I met a odd prblem:read /proc/partitions may return zero.

I wrote a file test.c:
int main()
{
	char buff[4096];
	int ret;
	int fd;
	printf("pid=%d\n",getpid());
	while (1) {
		fd = open("/proc/partitions", O_RDONLY);
		if (fd < 0) {
			printf("open error %s\n", strerror(errno));
			return 0;
		}
		ret = read(fd, buff, 4096);
		if (ret <= 0)
			printf("ret=%d, %s, %ld\n", ret,
				strerror(errno), lseek(fd,0,SEEK_CUR));
		close(fd);
	}
	exit(0);
}

You can reproduce by:
1:while true;do cat /proc/partitions > /dev/null ;done
2:./test

I reviewed the code and found:

>> static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
>> {
>> 	static void *p;
>>
>> 	p = disk_seqf_start(seqf, pos);
>> 	if (!IS_ERR_OR_NULL(p) && !*pos)
>> 		seq_puts(seqf, "major minor  #blocks  name\n\n");
>> 	return p;
>> }
		test								cat /proc/partitions
	p = disk_seqf_start()(Not NULL)
									p = disk_seqf_start()(NULL because pos)
	if (!IS_ERR_OR_NULL(p) && !*pos)
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add a helper to map a bio to a scatterlist, modelled after
blk_rq_map_sg.

This helper is useful for any driver that wants to create
a scatterlist from its ->make_request_fn method.

Changes in v2:
 - Use __blk_segment_map_sg to avoid duplicated code
 - Add cocbook style function comment

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Split the mapping code in blk_rq_map_sg() to a helper
__blk_segment_map_sg(), so that other mapping function, e.g.
blk_bio_map_sg(), can share the code.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Suggested-by: Jens Axboe <axboe@kernel.dk>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

For regular file, write operaion used blk_plug function.But for block
file,write operation did not use blk_plug.
This patch is also for write-cache mode for block-device.
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When a disk has large discard_granularity and small max_discard_sectors,
discards are not split with optimal alignment.  In the limit case of
discard_granularity == max_discard_sectors, no request could be aligned
correctly, so in fact you might end up with no discarded logical blocks
at all.

Another example that helps showing the condition in the patch is with
discard_granularity == 64, max_discard_sectors == 128.  A request that is
submitted for 256 sectors 2..257 will be split in two: 2..129, 130..257.
However, only 2 aligned blocks out of 3 are included in the request;
128..191 may be left intact and not discarded.  With this patch, the
first request will be truncated to ensure good alignment of what's left,
and the split will be 2..127, 128..255, 256..257.  The patch will also
take into account the discard_alignment.

At most one extra request will be introduced, because the first request
will be reduced by at most granularity-1 sectors, and granularity
must be less than max_discard_sectors.  Subsequent requests will run
on round_down(max_discard_sectors, granularity) sectors, as in the
current code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Mostly a preparation for the next patch.

In principle this fixes an infinite loop if max_discard_sectors < granularity,
but that really shouldn't happen.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull MIPS updates from Ralf Baechle:
 "The lion share of this pull request are fixes for clk-related breakage
  caused by other changes during this merge window.  For some platforms
  the fix was as simple as selecting HAVE_CLK, for others like the
  Loongson 2 significant restructuring was required.

  The remainder are changes required to get the Lantiq code to work
  again."

