We have to delay vfs_dq_claim_space() until allocation context destruction.
Currently we have following call-trace:
ext4_mb_new_blocks()
  /* task is already holding ac->alloc_semp */
 ->ext4_mb_mark_diskspace_used
    ->vfs_dq_claim_space()  /*  acquire dqptr_sem here. Possible deadlock */
 ->ext4_mb_release_context() /* drop ac->alloc_semp here */

Let's move quota claiming to ext4_da_update_reserve_space()

 =======================================================
 [ INFO: possible circular locking dependency detected ]
 2.6.32-rc7 #18
 -------------------------------------------------------
 write-truncate-/3465 is trying to acquire lock:
  (&s->s_dquot.dqptr_sem){++++..}, at: [<c025e73b>] dquot_claim_space+0x3b/0x1b0

 but task is already holding lock:
  (&meta_group_info[i]->alloc_sem){++++..}, at: [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #3 (&meta_group_info[i]->alloc_sem){++++..}:
        [<c017d04b>] __lock_acquire+0xd7b/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0527191>] down_read+0x51/0x90
        [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370
        [<c02d0c1c>] ext4_mb_free_blocks+0x46c/0x870
        [<c029c9d3>] ext4_free_blocks+0x73/0x130
        [<c02c8cfc>] ext4_ext_truncate+0x76c/0x8d0
        [<c02a8087>] ext4_truncate+0x187/0x5e0
        [<c01e0f7b>] vmtruncate+0x6b/0x70
        [<c022ec02>] inode_setattr+0x62/0x190
        [<c02a2d7a>] ext4_setattr+0x25a/0x370
        [<c022ee81>] notify_change+0x151/0x340
        [<c021349d>] do_truncate+0x6d/0xa0
        [<c0221034>] may_open+0x1d4/0x200
        [<c022412b>] do_filp_open+0x1eb/0x910
        [<c021244d>] do_sys_open+0x6d/0x140
        [<c021258e>] sys_open+0x2e/0x40
        [<c0103100>] sysenter_do_call+0x12/0x32

 -> #2 (&ei->i_data_sem){++++..}:
        [<c017d04b>] __lock_acquire+0xd7b/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0527191>] down_read+0x51/0x90
        [<c02a5787>] ext4_get_blocks+0x47/0x450
        [<c02a74c1>] ext4_getblk+0x61/0x1d0
        [<c02a7a7f>] ext4_bread+0x1f/0xa0
        [<c02bcddc>] ext4_quota_write+0x12c/0x310
        [<c0262d23>] qtree_write_dquot+0x93/0x120
        [<c0261708>] v2_write_dquot+0x28/0x30
        [<c025d3fb>] dquot_commit+0xab/0xf0
        [<c02be977>] ext4_write_dquot+0x77/0x90
        [<c02be9bf>] ext4_mark_dquot_dirty+0x2f/0x50
        [<c025e321>] dquot_alloc_inode+0x101/0x180
        [<c029fec2>] ext4_new_inode+0x602/0xf00
        [<c02ad789>] ext4_create+0x89/0x150
        [<c0221ff2>] vfs_create+0xa2/0xc0
        [<c02246e7>] do_filp_open+0x7a7/0x910
        [<c021244d>] do_sys_open+0x6d/0x140
        [<c021258e>] sys_open+0x2e/0x40
        [<c0103100>] sysenter_do_call+0x12/0x32

 -> #1 (&sb->s_type->i_mutex_key#7/4){+.+...}:
        [<c017d04b>] __lock_acquire+0xd7b/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0526505>] mutex_lock_nested+0x65/0x2d0
        [<c0260c9d>] vfs_load_quota_inode+0x4bd/0x5a0
        [<c02610af>] vfs_quota_on_path+0x5f/0x70
        [<c02bc812>] ext4_quota_on+0x112/0x190
        [<c026345a>] sys_quotactl+0x44a/0x8a0
        [<c0103100>] sysenter_do_call+0x12/0x32

