o During some testing I did following and noticed throttling stops working.

        - Put a very low limit on a cgroup, say 1 byte per second.
        - Start some reads, this will set slice_end to a very high value.
        - Change the limit to higher value say 1MB/s
        - Now IO unthrottles and finishes as expected.
        - Try to do the read again but IO is not limited to 1MB/s as expected.

o What is happening.
        - Initially low value of limit sets slice_end to a very high value.
        - During updation of limit, slice_end is not being truncated.
        - Very high value of slice_end leads to keeping the existing slice
          valid for a very long time and new slice does not start.
        - tg_may_dispatch() is called in blk_throtle_bio(), and trim_slice()
          is not called in this path. So slice_start is some old value and
          practically we are able to do huge amount of IO.

o There are many ways it can be fixed. I have fixed it by trying to
  adjust/cleanup slice_end in trim_slice(). Generally we extend slices if bio
  is big and can't be dispatched in one slice. After dispatch of bio, readjust
  the slice_end to make sure we don't end up with huge values.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

commit 9284bcf4 checks for proper length of iov entries in
blk_rq_map_user_iov(). But if the map is unaligned, kernel
will break out the loop without checking for the proper length.
So we need to check the proper length before the unalign check.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

In commit 9b7f76dc37919ea36caa9680a3f765e5b19b25fb,
 Author: Lars Ellenberg <lars.ellenberg@linbit.com>
 Date:   Wed Aug 11 23:40:24 2010 +0200

    drbd: new configuration parameter c-min-rate

a bad chunk slipped through, which is now reverted as well,
restoring the correct irqsave for the endio callback.

This patch also add comments at both req_mod()
and in the endio callback so it should not happen again.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

This should fix a performance degradation we observed recently.

If we don't expect any subheader, we should not call into the tcp stack,
as that may add considerable latency if there is no data available at
this point.

For a synthetic synchronous write load with single outstanding writes,
this additional latency when processing the "unplug remote" packet
added up to a performance degradation factor >= 10.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
  NFS: Ensure we return the dirent->d_type when it is known
  NFS: Correct the array bound calculation in nfs_readdir_add_to_array
  NFS: Don't ignore errors from nfs_do_filldir()
  NFS: Fix the error handling in "uncached_readdir()"
  NFS: Fix a page leak in uncached_readdir()
  NFS: Fix a page leak in nfs_do_filldir()
  NFS: Assume eof if the server returns no readdir records
  NFS: Buffer overflow in ->decode_dirent() should not be fatal
  Pure nfs client performance using odirect.
  SUNRPC: Fix an infinite loop in call_refresh/call_refreshresult

* 'linux-next' of git://git.infradead.org/ubi-2.6:
  UBI: release locks in check_corruption

Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  posix-cpu-timers: Rcu_read_lock/unlock protect find_task_by_vpid call

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  dmar, x86: Use function stubs when CONFIG_INTR_REMAP is disabled
  x86-64: Fix and clean up AMD Fam10 MMCONF enabling
  x86: UV: Address interrupt/IO port operation conflict
  x86: Use online node real index in calulate_tbl_offset()
  x86, asm: Fix binutils 2.15 build failure

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf symbols: Remove incorrect open-coded container_of()
  perf record: Handle restrictive permissions in /proc/{kallsyms,modules}
  x86/kprobes: Prevent kprobes to probe on save_args()
  irq_work: Drop cmpxchg() result
  perf: Fix owner-list vs exit
  x86, hw_nmi: Move backtrace_mask declaration under ARCH_HAS_NMI_WATCHDOG
  tracing: Fix recursive user stack trace
  perf,hw_breakpoint: Initialize hardware api earlier
  x86: Ignore trap bits on single step exceptions
  tracing: Force arch_local_irq_* notrace for paravirt
  tracing: Fix module use of trace_bprintk()

Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix idle balancing
  sched: Fix volanomark performance regression

* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
  [S390] qdio: free indicator after reset is finished
  [S390] nmi: fix clock comparator revalidation