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Loongson 2: Sort out clock managment.
  MIPS: Loongson 1: more clk support and add select HAVE_CLK
  MIPS: txx9: Fix redefinition of clk_* by adding select HAVE_CLK
  MIPS: BCM63xx: Fix redefinition of clk_* by adding select HAVE_CLK
  MIPS: AR7: Fix redefinition of clk_* by adding select HAVE_CLK
  MIPS: Lantiq: Platform specific CLK fixup
  MIPS: Lantiq: Add device_tree_init function
  MIPS: Lantiq: Fix interface clock and PCI control register offset

Pull UML fixes from Richard Weinberger:
 "This patch set contains mostly fixes and cleanups.  The UML tty driver
  uses now tty_port and is no longer broken like hell  :-)"

* 'for-linus-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Add arch/x86/um to MAINTAINERS
  um: pass siginfo to guest process
  um: fix ubd_file_size for read-only files
  um: pull interrupt_end() into userspace()
  um: split syscall_trace(), pass pt_regs to it
  um: switch UPT_SET_RETURN_VALUE and regs_return_value to pt_regs
  um: set BLK_CGROUP=y in defconfig
  um: remove count_lock
  um: fully use tty_port
  um: Remove dead code
  um: remove line_ioctl()
  TTY: um/line, use tty from tty_port
  TTY: um/line, add tty_port

Pull ARM DMA engine updates from Russell King:
 "This looks scary at first glance, but what it is is:
   - a rework of the sa11x0 DMA engine driver merged during the previous
     cycle, to extract a common set of helper functions for DMA engine
     implementations.
   - conversion of amba-pl08x.c to use these helper functions.
   - addition of OMAP DMA engine driver (using these helper functions),
     and conversion of some of the OMAP DMA users to use DMA engine.

  Nothing in the helper functions is ARM specific, so I hope that other
  implementations can consolidate some of their code by making use of
  these helpers.

  This has been sitting in linux-next most of the merge cycle, and has
  been tested by several OMAP folk.  I've tested it on sa11x0 platforms,
  and given it my best shot on my broken platforms which have the
  amba-pl08x controller.

  The last point is the addition to feature-removal-schedule.txt, which
  will have a merge conflict.  Between myself and TI, we're planning to
  remove the old TI DMA implementation next year."

Fix up trivial add/add conflicts in Documentation/feature-removal-schedule.txt
and drivers/dma/{Kconfig,Makefile}

* 'dmaengine' of git://git.linaro.org/people/rmk/linux-arm: (53 commits)
  ARM: 7481/1: OMAP2+: omap2plus_defconfig: enable OMAP DMA engine
  ARM: 7464/1: mmc: omap_hsmmc: ensure probe returns error if DMA channel request fails
  Add feature removal of old OMAP private DMA implementation
  mtd: omap2: remove private DMA API implementation
  mtd: omap2: add DMA engine support
  spi: omap2-mcspi: remove private DMA API implementation
  spi: omap2-mcspi: add DMA engine support
  ARM: omap: remove mmc platform data dma_mask and initialization
  mmc: omap: remove private DMA API implementation
  mmc: omap: add DMA engine support
  mmc: omap_hsmmc: remove private DMA API implementation
  mmc: omap_hsmmc: add DMA engine support
  dmaengine: omap: add support for cyclic DMA
  dmaengine: omap: add support for setting fi
  dmaengine: omap: add support for returning residue in tx_state method
  dmaengine: add OMAP DMA engine driver
  dmaengine: sa11x0-dma: add cyclic DMA support
  dmaengine: sa11x0-dma: fix DMA residue support
  dmaengine: PL08x: ensure all descriptors are freed when channel is released
  dmaengine: PL08x: get rid of write only pool_ctr and free_txd locking
  ...

Pull ARM audit/signal updates from Russell King:
 "ARM audit/signal handling updates from Al and Will.  This improves on
  the work Viro did last merge window, and sorts out some of the issues
  found with that work."