 -> #0 (&s->s_dquot.dqptr_sem){++++..}:
        [<c017d361>] __lock_acquire+0x1091/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0527191>] down_read+0x51/0x90
        [<c025e73b>] dquot_claim_space+0x3b/0x1b0
        [<c02cb95f>] ext4_mb_mark_diskspace_used+0x36f/0x380
        [<c02d210a>] ext4_mb_new_blocks+0x34a/0x530
        [<c02c83fb>] ext4_ext_get_blocks+0x122b/0x13c0
        [<c02a5966>] ext4_get_blocks+0x226/0x450
        [<c02a5ff3>] mpage_da_map_blocks+0xc3/0xaa0
        [<c02a6ed6>] ext4_da_writepages+0x506/0x790
        [<c01de272>] do_writepages+0x22/0x50
        [<c01d766d>] __filemap_fdatawrite_range+0x6d/0x80
        [<c01d7b9b>] filemap_flush+0x2b/0x30
        [<c02a40ac>] ext4_alloc_da_blocks+0x5c/0x60
        [<c029e595>] ext4_release_file+0x75/0xb0
        [<c0216b59>] __fput+0xf9/0x210
        [<c0216c97>] fput+0x27/0x30
        [<c02122dc>] filp_close+0x4c/0x80
        [<c014510e>] put_files_struct+0x6e/0xd0
        [<c01451b7>] exit_files+0x47/0x60
        [<c0146a24>] do_exit+0x144/0x710
        [<c0147028>] do_group_exit+0x38/0xa0
        [<c0159abc>] get_signal_to_deliver+0x2ac/0x410
        [<c0102849>] do_notify_resume+0xb9/0x890
        [<c01032d2>] work_notifysig+0x13/0x21

 other info that might help us debug this:

 3 locks held by write-truncate-/3465:
  #0:  (jbd2_handle){+.+...}, at: [<c02e1f8f>] start_this_handle+0x38f/0x5c0
  #1:  (&ei->i_data_sem){++++..}, at: [<c02a57f6>] ext4_get_blocks+0xb6/0x450
  #2:  (&meta_group_info[i]->alloc_sem){++++..}, at: [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370

 stack backtrace:
 Pid: 3465, comm: write-truncate- Not tainted 2.6.32-rc7 #18
 Call Trace:
  [<c0524cb3>] ? printk+0x1d/0x22
  [<c017ac9a>] print_circular_bug+0xca/0xd0
  [<c017d361>] __lock_acquire+0x1091/0x1260
  [<c016bca2>] ? sched_clock_local+0xd2/0x170
  [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0
  [<c017d5ea>] lock_acquire+0xba/0xd0
  [<c025e73b>] ? dquot_claim_space+0x3b/0x1b0
  [<c0527191>] down_read+0x51/0x90
  [<c025e73b>] ? dquot_claim_space+0x3b/0x1b0
  [<c025e73b>] dquot_claim_space+0x3b/0x1b0
  [<c02cb95f>] ext4_mb_mark_diskspace_used+0x36f/0x380
  [<c02d210a>] ext4_mb_new_blocks+0x34a/0x530
  [<c02c601d>] ? ext4_ext_find_extent+0x25d/0x280
  [<c02c83fb>] ext4_ext_get_blocks+0x122b/0x13c0
  [<c016bca2>] ? sched_clock_local+0xd2/0x170
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c016beef>] ? cpu_clock+0x4f/0x60
  [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0
  [<c052712c>] ? down_write+0x8c/0xa0
  [<c02a5966>] ext4_get_blocks+0x226/0x450
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c016beef>] ? cpu_clock+0x4f/0x60
  [<c017908b>] ? trace_hardirqs_off+0xb/0x10
  [<c02a5ff3>] mpage_da_map_blocks+0xc3/0xaa0
  [<c01d69cc>] ? find_get_pages_tag+0x16c/0x180
  [<c01d6860>] ? find_get_pages_tag+0x0/0x180
  [<c02a73bd>] ? __mpage_da_writepage+0x16d/0x1a0
  [<c01dfc4e>] ? pagevec_lookup_tag+0x2e/0x40
  [<c01ddf1b>] ? write_cache_pages+0xdb/0x3d0
  [<c02a7250>] ? __mpage_da_writepage+0x0/0x1a0
  [<c02a6ed6>] ext4_da_writepages+0x506/0x790
  [<c016beef>] ? cpu_clock+0x4f/0x60
  [<c016bca2>] ? sched_clock_local+0xd2/0x170
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c02a69d0>] ? ext4_da_writepages+0x0/0x790
  [<c01de272>] do_writepages+0x22/0x50
  [<c01d766d>] __filemap_fdatawrite_range+0x6d/0x80
  [<c01d7b9b>] filemap_flush+0x2b/0x30
  [<c02a40ac>] ext4_alloc_da_blocks+0x5c/0x60
  [<c029e595>] ext4_release_file+0x75/0xb0
  [<c0216b59>] __fput+0xf9/0x210
  [<c0216c97>] fput+0x27/0x30
  [<c02122dc>] filp_close+0x4c/0x80
  [<c014510e>] put_files_struct+0x6e/0xd0
  [<c01451b7>] exit_files+0x47/0x60
  [<c0146a24>] do_exit+0x144/0x710
  [<c017b163>] ? lock_release_holdtime+0x33/0x210
  [<c0528137>] ? _spin_unlock_irq+0x27/0x30
  [<c0147028>] do_group_exit+0x38/0xa0
  [<c017babb>] ? trace_hardirqs_on+0xb/0x10
  [<c0159abc>] get_signal_to_deliver+0x2ac/0x410
  [<c0102849>] do_notify_resume+0xb9/0x890
  [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0
  [<c017b163>] ? lock_release_holdtime+0x33/0x210
  [<c0165b50>] ? autoremove_wake_function+0x0/0x50
  [<c017ba54>] ? trace_hardirqs_on_caller+0x134/0x190
  [<c017babb>] ? trace_hardirqs_on+0xb/0x10
  [<c0300ba4>] ? security_file_permission+0x14/0x20
  [<c0215761>] ? vfs_write+0x131/0x190
  [<c0214f50>] ? do_sync_write+0x0/0x120
  [<c0103115>] ? sysenter_do_call+0x27/0x32
  [<c01032d2>] work_notifysig+0x13/0x21