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cciss: fix build for PROC_FS disabled
  block: fix amiga and atari floppy driver compile warning
  blk-throttle: Fix calculation of max number of WRITES to be dispatched
  ioprio: grab rcu_read_lock in sys_ioprio_{set,get}()
  xen/blkfront: cope with backend that fail empty BLKIF_OP_WRITE_BARRIER requests
  xen/blkfront: Implement FUA with BLKIF_OP_WRITE_BARRIER
  xen/blkfront: change blk_shadow.request to proper pointer
  xen/blkfront: map REQ_FLUSH into a full barrier

Merge branch 'rmobile-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6

* 'rmobile-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
  ARM: mach-shmobile: clock-sh7372: remove bogus pllc2 clock toggling.
  ARM: mach-shmobile: clock-sh7372: remove unnecessary fsi clocks
  ARM: mach-shmobile: clock-sh7372: modify error code
  ARM: mach-shmobile: ap4evb: FSI clock use proper process for ak4642
  ARM: mach-shmobile: ap4evb: FSI clock use proper process for HDMI
  ARM: mach-shmobile: clock-sh7372: remove fsidiv bogus disable
  ARM: mach-shmobile: sh7372 USB0/IIC1 MSTP fix

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc:
  mmc: sdhci: 8-bit bus width changes
  mmc: sdio: fix runtime PM anomalies by introducing MMC_CAP_POWER_OFF_CARD
  mmc: sdio: fix nasty oops in mmc_sdio_detect
  mmc: omap4: hsmmc: Fix improper card detection while booting
  mmc: fix rmmod race for hosts using card-detection polling
  mmc: sdhci: Fix crash on boot with C0 stepping Moorestown platforms
  mmc: sdhci-esdhc-imx: enable QUIRK_NO_MULTIBLOCK only for i.MX25 and i.MX35
  mmc: sdhci-esdhc-imx: fix timeout on i.MX's sdhci
  mmc: sdhci: Properly enable SDIO IRQ wakeups
  mmc: ushc: Return proper error code for ushc_probe()
  mmc: Fix printing of card DDR type

Merge branch 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung

* 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
  ARM: S5PV210: Fix sysdev related warning messages
  ARM: S3C24XX: Fix UART3 submask on S3C2416 and S3C2443
  ARM: S3C24XX: Fix Demux error in UART3 irqs on S3C2443 and S3C2416
  ARM: S3C64XX: fix uart clock setup for mini6410/real6410
  ARM: S3C24XX: Fix wrong s3c_gpio_cfgpull
  ARM: S3C2410: Adapt h1940-bluetooth to gpiolib changes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
  nilfs2: fix typo in comment of nilfs_dat_move function
  nilfs2: nilfs_iget_for_gc() returns ERR_PTR

The stubs for CONFIG_INTR_REMAP disabled need to be functions
instead of values to eliminate build warnings.

 arch/x86/kernel/apic/apic.c: In function 'lapic_suspend':
 arch/x86/kernel/apic/apic.c:2060:3: warning: statement with no effect
 arch/x86/kernel/apic/apic.c: In function 'lapic_resume':
 arch/x86/kernel/apic/apic.c:2137:3: warning: statement with no effect
Reported-and-Tested-by: Fabio Comolli <fabio.comolli@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <20101122124834.74429004.randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

The qdio device indicator is freed before the device is notified that
the indicator is reset. This sequence contains a race when the freed
indicator is used by a new device while the reset of the indicator is
still pending. Do the reset operation before freeing the indicator to
avoid that potential race.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

On each machine check all registers are revalidated. The save area for
the clock comparator however only contains the upper most seven bytes
of the former contents, if valid.
Therefore the machine check handler uses a store clock instruction to
get the current time and writes that to the clock comparator register
which in turn will generate an immediate timer interrupt.
However within the lowcore the expected time of the next timer
interrupt is stored. If the interrupt happens before that time the
handler won't be called. In turn the clock comparator won't be
reprogrammed and therefore the interrupt condition stays pending which
causes an interrupt loop until the expected time is reached.

On NOHZ machines this can result in unresponsive machines since the
time of the next expected interrupted can be a couple of days in the
future.