* 'audit' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7475/1: sys_trace: allow all syscall arguments to be updated via ptrace
  ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS
  ARM: 7473/1: deal with handlerless restarts without leaving the kernel
  ARM: 7472/1: pull all work_pending logics into C function
  ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline""
  ARM: 7470/1: Revert "7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK""

Pull ARM fixes from Russell King:
 "This fixes various issues found during July"

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7479/1: mm: avoid NULL dereference when flushing gate_vma with VIVT caches
  ARM: Fix undefined instruction exception handling
  ARM: 7480/1: only call smp_send_stop() on SMP
  ARM: 7478/1: errata: extend workaround for erratum #720789
  ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP
  ARM: 7476/1: vfp: only clear vfp state for current cpu in vfp_pm_suspend
  ARM: 7468/1: ftrace: Trace function entry before updating index
  ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+
  ARM: 7466/1: disable interrupt before spinning endlessly
  ARM: 7465/1: Handle >4GB memory sizes in device tree and mem=size@start option

Signed-off-by: Richard Weinberger <richard@nod.at>

UML guest processes now get correct siginfo_t for SIGTRAP, SIGFPE,
SIGILL and SIGBUS. Specifically, si_addr and si_code are now correct
where previously they were si_addr = NULL and si_code = 128.
Signed-off-by: Martin Pärtel <martin.partel@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Made ubd_file_size not request write access. Fixes use of read-only images.
Signed-off-by: Martin Pärtel <martin.partel@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[richard@nod.at: Fixed some minor build issues]
Signed-off-by: Richard Weinberger <richard@nod.at>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

Pull fbdev updates from Florian Tobias Schandinat:
 - large updates for OMAP
   - support for LCD3 overlay manager (omap5)
   - omapdss output cleanup
   - removal of passive matrix LCD support as there are no drivers for
     such panels for DSS or DSS2 and nobody complained (cleanup)
 - large updates for SH Mobile
   - overlay support
   - separating MERAM (cache) from framebuffer driver
 - some updates for Exynos and da8xx-fb
 - various other small patches

* tag 'fbdev-updates-for-3.6' of git://github.com/schandinat/linux-2.6: (78 commits)
  da8xx-fb: fix compile issue due to missing include
  fbdev: Make pixel_to_pat() failure mode more friendly
  da8xx-fb: do not turn ON LCD backlight unless LCDC is enabled
  fbdev: sh_mobile_lcdc: Fix vertical panning step
  video: exynos mipi dsi: Fix mipi dsi regulators handling issue
  video: da8xx-fb: do clock reset of revision 2 LCDC before enabling
  arm: da850: configure LCDC fifo threshold
  video: da8xx-fb: configure FIFO threshold to reduce underflow errors
  video: da8xx-fb: fix flicker due to 1 frame delay in updated frame
  video: da8xx-fb rev2: fix disabling of palette completion interrupt
  da8xx-fb: add missing FB_BLANK operations
  video: exynos_dp: use usleep_range instead of delay
  video: exynos_dp: check the only INTERLANE_ALIGN_DONE bit during Link Training
  fb: epson1355fb: Fix section mismatch
  video: exynos_dp: fix wrong DPCD address during Link Training
  video/smscufx: fix line counting in fb_write
  aty128fb: Fix coding style issues
  fbdev: sh_mobile_lcdc: Fix pan offset computation in YUV mode
  fbdev: sh_mobile_lcdc: Fix overlay registers update during pan operation
  fbdev: sh_mobile_lcdc: Support horizontal panning
  ...

Pull sound fixes from Takashi Iwai:
 "A collection of small fixes that have been found recently.  Most of
  the commits are regression fixes in HD-audio and some other random
  drivers."

* tag 'sound-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: snd-usb: fix clock source validity index
  ALSA: hda - Fix mute-LED GPIO initialization for IDT codecs
  ALSA: hda - Add descriptions for missing IDT 92HD83x models
  ALSA: hda - Fix polarity of mute LED on HP Mini 210
  ALSA: es1688 - freeup resources on init failure
  ALSA: hda - Workaround for silent output on VAIO Z with ALC889
  ALSA: hda - Fix WARNING from HDMI/DP parser
  ALSA: hda - Detach from converter at closing in patch_hdmi.c
  ALSA: hda - Fix mute-LED GPIO setup for HP Mini 210
  ALSA: mpu401: Fix missing initialization of irq field
  ALSA: hda - Fix invalid D3 of headphone DAC on VT202x codecs

Pull second vfs pile from Al Viro:
 "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
  deadlock reproduced by xfstests 068), symlink and hardlink restriction
  patches, plus assorted cleanups and fixes.