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

Fix warnings:
fs/quota/quota_v2.c: In function ‘v2_read_file_info’:
fs/quota/quota_v2.c:123: warning: integer constant is too large for ‘long’ type
fs/quota/quota_v2.c:124: warning: integer constant is too large for ‘long’ type
Reported-by: NJerry Leo <jerryleo860202@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

Use a separate lock to protect s_groups_count and the other block
group descriptors which get changed via an on-line resize operation,
so we can stop overloading the use of lock_super().

Port of ext4 commit 32ed5058 by
Theodore Ts'o <tytso@mit.edu>.

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NJan Kara <jack@suse.cz>

Use a separate lock to protect the orphan list, so we can stop
overloading the use of lock_super().

Port of ext4 commit 3b9d4ed2
by Theodore Ts'o <tytso@mit.edu>.

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NJan Kara <jack@suse.cz>

The function ext3_mark_recovery_complete() is called from two call
paths: either (a) while mounting the filesystem, in which case there's
no danger of any other CPU calling write_super() until the mount is
completed, and (b) while remounting the filesystem read-write, in
which case the fs core has already locked the superblock.  This also
allows us to take out a very vile unlock_super()/lock_super() pair in
ext3_remount().

Port of ext4 commit a63c9eb2 by
Theodore Ts'o <tytso@mit.edu>.

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NJan Kara <jack@suse.cz>

ext3_fill_super() is no longer called by read_super(), and it is no
longer called with the superblock locked.  The
unlock_super()/lock_super() is no longer present, so this comment is
entirely superfluous.

Port of ext4 commit 32ed5058 by
Theodore Ts'o <tytso@mit.edu>.

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NJan Kara <jack@suse.cz>

- for(..) { mark_dquot_dirty(); } -> mark_all_dquot_dirty()
- for(..) { dput(); }             -> dqput_all()
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

This patch also fixes write vs chown race condition.
Acked-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently inode_reservation is managed by fs itself and this
reservation is transfered on dquot_transfer(). This means what
inode_reservation must always be in sync with
dquot->dq_dqb.dqb_rsvspace. Otherwise dquot_transfer() will result
in incorrect quota(WARN_ON in dquot_claim_reserved_space() will be
triggered)
This is not easy because of complex locking order issues
for example http://bugzilla.kernel.org/show_bug.cgi?id=14739

The patch introduce quota reservation field for each fs-inode
(fs specific inode is used in order to prevent bloating generic
vfs inode). This reservation is managed by quota code internally
similar to i_blocks/i_bytes and may not be always in sync with
internal fs reservation.

