There is a subtle bug when calculating a number of acquired objects.

Currently, we calculate "available = page->objects - page->inuse",
after acquire_slab() is called in get_partial_node().

In acquire_slab() with mode = 1, we always set new.inuse = page->objects.
So,

	acquire_slab(s, n, page, object == NULL);

	if (!object) {
		c->page = page;
		stat(s, ALLOC_FROM_PARTIAL);
		object = t;
		available = page->objects - page->inuse;

		!!! availabe is always 0 !!!
	...

Therfore, "available > s->cpu_partial / 2" is always false and
we always go to second iteration.
This patch correct this problem.

After that, we don't need return value of put_cpu_partial().
So remove it.
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

After we create a boot cache, we may allocate from it until it is bootstraped.
This will move the page from the partial list to the cpu slab list. If this
happens, the loop:

	list_for_each_entry(p, &n->partial, lru)

that we use to scan for all partial pages will yield nothing, and the pages
will keep pointing to the boot cpu cache, which is of course, invalid. To do
that, we should flush the cache to make sure that the cpu slab is back to the
partial list.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Reported-by: Steffen Michalke <StMichalke@web.de>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

commit "slab: Common Kmalloc cache determination" made mistake
in kmalloc_slab(). SLAB_CACHE_DMA is for kmem_cache creation,
not for allocation. For allocation, we should use GFP_XXX to identify
type of allocation. So, change SLAB_CACHE_DMA to GFP_DMA.
Acked-by: Christoph Lameter <cl@linux.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Variables were not properly converted and the conversion caused
a naming conflict.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

James Hogan hit boot problems in next-20130204 on Meta:

  META213-Thread0 DSP [LogF] kobject (4fc03980): tried to init an initialized object, something is seriously wrong.
  META213-Thread0 DSP [LogF]
  META213-Thread0 DSP [LogF] Call trace:
  META213-Thread0 DSP [LogF] [<4000888c>] _show_stack+0x68/0x7c
  META213-Thread0 DSP [LogF] [<400088b4>] _dump_stack+0x14/0x28
  META213-Thread0 DSP [LogF] [<40103794>] _kobject_init+0x58/0x9c
  META213-Thread0 DSP [LogF] [<40103810>] _kobject_create+0x38/0x64
  META213-Thread0 DSP [LogF] [<40103eac>] _kobject_create_and_add+0x14/0x8c
  META213-Thread0 DSP [LogF] [<40190ac4>] _mnt_init+0xd8/0x220
  META213-Thread0 DSP [LogF] [<40190508>] _vfs_caches_init+0xb0/0x160
  META213-Thread0 DSP [LogF] [<401851f4>] _start_kernel+0x274/0x340
  META213-Thread0 DSP [LogF] [<40188424>] _metag_start_kernel+0x58/0x6c
  META213-Thread0 DSP [LogF] [<40000044>] __start+0x44/0x48
  META213-Thread0 DSP [LogF]
  META213-Thread0 DSP [LogF] devtmpfs: initialized
  META213-Thread0 DSP [LogF] L2 Cache: Not present
  META213-Thread0 DSP [LogF] BUG: failure at fs/sysfs/dir.c:736/sysfs_read_ns_type()!
  META213-Thread0 DSP [LogF] Kernel panic - not syncing: BUG!
  META213-Thread0 DSP [Thread Exit] Thread has exited - return code = 4294967295

And bisected the problem to commit 95a05b42 ("slab: Common constants for
kmalloc boundaries").

As it turns out, a fixed KMALLOC_SHIFT_LOW does not work for arches with
higher alignment requirements.

Determine KMALLOC_SHIFT_LOW from ARCH_DMA_MINALIGN instead.
Reported-and-tested-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Put the definitions for the kmem_cache_node structures together so that
we have one structure. That will allow us to create more common fields in
the future which could yield more opportunities to share code.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

The list3 or l3 pointers are pointing to per node structures. Reflect
that in the names of variables used.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Extract the optimized lookup functions from slub and put them into
slab_common.c. Then make slab use these functions as well.

Joonsoo notes that this fixes some issues with constant folding which
also reduces the code size for slub.

https://lkml.org/lkml/2012/10/20/82Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

On some platforms (such as IA64) the large page size may results in
slab allocations to be allowed of numbers that do not fit in 32 bit.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

The kmalloc array is created in similar ways in both SLAB
and SLUB. Create a common function and have both allocators
call that function.

V1->V2:
	Whitespace cleanup
Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Have a common definition fo the kmalloc cache arrays in
SLAB and SLUB
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Standardize the constants that describe the smallest and largest
object kept in the kmalloc arrays for SLAB and SLUB.