  Note that another fsfreeze deadlock (emergency thaw one) is *not*
  dealt with - the series by Fernando conflicts a lot with Jan's, breaks
  userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
  for massive vfsmount leak; this is going to be handled next cycle.
  There probably will be another pull request, but that stuff won't be
  in it."

Fix up trivial conflicts due to unrelated changes next to each other in
drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
  delousing target_core_file a bit
  Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
  fs: Remove old freezing mechanism
  ext2: Implement freezing
  btrfs: Convert to new freezing mechanism
  nilfs2: Convert to new freezing mechanism
  ntfs: Convert to new freezing mechanism
  fuse: Convert to new freezing mechanism
  gfs2: Convert to new freezing mechanism
  ocfs2: Convert to new freezing mechanism
  xfs: Convert to new freezing code
  ext4: Convert to new freezing mechanism
  fs: Protect write paths by sb_start_write - sb_end_write
  fs: Skip atime update on frozen filesystem
  fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
  fs: Improve filesystem freezing handling
  switch the protection of percpu_counter list to spinlock
  nfsd: Push mnt_want_write() outside of i_mutex
  btrfs: Push mnt_want_write() outside of i_mutex
  fat: Push mnt_want_write() outside of i_mutex
  ...

For unexplainable reasons the Loongson 2 clock API was implemented in a
module so fixing this involved shifting large amounts of code around.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Pull block driver changes from Jens Axboe:

 - Making the plugging support for drivers a bit more sane from Neil.
   This supersedes the plugging change from Shaohua as well.

 - The usual round of drbd updates.

 - Using a tail add instead of a head add in the request completion for
   ndb, making us find the most completed request more quickly.

 - A few floppy changes, getting rid of a duplicated flag and also
   running the floppy init async (since it takes forever in boot terms)
   from Andi.

* 'for-3.6/drivers' of git://git.kernel.dk/linux-block:
  floppy: remove duplicated flag FD_RAW_NEED_DISK
  blk: pass from_schedule to non-request unplug functions.
  block: stack unplug
  blk: centralize non-request unplug handling.
  md: remove plug_cnt feature of plugging.
  block/nbd: micro-optimization in nbd request completion
  drbd: announce FLUSH/FUA capability to upper layers
  drbd: fix max_bio_size to be unsigned
  drbd: flush drbd work queue before invalidate/invalidate remote
  drbd: fix potential access after free
  drbd: call local-io-error handler early
  drbd: do not reset rs_pending_cnt too early
  drbd: reset congestion information before reporting it in /proc/drbd
  drbd: report congestion if we are waiting for some userland callback
  drbd: differentiate between normal and forced detach
  drbd: cleanup, remove two unused global flags
  floppy: Run floppy initialization asynchronous

Pull core block IO bits from Jens Axboe:
 "The most complicated part if this is the request allocation rework by
  Tejun, which has been queued up for a long time and has been in
  for-next ditto as well.

  There are a few commits from yesterday and today, mostly trivial and
  obvious fixes.  So I'm pretty confident that it is sound.  It's also
  smaller than usual."

* 'for-3.6/core' of git://git.kernel.dk/linux-block:
  block: remove dead func declaration
  block: add partition resize function to blkpg ioctl
  block: uninitialized ioc->nr_tasks triggers WARN_ON
  block: do not artificially constrain max_sectors for stacking drivers
  blkcg: implement per-blkg request allocation
  block: prepare for multiple request_lists
  block: add q->nr_rqs[] and move q->rq.elvpriv to q->nr_rqs_elvpriv
  blkcg: inline bio_blkcg() and friends
  block: allocate io_context upfront
  block: refactor get_request[_wait]()
  block: drop custom queue draining used by scsi_transport_{iscsi|fc}
  mempool: add @gfp_mask to mempool_create_node()
  blkcg: make root blkcg allocation use %GFP_KERNEL
  blkcg: __blkg_lookup_create() doesn't need radix preload

Pull md updates from NeilBrown.