Also perform some code rearrangement:
- Unify dquot_reserve_space() and dquot_reserve_space()
- Unify dquot_release_reserved_space() and dquot_free_space()
- Also this patch add missing warning update to release_rsv()
  dquot_release_reserved_space() must call flush_warnings() as
  dquot_free_space() does.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

Quota code requires unlocked version of this function. Off course
we can just copy-paste the code, but copy-pasting is always an evil.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently all quota block reservation macros contains hardcoded "2"
aka MAXQUOTAS value. This is no good because in some places it is not
obvious to understand what does this digit represent. Let's introduce
new macro with self descriptive name.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  pata_bf54x: handle portmuxing of pins through GPIO PORTs

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM: Runtime PM documentation update
  PM / Runtime: Use device type and device class callbacks
  PM: Use pm_runtime_put_sync in system resume
  PM: Measure device suspend and resume times
  PM: Make the initcall_debug style timing for suspend/resume complete

* git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  jfs: Fix 32bit build warning
  Remove obsolete comment in fs.h
  Sanitize f_flags helpers
  Fix f_flags/f_mode in case of lookup_instantiate_filp() from open(pathname, 3)
  anonfd: Allow making anon files read-only
  fs/compat_ioctl.c: fix build error when !BLOCK
  pohmelfs needs I_LOCK
  alloc_file(): simplify handling of mnt_clone_write() errors

* 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/dvrabel/uwb:
  MAINTAINERS: update entries for WUSB, UWB and WLP subsystems

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (36 commits)
  powerpc/gc/wii: Remove get_irq_desc()
  powerpc/gc/wii: hlwd-pic: convert irq_desc.lock to raw_spinlock
  powerpc/gamecube/wii: Fix off-by-one error in ugecon/usbgecko_udbg
  powerpc/mpic: Fix problem that affinity is not updated
  powerpc/mm: Fix stupid bug in subpge protection handling
  powerpc/iseries: use DECLARE_COMPLETION_ONSTACK for non-constant completion
  powerpc: Fix MSI support on U4 bridge PCIe slot
  powerpc: Handle VSX alignment faults correctly in little-endian mode
  powerpc/mm: Fix typo of cpumask_clear_cpu()
  powerpc/mm: Fix hash_utils_64.c compile errors with DEBUG enabled.
  powerpc: Convert BUG() to use unreachable()
  powerpc/pseries: Make declarations of cpu_hotplug_driver_lock() ANSI compatible.
  powerpc/pseries: Don't panic when H_PROD fails during cpu-online.
  powerpc/mm: Fix a WARN_ON() with CONFIG_DEBUG_PAGEALLOC and CONFIG_DEBUG_VM
  powerpc/defconfigs: Set HZ=100 on pseries and ppc64 defconfigs
  powerpc/defconfigs: Disable token ring in powerpc defconfigs
  powerpc/defconfigs: Reduce 64bit vmlinux by making acenic and cramfs modules
  powerpc/pseries: Select XICS and PCI_MSI PSERIES
  powerpc/85xx: Wrong variable returned on error
  powerpc/iseries: Convert to proc_fops
  ...

