not causing a bug on our particular build. The most general
way to solve this is just to put an rcu_dereference in radix_tree_deref_slot.
Assembly of find_get_pages,
before:
.L220:
movq (%rbx), %rax #* ivtmp.1162, tmp82
movq (%rax), %rdi #, prephitmp.1149
.L218:
testb $1, %dil #, prephitmp.1149
jne .L217 #,
testq %rdi, %rdi # prephitmp.1149
je .L203 #,
cmpq $-1, %rdi #, prephitmp.1149
je .L217 #,
movl 8(%rdi), %esi # <variable>._count.counter, c
testl %esi, %esi # c
je .L218 #,
after:
.L212:
movq (%rbx), %rax #* ivtmp.1109, tmp81
movq (%rax), %rdi #, ret
testb $1, %dil #, ret
jne .L211 #,
testq %rdi, %rdi # ret
je .L197 #,
cmpq $-1, %rdi #, ret
je .L211 #,
movl 8(%rdi), %esi # <variable>._count.counter, c
testl %esi, %esi # c
je .L212 #,
(notice the obvious infinite loop in the first example, if page->count remains 0)
Signed-off-by: Nick Piggin <npiggin@suse.de> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ron Mercer [Tue, 6 Jan 2009 02:19:59 +0000 (18:19 -0800)]
qlge: Fix sparse warnings for tx ring indexes.
Warnings:
drivers/net/qlge/qlge_main.c:1474:34: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1475:36: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1592:51: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1941:20: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1941:20: expected restricted unsigned int [usertype] tid
drivers/net/qlge/qlge_main.c:1941:20: got int [signed] index
drivers/net/qlge/qlge_main.c:1945:24: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1945:24: expected restricted unsigned int [usertype] txq_idx
drivers/net/qlge/qlge_main.c:1945:24: got unsigned int [unsigned] [usertype] tx_ring_idx
Signed-off-by: Ron Mercer <ron.mercer@qlogic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Warnings:
drivers/net/qlge/qlge_main.c:909:17: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:909:17: expected unsigned int [unsigned] [usertype] addr_lo
drivers/net/qlge/qlge_main.c:909:17: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:911:17: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:911:17: expected unsigned int [unsigned] [usertype] addr_hi
drivers/net/qlge/qlge_main.c:911:17: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:974:17: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:974:17: expected unsigned int [unsigned] [usertype] addr_lo
drivers/net/qlge/qlge_main.c:974:17: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:975:17: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:975:17: expected unsigned int [unsigned] [usertype] addr_hi
drivers/net/qlge/qlge_main.c:975:17: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:2132:16: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:2132:16: expected unsigned int [unsigned] [usertype] addr_lo
drivers/net/qlge/qlge_main.c:2132:16: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:2133:16: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:2133:16: expected unsigned int [unsigned] [usertype] addr_hi
drivers/net/qlge/qlge_main.c:2133:16: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:2212:15: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:2212:15: expected unsigned int [unsigned] [usertype] addr_lo
drivers/net/qlge/qlge_main.c:2212:15: got restricted unsigned int [usertype] <noident>
drivers/net/qlge/qlge_main.c:2214:15: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:2214:15: expected unsigned int [unsigned] [usertype] addr_hi
drivers/net/qlge/qlge_main.c:2214:15: got restricted unsigned int [usertype] <noident>
Signed-off-by: Ron Mercer <ron.mercer@qlogic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Ron Mercer [Tue, 6 Jan 2009 02:18:45 +0000 (18:18 -0800)]
qlge: Fix sparse endian warning in ql_hw_csum_setup().
Changed u16 to __sum16 usage.
Warnings:
drivers/net/qlge/qlge_main.c:1897:9: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1897:9: expected unsigned short [usertype] *check
drivers/net/qlge/qlge_main.c:1897:9: got restricted unsigned short *<noident>
drivers/net/qlge/qlge_main.c:1903:9: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1903:9: expected unsigned short [usertype] *check
drivers/net/qlge/qlge_main.c:1903:9: got restricted unsigned short *<noident>
drivers/net/qlge/qlge_main.c:1909:9: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_main.c:1909:9: expected unsigned short [unsigned] [short] [usertype] <noident>
Signed-off-by: Ron Mercer <ron.mercer@qlogic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Ron Mercer [Tue, 6 Jan 2009 02:18:22 +0000 (18:18 -0800)]
qlge: Fix sparse endian warning for inbound packet control block flags.