* 'for-next' of git://neil.brown.name/md:
  DM RAID: Add support for MD RAID10
  md/RAID1: Add missing case for attempting to repair known bad blocks.
  md/raid5: For odirect-write performance, do not set STRIPE_PREREAD_ACTIVE.
  md/raid1: don't abort a resync on the first badblock.
  md: remove duplicated test on ->openers when calling do_md_stop()
  raid5: Add R5_ReadNoMerge flag which prevent bio from merging at block layer
  md/raid1: prevent merging too large request
  md/raid1: read balance chooses idlest disk for SSD
  md/raid1: make sequential read detection per disk based
  MD RAID10: Export md_raid10_congested
  MD: Move macros from raid1*.h to raid1*.c
  MD RAID1: rename mirror_info structure
  MD RAID10: rename mirror_info structure
  MD RAID10: Fix compiler warning.
  raid5: add a per-stripe lock
  raid5: remove unnecessary bitmap write optimization
  raid5: lockless access raid5 overrided bi_phys_segments
  raid5: reduce chance release_stripe() taking device_lock

In commit 3b6e2723 ("locks: prevent side-effects of
locks_release_private before file_lock is initialized") we removed the
last user of lm_release_private without removing the field itself.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This fixes a redefinition of clk_*:

arch/mips/loongson1/common/clock.c:23:13: error: redefinition of 'clk_get'
include/linux/clk.h:281:27: note: previous definition of 'clk_get' was here
arch/mips/loongson1/common/clock.c:41:15: error: redefinition of 'clk_get_rate'
include/linux/clk.h:302:29: note: previous definition of 'clk_get_rate' was here
make[3]: *** [arch/mips/loongson1/common/clock.o] Error 1
Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips@linux-mips.org
Reviewed-by: John Crispin <blogic@openwrt.org>
Acked-by: Kelvin Cheung <keguang.zhang@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/4143/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/txx9/generic/setup.c:87:13: error: redefinition of 'clk_get'
include/linux/clk.h:281:27: note: previous definition of 'clk_get' was here
arch/mips/txx9/generic/setup.c:97:5: error: redefinition of 'clk_enable'
include/linux/clk.h:295:19: note: previous definition of 'clk_enable' was here
arch/mips/txx9/generic/setup.c:103:6: error: redefinition of 'clk_disable'
include/linux/clk.h:300:20: note: previous definition of 'clk_disable' was here
arch/mips/txx9/generic/setup.c:108:15: error: redefinition of 'clk_get_rate'
include/linux/clk.h:302:29: note: previous definition of 'clk_get_rate' was here
arch/mips/txx9/generic/setup.c:114:6: error: redefinition of 'clk_put'
include/linux/clk.h:291:20: note: previous definition of 'clk_put' was here
make[3]: *** [arch/mips/txx9/generic/setup.o] Error 1
Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips@linux-mips.org
Reviewed-by: John Crispin <blogic@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/4142/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm63xx/clk.c:249:5: error: redefinition of 'clk_enable'
include/linux/clk.h:295:19: note: previous definition of 'clk_enable' was here
arch/mips/bcm63xx/clk.c:259:6: error: redefinition of 'clk_disable'
include/linux/clk.h:300:20: note: previous definition of 'clk_disable' was here
arch/mips/bcm63xx/clk.c:268:15: error: redefinition of 'clk_get_rate'
include/linux/clk.h:302:29: note: previous definition of 'clk_get_rate' was here
arch/mips/bcm63xx/clk.c:275:13: error: redefinition of 'clk_get'
include/linux/clk.h:281:27: note: previous definition of 'clk_get' was here
arch/mips/bcm63xx/clk.c:302:6: error: redefinition of 'clk_put'
include/linux/clk.h:291:20: note: previous definition of 'clk_put' was here
make[2]: *** [arch/mips/bcm63xx/clk.o] Error 1
Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips@linux-mips.org
Reviewed-by: John Crispin <blogic@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/4141/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ar7/clock.c:420:5: error: redefinition of 'clk_enable'
include/linux/clk.h:295:19: note: previous definition of 'clk_enable' was here
arch/mips/ar7/clock.c:426:6: error: redefinition of 'clk_disable'
include/linux/clk.h:300:20: note: previous definition of 'clk_disable' was here
arch/mips/ar7/clock.c:431:15: error: redefinition of 'clk_get_rate'
include/linux/clk.h:302:29: note: previous definition of 'clk_get_rate' was here
arch/mips/ar7/clock.c:437:13: error: redefinition of 'clk_get'
include/linux/clk.h:281:27: note: previous definition of 'clk_get' was here
arch/mips/ar7/clock.c:454:6: error: redefinition of 'clk_put'
include/linux/clk.h:291:20: note: previous definition of 'clk_put' was here
make[2]: *** [arch/mips/ar7/clock.o] Error 1
Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips@linux-mips.org
Reviewed-by: John Crispin <blogic@openwrt.org>
Acked-by: Florian Fainelli <florian@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/4140/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