Fix the cx23888 driver to use the new kfifo API.  Using kfifo_reset()
may result in a possible race conditions.  This patch fixes it by using
a spinlock around the kfifo_reset() function.
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Reviewed-by: NAndy Walls <awalls@radix.net>
Acked-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add kfifo_in_rec() - puts some record data into the FIFO
 Add kfifo_out_rec() - gets some record data from the FIFO
 Add kfifo_from_user_rec() - puts some data from user space into the FIFO
 Add kfifo_to_user_rec() - gets data from the FIFO and write it to user space
 Add kfifo_peek_rec() - gets the size of the next FIFO record field
 Add kfifo_skip_rec() - skip the next fifo out record
 Add kfifo_avail_rec() - determinate the number of bytes available in a record FIFO
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add kfifo_reset_out() for save lockless discard the fifo output
 Add kfifo_skip() to skip a number of output bytes
 Add kfifo_from_user() to copy user space data into the fifo
 Add kfifo_to_user() to copy fifo data to user space
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add DECLARE_KFIFO - macro to declare a kfifo and the associated buffer inside a struct
 Add INIT_KFIFO - Initialize a kfifo declared by DECLARED_KFIFO
 Add DEFINE_KFIFO - macro to define and initialize a kfifo as a global or local object
 Add kfifo_size() - returns the size of the fifo in bytes
 Add kfifo_is_empty() - returns true if the fifo is empty
 Add kfifo_is_full() - returns true if the fifo is full
 Add kfifo_avail() - returns the number of bytes available in the FIFO
 Do some code cleanup
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the "ignoring return value of '...', declared with attribute
warn_unused_result" compiler warning in several users of the new kfifo
API.

It removes the __must_check attribute from kfifo_in() and
kfifo_in_locked() which must not necessary performed.

Fix the allocation bug in the nozomi driver file, by moving out the
kfifo_alloc from the interrupt handler into the probe function.

Fix the kfifo_out() and kfifo_out_locked() users to handle a unexpected
end of fifo.
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

rename kfifo_put...  into kfifo_in...  to prevent miss use of old non in
kernel-tree drivers

ditto for kfifo_get...  -> kfifo_out...

Improve the prototypes of kfifo_in and kfifo_out to make the kerneldoc
annotations more readable.

Add mini "howto porting to the new API" in kfifo.h
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

change name of __kfifo_* functions to kfifo_*, because the prefix __kfifo
should be reserved for internal functions only.
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the pointer to the spinlock out of struct kfifo.  Most users in
tree do not actually use a spinlock, so the few exceptions now have to
call kfifo_{get,put}_locked, which takes an extra argument to a
spinlock.
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a new generic kernel FIFO implementation.

The current kernel fifo API is not very widely used, because it has to
many constrains.  Only 17 files in the current 2.6.31-rc5 used it.
FIFO's are like list's a very basic thing and a kfifo API which handles
the most use case would save a lot of development time and memory
resources.

I think this are the reasons why kfifo is not in use:

 - The API is to simple, important functions are missing
 - A fifo can be only allocated dynamically
 - There is a requirement of a spinlock whether you need it or not
 - There is no support for data records inside a fifo

So I decided to extend the kfifo in a more generic way without blowing up
the API to much.  The new API has the following benefits:

 - Generic usage: For kernel internal use and/or device driver.
 - Provide an API for the most use case.
 - Slim API: The whole API provides 25 functions.
 - Linux style habit.
 - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros
 - Direct copy_to_user from the fifo and copy_from_user into the fifo.
 - The kfifo itself is an in place member of the using data structure, this save an
   indirection access and does not waste the kernel allocator.
 - Lockless access: if only one reader and one writer is active on the fifo,
   which is the common use case, no additional locking is necessary.
 - Remove spinlock - give the user the freedom of choice what kind of locking to use if
   one is required.
 - Ability to handle records. Three type of records are supported:
   - Variable length records between 0-255 bytes, with a record size
     field of 1 bytes.
   - Variable length records between 0-65535 bytes, with a record size
     field of 2 bytes.
   - Fixed size records, which no record size field.
 - Preserve memory resource.
 - Performance!
 - Easy to use!

This patch:

Since most users want to have the kfifo as part of another object,
reorganize the code to allow including struct kfifo in another data
structure.  This requires changing the kfifo_alloc and kfifo_init
prototypes so that we pass an existing kfifo pointer into them.  This
patch changes the implementation and all existing users.

[akpm@linux-foundation.org: fix warning]
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Clean up typos/grammos/spellos in events-kmem.txt.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warnings (@arg name) in string.c::skip_spaces().