Differentiate between the maximum size for which a slab cache is used
(KMALLOC_MAX_CACHE_SIZE) and the maximum allocatable size
(KMALLOC_MAX_SIZE, KMALLOC_MAX_ORDER).
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Have a common naming between both slab caches for future changes.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Rename the structure used for the per node structures in slab
to have a name that expresses that fact.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Make slab use the common functions. We can get rid of a lot
of old ugly stuff as a results. Among them the sizes
array and the weird include/linux/kmalloc_sizes file and
some pretty bad #include statements in slab_def.h.

The one thing that is different in slab is that the 32 byte
cache will also be created for arches that have page sizes
larger than 4K. There are numerous smaller allocations that
SLOB and SLUB can handle better because of their support for
smaller allocation sizes so lets keep the 32 byte slab also
for arches with > 4K pages.
Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Extract the function to determine the index of the slab within
the array of kmalloc caches as well as a function to determine
maximum object size from the nr of the kmalloc slab.

This is used here only to simplify slub bootstrap but will
be used later also for SLAB.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Move these functions higher up in slab.h so that they are grouped with other
generic kmalloc related definitions.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

Pull watchdog updates from Wim Van Sebroeck:
 "This includes some fixes and code improvements (like
  clk_prepare_enable and clk_disable_unprepare), conversion from the
  omap_wdt and twl4030_wdt drivers to the watchdog framework, addition
  of the SB8x0 chipset support and the DA9055 Watchdog driver and some
  OF support for the davinci_wdt driver."

* git://www.linux-watchdog.org/linux-watchdog: (22 commits)
  watchdog: mei: avoid oops in watchdog unregister code path
  watchdog: Orion: Fix possible null-deference in orion_wdt_probe
  watchdog: sp5100_tco: Add SB8x0 chipset support
  watchdog: davinci_wdt: add OF support
  watchdog: da9052: Fix invalid free of devm_ allocated data
  watchdog: twl4030_wdt: Change TWL4030_MODULE_PM_RECEIVER to TWL_MODULE_PM_RECEIVER
  watchdog: remove depends on CONFIG_EXPERIMENTAL
  watchdog: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
  watchdog: DA9055 Watchdog driver
  watchdog: omap_wdt: eliminate goto
  watchdog: omap_wdt: delete redundant platform_set_drvdata() calls
  watchdog: omap_wdt: convert to devm_ functions
  watchdog: omap_wdt: convert to new watchdog core
  watchdog: WatchDog Timer Driver Core: fix comment
  watchdog: s3c2410_wdt: use clk_prepare_enable and clk_disable_unprepare
  watchdog: imx2_wdt: Select the driver via ARCH_MXC
  watchdog: cpu5wdt.c: add missing del_timer call
  watchdog: hpwdt.c: Increase version string
  watchdog: Convert twl4030_wdt to watchdog core
  davinci_wdt: preparation for switch to common clock framework
  ...

Pull CIFS fixes from Steve French:
 "Misc small cifs fixes"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: eliminate cifsERROR variable
  cifs: don't compare uniqueids in cifs_prime_dcache unless server inode numbers are in use
  cifs: fix double-free of "string" in cifs_parse_mount_options

Pull dm update from Alasdair G Kergon:
 "Miscellaneous device-mapper fixes, cleanups and performance
  improvements.

  Of particular note:
   - Disable broken WRITE SAME support in all targets except linear and
     striped.  Use it when kcopyd is zeroing blocks.
   - Remove several mempools from targets by moving the data into the
     bio's new front_pad area(which dm calls 'per_bio_data').
   - Fix a race in thin provisioning if discards are misused.
   - Prevent userspace from interfering with the ioctl parameters and
     use kmalloc for the data buffer if it's small instead of vmalloc.
   - Throttle some annoying error messages when I/O fails."

* tag 'dm-3.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm: (36 commits)
  dm stripe: add WRITE SAME support
  dm: remove map_info
  dm snapshot: do not use map_context
  dm thin: dont use map_context
  dm raid1: dont use map_context
  dm flakey: dont use map_context
  dm raid1: rename read_record to bio_record
  dm: move target request nr to dm_target_io
  dm snapshot: use per_bio_data
  dm verity: use per_bio_data
  dm raid1: use per_bio_data
  dm: introduce per_bio_data
  dm kcopyd: add WRITE SAME support to dm_kcopyd_zero
  dm linear: add WRITE SAME support
  dm: add WRITE SAME support
  dm: prepare to support WRITE SAME
  dm ioctl: use kmalloc if possible
  dm ioctl: remove PF_MEMALLOC
  dm persistent data: improve improve space map block alloc failure message
  dm thin: use DMERR_LIMIT for errors
  ...

This reverts commit 79f77bf9.