As we use CLKDEV_LOOKUP but dont have support for COMMON_CLK yet, we need to
provide our own version of of_clk_get_from_provider().
Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4117/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Add a lantiq specific version of device_tree_init. The generic MIPS version
was removed by.

commit 594e966bc412d64eec9282d28ce511bdd62fea39
Author: David Daney <david.daney@cavium.com>
Date:   Thu Jul 5 18:12:38 2012 +0200

MIPS: Prune some target specific code out of prom.c
Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4116/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The XRX200 based SoC have a different register offset for the interface
clock and PCI control registers. This patch detects the SoC and sets the
register offset at runtime. This make PCI work on the VR9 SoC.
Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4113/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

* set_fs(KERNEL_DS) + getname() is probably the weirdest implementation
of strdup() I've seen.  Especially since they don't to copy it at all...
* filp_open() never returns NULL; it's ERR_PTR(-E...) on failure.
* file->f_dentry is never going to be NULL, TYVM.
* match_strdup() + snprintf() + kfree() is a bloody weird way to spell
match_strlcpy().

Pox on cargo-cult programmers...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Support the MD RAID10 personality through dm-raid.c
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Pull in pre-requisites for adding raid10 support to dm-raid.

__generic_unplug_device() function is removed with commit
7eaceacc, which forgot to
remove the declaration at meantime. Here remove it.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add a new operation code (BLKPG_RESIZE_PARTITION) to the BLKPG ioctl that
allows altering the size of an existing partition, even if it is currently
in use.

This patch converts hd_struct->nr_sects into sequence counter because
One might extend a partition while IO is happening to it and update of
nr_sects can be non-atomic on 32bit machines with 64bit sector_t. This
can lead to issues like reading inconsistent size of a partition. Sequence
counter have been used so that readers don't have to take bdev mutex lock
as we call sector_in_part() very frequently.