Changed flags element from __le32 to 3 reserved bytes and one byte of
flags. Changed flags bit definitions to reflect byte width instead of
__le32 width.
Warnings:
drivers/net/qlge/qlge_main.c:1206:16: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1207:16: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1233:17: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1276:17: warning: restricted degrades to integer
drivers/net/qlge/qlge_main.c:1349:19: warning: restricted degrades to integer
Signed-off-by: Ron Mercer <ron.mercer@qlogic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Ron Mercer [Tue, 6 Jan 2009 02:17:33 +0000 (18:17 -0800)]
qlge: Fix sparse warnings for byte swapping in qlge_ethool.c
drivers/net/qlge/qlge_ethtool.c:59:23: warning: cast to restricted type
drivers/net/qlge/qlge_ethtool.c:59:21: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_ethtool.c:59:21: expected restricted unsigned short [usertype] irq_delay
drivers/net/qlge/qlge_ethtool.c:59:21: got unsigned short [unsigned] [usertype] <noident>
drivers/net/qlge/qlge_ethtool.c:61:8: warning: cast to restricted type
drivers/net/qlge/qlge_ethtool.c:60:21: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_ethtool.c:60:21: expected restricted unsigned short [usertype] pkt_delay
drivers/net/qlge/qlge_ethtool.c:60:21: got unsigned short [unsigned] [usertype] <noident>
drivers/net/qlge/qlge_ethtool.c:82:23: warning: cast to restricted type
drivers/net/qlge/qlge_ethtool.c:82:21: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_ethtool.c:82:21: expected restricted unsigned short [usertype] irq_delay
drivers/net/qlge/qlge_ethtool.c:82:21: got unsigned short [unsigned] [usertype] <noident>
drivers/net/qlge/qlge_ethtool.c:84:8: warning: cast to restricted type
drivers/net/qlge/qlge_ethtool.c:83:21: warning: incorrect type in assignment (different base types)
drivers/net/qlge/qlge_ethtool.c:83:21: expected restricted unsigned short [usertype] pkt_delay
drivers/net/qlge/qlge_ethtool.c:83:21: got unsigned short [unsigned] [usertype] <noident>
Signed-off-by: Ron Mercer <ron.mercer@qlogic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Jarek Poplawski [Tue, 6 Jan 2009 02:14:19 +0000 (18:14 -0800)]
pkt_sched: cls_u32: Fix locking in u32_change()
New nodes are inserted in u32_change() under rtnl_lock() with wmb(),
so without tcf_tree_lock() like in other classifiers (e.g. cls_fw).
This isn't enough without rmb() on the read side, but on the other
hand adding such barriers doesn't give any savings, so the lock is
added instead.
Reported-by: m0sia <m0sia@plotinka.ru> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Julian Calaby [Tue, 6 Jan 2009 02:13:49 +0000 (18:13 -0800)]
sparc: Fix minor SPARC32 compile error
When CONFIG_PROC_FS is unset, include/linux/interrupt.h defines
init_irq_proc() as an empty function.
arch/sparc/kernel/irq_32.c defines this function unconditionally.
Fix the latter so that it only defines this function when CONFIG_PROC_FS
is set.
This fixes the following error:
arch/sparc/kernel/irq_32.c:672: error: redefinition of 'init_irq_proc'
include/linux/interrupt.h:461: error: previous definition of
'init_irq_proc' was here
This was found using randconfig builds.