To fix this just revalidate the clock comparator register with the
expected value.
In addition the special handling for udelay must be changed as well.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

This patch fixes following warning messages when CONFIG_PM selected.

In file included from arch/arm/mach-s5pv210/mach-smdkv210.c:34:
arch/arm/plat-samsung/include/plat/pm.h:104: warning: 'struct sys_device'
declared inside parameter list
arch/arm/plat-samsung/include/plat/pm.h:104: warning: its scope is only this
definition or declaration, which is probably not what you want
arch/arm/plat-samsung/include/plat/pm.h:105: warning: 'struct sys_device'
declared inside parameter list

In file included from arch/arm/mach-s5pv210/mach-smdkc110.c:31:
arch/arm/plat-samsung/include/plat/pm.h:104: warning: 'struct sys_device'
declared inside parameter list
arch/arm/plat-samsung/include/plat/pm.h:104: warning: its scope is only this
definition or declaration, which is probably not what you want
arch/arm/plat-samsung/include/plat/pm.h:105: warning: 'struct sys_device'
declared inside parameter list
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

The UART3 submask should be 0x7 (SUBSRCPND[26:24]).
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

IRQ_S3C2443_UART3 is being used as the base when it should actually
be IRQ_S3C2443_RX3 on S3C2443 and S3C2416 for the UART3.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

Don't rewrite clock config in UCON preconfigured by
bootloader. No need to set 10th bit in UCON because
[11:10] 2'b00 means source clock is PCLK too.
If set, console does not work if bootloader
has preconfigured [11:10] with 2'b00.
If not set, console works with any bootloader
config value (2'bxx).
More information about clock setup in UCON is available
in "S3C6410X RISC Microprocessor User's Manual,
Revision 1.20" p. 31-13 (Chapter 31.6.2
UART CONTROL REGISTER).
Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

This patch fixes wrong s3c_gpio_cfgpull with s3c_gpio_setpull.

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

Replace in s3c_gpio_cfgpull with s3c_gpio_setpull.
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: (lis3lv02d_i2c) Fix compile warnings
  hwmon: (i5k_amb) Fix compile warning

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: remove duplicated #include
  xen: x86/32: perform initial startup on initial_page_table

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: fix memchr() not to dereference memory for zero length
  arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly
  arch/tile: fix rwlock so would-be write lockers don't block new readers

* 'drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  pci root complex: support for tile architecture
  drivers/net/tile/: on-chip network drivers for the tile architecture
  MAINTAINERS: add drivers/char/hvc_tile.c as maintained by tile

* master.kernel.org:/home/rmk/linux-2.6-arm:
  ARM: 6482/2: Fix find_next_zero_bit and related assembly
  ARM: 6490/1: MM: bugfix: initialize spinlock for init_mm.context
  ARM: avoid annoying <4>'s in printk output
  SCSI: arm fas216: fix missing ';'
  ARM: avoid marking decompressor .stack section as having contents
  ARM: 6489/1: thumb2: fix incorrect optimisation in usracc
  ARM: 6488/1: nomadik: prevent sched_clock() wraparound
  ARM: 6484/1: fix compile warning in mm/init.c
  ARM: 6473/1: Small update to ux500 specific L2 cache code
  ARM: improve compiler's ability to optimize page tables
  mx25: fix spi device registration typo
  ARM i.MX27 eukrea: Fix compilation
  ARM i.MX spi: fix compilation for i.MX21
  ARM i.MX pcm037 eet: compile fixes
  ARM i.MX: sdma is merged, so remove #ifdef SDMA_IS_MERGED
  ARM mx3fb: check for DMA engine type
  mach-pcm037_eet: Fix section mismatch for eet_init_devices()