  Warning(lib/string.c:347): No description found for parameter 'str'
  Warning(lib/string.c:347): Excess function parameter 's' description in 'skip_spaces'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit 7bc7d637, as
requested by John Stultz. Quoting John:

 "Petr Titěra reported an issue where he saw odd atime regressions with
  2.6.33 where there were a full second worth of nanoseconds in the
  nanoseconds field.

  He also reviewed the time code and narrowed down the problem: unhandled
  overflow of the nanosecond field caused by rounding up the
  sub-nanosecond accumulated time.

  Details:

   * At the end of update_wall_time(), we currently round up the
  sub-nanosecond portion of accumulated time when storing it into xtime.
  This was added to avoid time inconsistencies caused when the
  sub-nanosecond portion was truncated when storing into xtime.
  Unfortunately we don't handle the possible second overflow caused by
  that rounding.

   * Previously the xtime_cache code hid this overflow by normalizing the
  xtime value when storing into the xtime_cache.

   * We could try to handle the second overflow after the rounding up, but
  since this affects the timekeeping's internal state, this would further
  complicate the next accumulation cycle, causing small errors in ntp
  steering. As much as I'd like to get rid of it, the xtime_cache code is
  known to work.

   * The correct fix is really to include the sub-nanosecond portion in the
  timekeeping accessor function, so we don't need to round up at during
  accumulation. This would greatly simplify the accumulation code.
  Unfortunately, we can't do this safely until the last three
  non-GENERIC_TIME arches (sparc32, arm, cris) are converted  (those
  patches are in -mm) and we kill off the spots where arches set xtime
  directly. This is all 2.6.34 material, so I think reverting the
  xtime_cache change is the best approach for now.

  Many thanks to Petr for both reporting and finding the issue!"
Reported-by: NPetr Titěra <P.Titera@century.cz>
Requested-by: Njohn stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch (as1318) updates the runtime PM documentation, adding a
section discussing the interaction between runtime PM and system sleep.

[rjw: Rebased and made it agree with the other updates better.]
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

The power management of some devices is handled through device types
and device classes rather than through bus types.  Since these
devices may also benefit from using the run-time power management
core, extend it so that the device type and device class run-time PM
callbacks can be taken into consideration by it if the bus type
callback is not defined.

Update the run-time PM core documentation to reflect this change.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

loff_t is a type that isn't entirely dependant upon 32 v 64bit choice
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This question was determined to be a bug which was fixed in
commit 4a3b0a49.
Signed-off-by: NAndreas Gruenbacher <agruen@suse.de>
Cc: Jan Blunck <jblunck@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* pull ACC_MODE to fs.h; we have several copies all over the place
* nightmarish expression calculating f_mode by f_flags deserves a helper
too (OPEN_FMODE(flags))
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just set f_flags when shoving struct file into nameidata; don't
postpone that until __dentry_open().  do_filp_open() has correct
value; lookup_instantiate_filp() doesn't - we lose the difference
between O_RDWR and 3 by that point.

We still set .intent.open.flags, so no fs code needs to be changed.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It seems a couple places such as arch/ia64/kernel/perfmon.c and
drivers/infiniband/core/uverbs_main.c could use anon_inode_getfile()
instead of a private pseudo-fs + alloc_file(), if only there were a way
to get a read-only file.  So provide this by having anon_inode_getfile()
create a read-only file if we pass O_RDONLY in flags.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

No driver uses SG_SET_TRANSFORM any more in Linux, since the ide-scsi
driver was removed in 2.6.29. The compat-ioctl cleanup series moved
the handling for this around, which broke building without CONFIG_BLOCK.

Just remove the code handling it for compat mode.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Kill debugging printk in question
Signed-off-by: NEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

When alloc_file() and init_file() were combined, the error handling of
mnt_clone_write() was taken into alloc_file() in a somewhat obfuscated
way.  Since we don't use the error code for anything except warning,
we might as well warn directly without an extra variable.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Update the file patterns for the WUSB, UWB and WLP subsystems and add
netdev@vger as the list for the WLP subsystem.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>

By default, the PATA pins are routed to the async address lines in which
case, no peripheral muxing needs to be done.  However, if the pins get
routed through the GPIO PORTs pins, we need to make sure to request them
so that the muxing is properly set up.
Signed-off-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>