Now all the access to hd_struct->nr_sects should happen using sequence
counter read/update helper functions part_nr_sects_read/part_nr_sects_write.
There is one exception though, set_capacity()/get_capacity(). I think
theoritically race should exist there too but this patch does not
modify set_capacity()/get_capacity() due to sheer number of call sites
and I am afraid that change might break something. I have left that as a
TODO item. We can handle it later if need be. This patch does not introduce
any new races as such w.r.t set_capacity()/get_capacity().

v2: Add CONFIG_LBDAF test to UP preempt case as suggested by Phillip.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Phillip Susi <psusi@ubuntu.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Hi,

I'm using the old-fashioned 'dump' backup tool, and I noticed that it spews the
below warning as of 3.5-rc1 and later (3.4 is fine):

[   10.886893] ------------[ cut here ]------------
[   10.886904] WARNING: at include/linux/iocontext.h:140 copy_process+0x1488/0x1560()
[   10.886905] Hardware name: Bochs
[   10.886906] Modules linked in:
[   10.886908] Pid: 2430, comm: dump Not tainted 3.5.0-rc7+ #27
[   10.886908] Call Trace:
[   10.886911]  [<ffffffff8107ce8a>] warn_slowpath_common+0x7a/0xb0
[   10.886912]  [<ffffffff8107ced5>] warn_slowpath_null+0x15/0x20
[   10.886913]  [<ffffffff8107c088>] copy_process+0x1488/0x1560
[   10.886914]  [<ffffffff8107c244>] do_fork+0xb4/0x340
[   10.886918]  [<ffffffff8108effa>] ? recalc_sigpending+0x1a/0x50
[   10.886919]  [<ffffffff8108f6b2>] ? __set_task_blocked+0x32/0x80
[   10.886920]  [<ffffffff81091afa>] ? __set_current_blocked+0x3a/0x60
[   10.886923]  [<ffffffff81051db3>] sys_clone+0x23/0x30
[   10.886925]  [<ffffffff8179bd73>] stub_clone+0x13/0x20
[   10.886927]  [<ffffffff8179baa2>] ? system_call_fastpath+0x16/0x1b
[   10.886928] ---[ end trace 32a14af7ee6a590b ]---

Reproducing is easy, I can hit it on a KVM system with a very basic
config (x86_64 make defconfig + enable the drivers needed). To hit it,
just install dump (on debian/ubuntu, not sure what the package might be
called on Fedora), and:

dump -o -f /tmp/foo /

You'll see the warning in dmesg once it forks off the I/O process and
starts dumping filesystem contents.

I bisected it down to the following commit:

commit f6e8d01b
Author: Tejun Heo <tj@kernel.org>
Date:   Mon Mar 5 13:15:26 2012 -0800

    block: add io_context->active_ref

    Currently ioc->nr_tasks is used to decide two things - whether an ioc
    is done issuing IOs and whether it's shared by multiple tasks.  This
    patch separate out the first into ioc->active_ref, which is acquired
    and released using {get|put}_io_context_active() respectively.

    This will be used to associate bio's with a given task.  This patch
    doesn't introduce any visible behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
    Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

It seems like the init of ioc->nr_tasks was removed in that patch,
so it starts out at 0 instead of 1.

Tejun, is the right thing here to add back the init, or should something else
be done?

The below patch removes the warning, but I haven't done any more extensive
testing on it.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk_set_stacking_limits is intended to allow stacking drivers to build
up the limits of the stacked device based on the underlying devices'
limits.  But defaulting 'max_sectors' to BLK_DEF_MAX_SECTORS (1024)
doesn't allow the stacking driver to inherit a max_sectors larger than
1024 -- due to blk_stack_limits' use of min_not_zero.

It is now clear that this artificial limit is getting in the way so
change blk_set_stacking_limits's max_sectors to UINT_MAX (which allows
stacking drivers like dm-multipath to inherit 'max_sectors' from the
underlying paths).
Reported-by: Vijay Chauhan <vijay.chauhan@netapp.com>
Tested-by: Vijay Chauhan <vijay.chauhan@netapp.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

uac_clock_source_is_valid() uses the control selector value to access
the bmControls bitmap of the clock source unit. This is wrong, as
control selector values start from 1, while the bitmap uses all
available bits.

In other words, "Clock Validity Control" is stored in D3..2, not D5..4
of the clock selector unit's bmControls.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-by: Andreas Koch <andreas@akdesigninc.com>
Cc: stable@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>