This is obviously wrong, and I have no idea how I missed seeing the
warning in testing: I must just not have looked at the right logs.  The
caller bumps rq_resused/rq_next_page, so it will always be hit on a
large enough read.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull more infiniband changes from Roland Dreier:
 "Second batch of InfiniBand/RDMA changes for 3.8:
   - cxgb4 changes to fix lookup engine hash collisions
   - mlx4 changes to make flow steering usable
   - fix to IPoIB to avoid pinning dst reference for too long"

* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  RDMA/cxgb4: Fix bug for active and passive LE hash collision path
  RDMA/cxgb4: Fix LE hash collision bug for passive open connection
  RDMA/cxgb4: Fix LE hash collision bug for active open connection
  mlx4_core: Allow choosing flow steering mode
  mlx4_core: Adjustments to Flow Steering activation logic for SR-IOV
  mlx4_core: Fix error flow in the flow steering wrapper
  mlx4_core: Add QPN enforcement for flow steering rules set by VFs
  cxgb4: Add LE hash collision bug fix path in LLD driver
  cxgb4: Add T4 filter support
  IPoIB: Call skb_dst_drop() once skb is enqueued for sending

Pull asm-generic cleanup from Arnd Bergmann:
 "These are a few cleanups for asm-generic:

   - a set of patches from Lars-Peter Clausen to generalize asm/mmu.h
     and use it in the architectures that don't need any special
     handling.
   - A patch from Will Deacon to remove the {read,write}s{b,w,l} as
     discussed during the arm64 review
   - A patch from James Hogan that helps with the meta architecture
     series."

* tag 'asm-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  xtensa: Use generic asm/mmu.h for nommu
  h8300: Use generic asm/mmu.h
  c6x: Use generic asm/mmu.h
  asm-generic/mmu.h: Add support for FDPIC
  asm-generic/mmu.h: Remove unused vmlist field from mm_context_t
  asm-generic: io: remove {read,write} string functions
  asm-generic/io.h: remove asm/cacheflush.h include

Commit db5b0ae0 ("Merge tag 'dt' of git://git.kernel.org/.../arm-soc")
causes a duplicated build target.  This patch fixes it and sorts out the
build target alphabetically so that we can recognize something wrong
easily.

Cc: Olof Johansson <olof@lixom.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Rename stripe_map_discard to stripe_map_range and reuse it for WRITE
SAME bio processing.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

This patch removes map_info from bio-based device mapper targets.
map_info is still used for request-based targets.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Eliminate struct map_info from dm-snap.

map_info->ptr was used in dm-snap to indicate if the bio was tracked.
If map_info->ptr was non-NULL, the bio was linked in tracked_chunk_hash.

This patch removes the use of map_info->ptr. We determine if the bio was
tracked based on hlist_unhashed(&c->node). If hlist_unhashed is true,
the bio is not tracked, if it is false, the bio is tracked.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

This patch removes endio_hook_pool from dm-thin and uses per-bio data instead.

This patch removes any use of map_info in preparation for the next patch
that removes map_info from bio-based device mapper.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Don't use map_info any more in dm-raid1.

map_info was used for writes to hold the region number. For this purpose
we add a new field dm_bio_details to dm_raid1_bio_record.

map_info was used for reads to hold a pointer to dm_raid1_bio_record (if
the pointer was non-NULL, bio details were saved; if the pointer was
NULL, bio details were not saved). We use
dm_raid1_bio_record.details->bi_bdev for this purpose. If bi_bdev is
NULL, details were not saved, if bi_bdev is non-NULL, details were
saved.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Replace map_info with a per-bio structure "struct per_bio_data" in dm-flakey.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Rename struct read_record to bio_record in dm-raid1.

In the following patch, the structure will be used for both read and
write bios, so rename it.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

This patch moves target_request_nr from map_info to dm_target_io and
makes it accessible with dm_bio_get_target_request_nr.

This patch is a preparation for the next patch that removes map_info.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Replace tracked_chunk_pool with per_bio_data in dm-snap.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Replace io_mempool with per_bio_data in dm-verity.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Replace read_record_pool with per_bio_data in dm-raid1.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Introduce a field per_bio_data_size in struct dm_target.

Targets can set this field in the constructor. If a target sets this
field to a non-zero value, "per_bio_data_size" bytes of auxiliary data
are allocated for each bio submitted to the target. These data can be
used for any purpose by the target and help us improve performance by
removing some per-target mempools.

Per-bio data is accessed with dm_per_bio_data. The
argument data_size must be the same as the value per_bio_data_size in
dm_target.

If the target has a pointer to per_bio_data, it can get a pointer to
the bio with dm_bio_from_per_bio_data() function (data_size must be the
same as the value passed to dm_per_bio_data).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Add WRITE SAME support to dm-io and make it accessible to
dm_kcopyd_zero().  dm_kcopyd_zero() provides an asynchronous interface
whereas the blkdev_issue_write_same() interface is synchronous.

WRITE SAME is a SCSI command that can be leveraged for more efficient
zeroing of a specified logical extent of a device which supports it.
Only a single zeroed logical block is transfered to the target for each
WRITE SAME and the target then writes that same block across the
specified extent.

The dm thin target uses this.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

The linear target can already support WRITE SAME requests so signal
this by setting num_write_same_requests to 1.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>