Merge branch 'fbdev-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6

* 'fbdev-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6:
  sisfb: delete osdef.h
  sisfb: move the CONFIG warning to sis_main.c
  sisfb: replace SiS_SetMemory with memset_io
  sisfb: remove InPort/OutPort wrappers
  sisfb: use CONFIG_FB_SIS_301/315 instead of SIS301/315H
  sisfb: delete redudant #define SIS_LINUX_KERNEL
  sisfb: delete dead SIS_XORG_XF86 code
  sisfb: delete fallback code for pci_map_rom()
  sisfb: delete obsolete PCI ROM bug workaround
  fbdev: Update documentation index file.
  lxfb: Program panel v/h sync output polarity correctly
  fbcmap: integer overflow bug
  fbcmap: cleanup white space in fb_alloc_cmap()
  MAINTAINERS: Add fbdev patchwork entry, tidy up file patterns.
  fbdev: da8xx: punt duplicated FBIO_WAITFORVSYNC define
  fbdev: sh_mobile_lcdcfb: fix bug in reconfig()

* 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
  sh: clkfwk: Build fix for non-legacy CPG changes.
  sh: Use GCC __builtin_prefetch() to implement prefetch().
  sh: fix vsyscall compilation due to .eh_frame issue
  sh: avoid to flush all cache in sys_cacheflush
  sh: clkfwk: Disable init clk op for non-legacy clocks.
  sh: clkfwk: Kill off now unused algo_id in set_rate op.
  sh: clkfwk: Kill off unused clk_set_rate_ex().

* 'for-linus' of git://neil.brown.name/md:
  md: Call blk_queue_flush() to establish flush/fua support
  md/raid1: really fix recovery looping when single good device fails.
  md: fix return value of rdev_size_change()

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  virtio: fix format of sysfs driver/vendor files
  Char: virtio_console, fix memory leak
  virtio: return correct capacity to users
  module: Update prototype for ref_module (formerly use_module)

When compiling arch/x86/kernel/early_printk_mrst.c with i386
allmodconfig, gcc-4.1.0 generates an out-of-line copy of
__set_fixmap_offset() which contains a reference to
__this_fixmap_does_not_exist which the compiler cannot elide.

Marking __set_fixmap_offset() as __always_inline prevents this.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Feng Tang <feng.tang@intel.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The recent changes to gfp.h to satisfy sparse broke scripts/gfp-translate.
This patch fixes it up to work with old and new versions of gfp.h .

[akpm@linux-foundation.org: use `grep -q', per WANG Cong]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Namhyung Kim <namhyung@gmail.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

reiserfs_unpack() locks the inode mutex with reiserfs_mutex_lock_safe()
to protect against reiserfs lock dependency.  However this protection
requires to have the reiserfs lock to be locked.

This is the case if reiserfs_unpack() is called by reiserfs_ioctl but
not from reiserfs_quota_on() when it tries to unpack tails of quota
files.

Fix the ordering of the two locks in reiserfs_unpack() to fix this
issue.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: Markus Gapp <markus.gapp@gmx.net>
Reported-by: Jan Kara <jack@suse.cz>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: <stable@kernel.org>		[2.6.36.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

According to the comment describing ops_lock in the definition of struct
backlight_device and when comparing with other functions in backlight.c
the mutex must be hold when checking ops to be non-NULL.

Fixes a problem added by c835ee7f ("backlight: Add suspend/resume
support to the backlight core") in Jan 2009.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

struct als_data *data is not used in this driver at all.

Also add a missing ">" character for MODULE_AUTHOR.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently one pagemap_read() call walks in PAGEMAP_WALK_SIZE bytes (== 512
pages.) But there is a corner case where walk_pmd_range() accidentally
runs over a VMA associated with a hugetlbfs file.

For example, when a process has mappings to VMAs as shown below:

  # cat /proc/<pid>/maps
  ...
  3a58f6d000-3a58f72000 rw-p 00000000 00:00 0
  7fbd51853000-7fbd51855000 rw-p 00000000 00:00 0
  7fbd5186c000-7fbd5186e000 rw-p 00000000 00:00 0
  7fbd51a00000-7fbd51c00000 rw-s 00000000 00:12 8614   /hugepages/test

then pagemap_read() goes into walk_pmd_range() path and walks in the range
0x7fbd51853000-0x7fbd51a53000, but the hugetlbfs VMA should be handled by
walk_hugetlb_range().  Otherwise PMD for the hugepage is considered bad
and cleared, which causes undesirable results.

This patch fixes it by separating pagemap walk range into one PMD.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>