Signed-off-by: Julian Calaby <julian.calaby@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Heiko Carstens [Tue, 6 Jan 2009 02:09:02 +0000 (18:09 -0800)]
iucv: fix cpu hotplug
If the iucv module is compiled in/loaded but no user is registered cpu
hot remove doesn't work. Reason for that is that the iucv cpu hotplug
notifier on CPU_DOWN_PREPARE checks if the iucv_buffer_cpumask would
be empty after the corresponding bit would be cleared. However the bit
was never set since iucv wasn't enable. That causes all cpu hot unplug
operations to fail in this scenario.
To fix this use iucv_path_table as an indicator wether iucv is enabled
or not.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
af_iucv: Free iucv path/socket in path_pending callback
Free iucv path after iucv_path_sever() calls in iucv_callback_connreq()
(path_pending() iucv callback).
If iucv_path_accept() fails, free path and free/kill newly created socket.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
If the iucv_path_connect() call fails then return an error code that
corresponds to the iucv_path_connect() failure condition; instead of
returning -ECONNREFUSED for any failure.
This helps to improve error handling for user space applications
(e.g. inform the user that the z/VM guest is not authorized to
connect to other guest virtual machines).
The error return codes are based on those described in connect(2).
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
... if you revert a commit, revert the fixups elsewhere that had been
triggered by it. Such as 8c56250f48347750c82ab18d98d647dcf99ca674
(lockdep, UML: fix compilation when CONFIG_TRACE_IRQFLAGS_SUPPORT is not set).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Al Viro [Mon, 5 Jan 2009 17:18:42 +0000 (17:18 +0000)]
get rid of the last symlink in uml build
We need to make asm-offsets.h contents visible for objects built
with userland headers. Instead of creating a symlink, just have the
file with equivalent include (relative to location of header) created
once. That kills the last symlink used in arch/um builds.
Additionally, both generated headers can become dependencies of
archprepare now, killing the misuse of prepare.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The flags field of struct ehea_port is only used with test_bit(),
clear_bit() and set_bit() and these interfaces only work on
"unsigned long"s, so change the field to be an "unsigned long". Also,
this field only has two bits defined for it (0 and 1) so will still be
fine if someone builds this driver for a 32 bit arch (at least as far as
this flags field is concerned).
Also note that ehea_driver_flags is only used in ehca_main.c, so make it
static in there.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
We can't fix this issue in this way, because we now can try
to take the dev_base_lock rwlock as a writer in software interrupt
context and that is not allowed without major surgery elsewhere.
This initial link state problem needs to be solved in some other
way.
Signed-off-by: David S. Miller <davem@davemloft.net>
Michael Kerrisk [Mon, 5 Jan 2009 12:19:16 +0000 (07:19 -0500)]
inotify: fix type errors in interfaces
The problems lie in the types used for some inotify interfaces, both at the kernel level and at the glibc level. This mail addresses the kernel problem. I will follow up with some suggestions for glibc changes.
For the sys_inotify_rm_watch() interface, the type of the 'wd' argument is
currently 'u32', it should be '__s32' . That is Robert's suggestion, and
is consistent with the other declarations of watch descriptors in the
kernel source, in particular, the inotify_event structure in
include/linux/inotify.h:
struct inotify_event {
__s32 wd; /* watch descriptor */
__u32 mask; /* watch mask */
__u32 cookie; /* cookie to synchronize two events */
__u32 len; /* length (including nulls) of name */
char name[0]; /* stub for possible name */
};
The patch makes the changes needed for inotify_rm_watch().
Signed-off-by: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Robert Love <rlove@google.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fsync currently has a fdatawrite/fdatawait pair around the method call,
and a mutex_lock/unlock of the inode mutex. All callers of fsync have
to duplicate this, but we have a few and most of them don't quite get
it right. This patch adds a new vfs_fsync that takes care of this.
It's a little more complicated as usual as ->fsync might get a NULL file
pointer and just a dentry from nfsd, but otherwise gets afile and we
want to take the mapping and file operations from it when it is there.
Notes on the fsync callers:
- ecryptfs wasn't calling filemap_fdatawrite / filemap_fdatawait on the
lower file
- coda wasn't calling filemap_fdatawrite / filemap_fdatawait on the host
file, and returning 0 when ->fsync was missing
- shm wasn't calling either filemap_fdatawrite / filemap_fdatawait nor
taking i_mutex. Now given that shared memory doesn't have disk
backing not doing anything in fsync seems fine and I left it out of
the vfs_fsync conversion for now, but in that case we might just
not pass it through to the lower file at all but just call the no-op
simple_sync_file directly.
[and now actually export vfs_fsync]
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Eric Paris [Wed, 17 Dec 2008 18:53:20 +0000 (13:53 -0500)]
sys_execve and sys_uselib do not call into fsnotify
sys_execve and sys_uselib do not call into fsnotify so inotify does not get
open events for these types of syscalls. This patch simply makes the
requisite fsnotify calls.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Thu, 4 Dec 2008 15:06:33 +0000 (10:06 -0500)]
inode->i_op is never NULL
We used to have rather schizophrenic set of checks for NULL ->i_op even
though it had been eliminated years ago. You'd need to go out of your
way to set it to NULL explicitly _and_ a bunch of code would die on
such inodes anyway. After killing two remaining places that still
did that bogosity, all that crap can go away.
Al Viro [Thu, 4 Dec 2008 14:57:25 +0000 (09:57 -0500)]
isofs check for NULL ->i_op in root directory is dead code
for one thing it never happens, for another we check that inode
is a directory right after that place anyway (and we'd already
checked that reading it from disk has not failed).
Dmitri Monakhov [Mon, 1 Dec 2008 22:34:56 +0000 (14:34 -0800)]
kill suid bit only for regular files
We don't have to do it because it is useless for non regular files.
In fact block device may trigger this path without dentry->d_inode->i_mutex.
(akpm: concerns were expressed (by me) about S_ISDIR inodes)
Signed-off-by: Dmitri Monakhov <dmonakhov@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Alain Knaff [Tue, 11 Nov 2008 01:08:08 +0000 (17:08 -0800)]
vfs: lseek(fd, 0, SEEK_CUR) race condition
This patch fixes a race condition in lseek. While it is expected that
unpredictable behaviour may result while repositioning the offset of a
file descriptor concurrently with reading/writing to the same file
descriptor, this should not happen when merely *reading* the file
descriptor's offset.
Unfortunately, the only portable way in Unix to read a file
descriptor's offset is lseek(fd, 0, SEEK_CUR); however executing this
concurrently with read/write may mess up the position.
[with fixes from akpm]
Signed-off-by: Alain Knaff <alain@knaff.lu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tiger Yang [Tue, 9 Dec 2008 08:42:51 +0000 (16:42 +0800)]
ocfs2: calculate and reserve credits for xattr value in mknod
We extend the credits for xattr's large value in set_value_outside
before, this can give rise to a credits issue when we set one security
entry and two acl entries duing mknod. As we remove extend_trans form
set_value_outside, we must calculate and reserve the credits for
xattr's large value in mknod.
Signed-off-by: Tiger Yang <tiger.yang@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Tao Ma [Thu, 4 Dec 2008 22:20:56 +0000 (06:20 +0800)]
ocfs2/xattr: fix credits calculation during index create
When creating a xattr index block, the old calculation forget
to add credits for the meta change of the alloc file. So add
more credits and more comments to explain it.
Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Tao Ma [Thu, 4 Dec 2008 22:20:55 +0000 (06:20 +0800)]
ocfs2/xattr: Always updating ctime during xattr set.
In xattr set, we should always update ctime if the operation goes
sucessfully. The old one mistakenly put it in ocfs2_xattr_set_entry
which is only called when we set xattr in inode or xattr block. The
side benefit is that it resolve the bug 1052 since in that scenario,
ocfs2_calc_xattr_set_need only calc out the xattr set credits while
ocfs2_xattr_set_entry update the inode also which isn't concerned with
the process of xattr set.
Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Tao Ma [Thu, 4 Dec 2008 22:20:54 +0000 (06:20 +0800)]
ocfs2/xattr: Remove extend_trans call and add its credits from the beginning
Actually, when setting a new xattr value, we know it from the very
beginning, and it isn't like the extension of bucket in which case
we can't figure it out. So remove ocfs2_extend_trans in that function
and calculate it before the transaction. It also relieve acl operation
from the worry about the side effect of ocfs2_extend_trans.
Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Sunil Mushran [Tue, 16 Dec 2008 23:49:23 +0000 (15:49 -0800)]
ocfs2/dlm: Fix race during lockres mastery
dlm_get_lock_resource() is supposed to return a lock resource with a proper
master. If multiple concurrent threads attempt to lookup the lockres for the
same lockid while the lock mastery in underway, one or more threads are likely
to return a lockres without a proper master.
This patch makes the threads wait in dlm_get_lock_resource() while the mastery
is underway, ensuring all threads return the lockres with a proper master.
This issue is known to be limited to users using the flock() syscall. For all
other fs operations, the ocfs2 dlmglue layer serializes the dlm op for each
lockid.
Users encountering this bug will see flock() return EINVAL and dmesg have the
following error:
ERROR: Dlm error "DLM_BADARGS" while calling dlmlock on resource <LOCKID>: bad api args
Reported-by: Coly Li <coyli@suse.de> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Sunil Mushran [Tue, 16 Dec 2008 23:49:22 +0000 (15:49 -0800)]
ocfs2/dlm: Fix race in adding/removing lockres' to/from the tracking list
This patch adds a new lock, dlm->tracking_lock, to protect adding/removing
lockres' to/from the dlm->tracking_list. We were previously using dlm->spinlock
for the same, but that proved inadequate as we could be freeing a lockres from
a context that did not hold that lock. As the new lock only protects this list,
we can explicitly take it when removing the lockres from the tracking list.
This bug was exposed when testing multiple processes concurrently flock() the
same file.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Sunil Mushran [Tue, 16 Dec 2008 23:49:20 +0000 (15:49 -0800)]
ocfs2/dlm: Clean up errors in dlm_proxy_ast_handler()
Patch cleans printed errors in dlm_proxy_ast_handler(). The errors now includes
the node number that sent the (b)ast. Also it reduces the number of endian swaps
of the cookie.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Sunil Mushran [Tue, 16 Dec 2008 23:49:19 +0000 (15:49 -0800)]
ocfs2/dlm: Fix a race between migrate request and exit domain
Patch address a racing migrate request message and an exit domain message.
Instead of blocking exit domains for the duration of the migrate, we ignore
failure to deliver that message. This is because an exiting domain should
not have any active locks and thus has no role to play in the migration.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Joel Becker [Tue, 16 Dec 2008 21:54:40 +0000 (13:54 -0800)]
ocfs2: One more hamming code optimization.
The previous optimization used a fast find-highest-bit-set operation to
give us a good starting point in calc_code_bit(). This version lets the
caller cache the previous code buffer bit offset. Thus, the next call
always starts where the last one left off.
This reduces the calculation another 39%, for a total 80% reduction from
the original, naive implementation. At least, on my machine. This also
brings the parity calculation to within an order of magnitude of the
crc32 calculation.
Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Joel Becker [Tue, 16 Dec 2008 02:24:33 +0000 (18:24 -0800)]
ocfs2: Another hamming code optimization.
In the calc_code_bit() function, we must find all powers of two beneath
the code bit number, *after* it's shifted by those powers of two. This
requires a loop to see where it ends up.
We can optimize it by starting at its most significant bit. This shaves
32% off the time, for a total of 67.6% shaved off of the original, naive
implementation.
Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Joel Becker [Tue, 16 Dec 2008 01:13:48 +0000 (17:13 -0800)]
ocfs2: Don't hand-code xor in ocfs2_hamming_encode().
When I wrote ocfs2_hamming_encode(), I was following documentation of
the algorithm and didn't have quite the (possibly still imperfect) grasp
of it I do now. As part of this, I literally hand-coded xor. I would
test a bit, and then add that bit via xor to the parity word.
I can, of course, just do a single xor of the parity word and the source
word (the code buffer bit offset). This cuts CPU usage by 53% on a
mostly populated buffer (an inode containing utmp.h inline).
Joel
Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Code Review / linux-2.6.git / log