mm, oom: move declaration for mem_cgroup_out_of_memory to oom.h

mem_cgroup_out_of_memory() is defined in mm/oom_kill.c, so declare it in
linux/oom.h rather than linux/memcontrol.h.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hotplug: mark memory hotplug code in page_alloc.c as __meminit

Mark functions used by both boot and memory hotplug as __meminit to reduce
memory footprint when memory hotplug is disabled.

Alos guard zone_pcp_update() with CONFIG_MEMORY_HOTPLUG because it's only
used by memory hotplug code.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Wei Wang <Bessel.Wang@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hotplug: free zone->pageset when a zone becomes empty

When a zone becomes empty after memory offlining, free zone->pageset.
Otherwise it will cause memory leak when adding memory to the empty zone
again because build_all_zonelists() will allocate zone->pageset for an
empty zone.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Wei Wang <Bessel.Wang@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hotplug: correctly add new zone to all other nodes' zone lists

When online_pages() is called to add new memory to an empty zone, it
rebuilds all zone lists by calling build_all_zonelists().  But there's a
bug which prevents the new zone to be added to other nodes' zone lists.

online_pages() {
build_all_zonelists()
.....
node_set_state(zone_to_nid(zone), N_HIGH_MEMORY)
}

Here the node of the zone is put into N_HIGH_MEMORY state after calling
build_all_zonelists(), but build_all_zonelists() only adds zones from
nodes in N_HIGH_MEMORY state to the fallback zone lists.
build_all_zonelists()

    ->__build_all_zonelists()
->build_zonelists()
    ->find_next_best_node()
->for_each_node_state(n, N_HIGH_MEMORY)

So memory in the new zone will never be used by other nodes, and it may
cause strange behavor when system is under memory pressure.  So put node
into N_HIGH_MEMORY state before calling build_all_zonelists().

Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hotplug: correctly setup fallback zonelists when creating new pgdat

When hotadd_new_pgdat() is called to create new pgdat for a new node, a
fallback zonelist should be created for the new node.  There's code to try
to achieve that in hotadd_new_pgdat() as below:

/*
 * The node we allocated has no zone fallback lists. For avoiding
 * to access not-initialized zonelist, build here.
 */
mutex_lock(&zonelists_mutex);
build_all_zonelists(pgdat, NULL);
mutex_unlock(&zonelists_mutex);

But it doesn't work as expected.  When hotadd_new_pgdat() is called, the
new node is still in offline state because node_set_online(nid) hasn't
been called yet.  And build_all_zonelists() only builds zonelists for
online nodes as:

        for_each_online_node(nid) {
                pg_data_t *pgdat = NODE_DATA(nid);

                build_zonelists(pgdat);
                build_zonelist_cache(pgdat);
        }

Though we hope to create zonelist for the new pgdat, but it doesn't.  So
add a new parameter "pgdat" the build_all_zonelists() to build pgdat for
the new pgdat too.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcg: replace inexistence move_lock_page_cgroup() by move_lock_mem_cgroup() in comment

Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcg: mem_cgroup_relize_xxx_limit can guarantee memcg->res.limit <= memcg->memsw.limit

Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcg: complete documentation for tcp memcg files

Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: setup pageblock_order before it's used by sparsemem

On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as
Itanium, pageblock_order is a variable with default value of 0.  It's set
to the right value by set_pageblock_order() in function
free_area_init_core().

But pageblock_order may be used by sparse_init() before free_area_init_core()
is called along path:
sparse_init()
    ->sparse_early_usemaps_alloc_node()
->usemap_size()
    ->SECTION_BLOCKFLAGS_BITS
->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) *
NR_PAGEBLOCK_BITS)

The uninitialized pageblock_size will cause memory wasting because
usemap_size() returns a much bigger value then it's really needed.

For example, on an Itanium platform,
sparse_init() pageblock_order=0 usemap_size=24576
free_area_init_core() before pageblock_order=0, usemap_size=24576
free_area_init_core() after pageblock_order=12, usemap_size=8

That means 24K memory has been wasted for each section, so fix it by calling
set_pageblock_order() from sparse_init().

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c:print_vma_addr(): call up_read(&mm->mmap_sem) directly

Call up_read(&mm->mmap_sem) directly since we have already got mm via
current->mm at the beginning of print_vma_addr().

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

vmscan: remove obsolete shrink_control comment

09f363c7 ("vmscan: fix shrinker callback bug in fs/super.c") fixed a
shrinker callback which was returning -1 when nr_to_scan is zero, which
caused excessive slab scanning.  But 635697c6 ("vmscan: fix initial
shrinker size handling") fixed the problem, again so we can freely return
-1 although nr_to_scan is zero.  So let's revert 09f363c7 because the
comment added in 09f363c7 made an unnecessary rule.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: CONFIG_HAVE_MEMBLOCK_NODE -> CONFIG_HAVE_MEMBLOCK_NODE_MAP

0ee332c14518699 ("memblock: Kill early_node_map[]") wanted to replace
CONFIG_ARCH_POPULATES_NODE_MAP with CONFIG_HAVE_MEMBLOCK_NODE_MAP but
ended up replacing one occurence with a reference to the non-existent
symbol CONFIG_HAVE_MEMBLOCK_NODE.

The resulting omission of code would probably have been causing problems
to 32-bit machines with memory hotplug.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: have order > 0 compaction start off where it left

Order > 0 compaction stops when enough free pages of the correct page
order have been coalesced.  When doing subsequent higher order
allocations, it is possible for compaction to be invoked many times.

However, the compaction code always starts out looking for things to
compact at the start of the zone, and for free pages to compact things to
at the end of the zone.

This can cause quadratic behaviour, with isolate_freepages starting at the
end of the zone each time, even though previous invocations of the
compaction code already filled up all free memory on that end of the zone.

This can cause isolate_freepages to take enormous amounts of CPU with
certain workloads on larger memory systems.

The obvious solution is to have isolate_freepages remember where it left
off last time, and continue at that point the next time it gets invoked
for an order > 0 compaction.  This could cause compaction to fail if
cc->free_pfn and cc->migrate_pfn are close together initially, in that
case we restart from the end of the zone and try once more.

Forced full (order == -1) compactions are left alone.

[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: s/laste/last/, use 80 cols]
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Jim Schutt <jaschut@sandia.gov>
Tested-by: Jim Schutt <jaschut@sandia.gov>
Cc: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: rename mem_control_xxx to memcg_xxx

Replace memory_cgroup_xxx() with memcg_xxx()

Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: fix bad behavior in use_hierarchy file

I have an application that does the following:

* copy the state of all controllers attached to a hierarchy
* replicate it as a child of the current level.

I would expect writes to the files to mostly succeed, since they are
inheriting sane values from parents.

But that is not the case for use_hierarchy.  If it is set to 0, we succeed
ok.  If we're set to 1, the value of the file is automatically set to 1 in
the children, but if userspace tries to write the very same 1, it will
fail.  That same situation happens if we set use_hierarchy, create a
child, and then try to write 1 again.

Now, there is no reason whatsoever for failing to write a value that is
already there.  It doesn't even match the comments, that states:

 /* If parent's use_hierarchy is set, we can't make any modifications
  * in the child subtrees...

since we are not changing anything.

So test the new value against the one we're storing, and automatically
return 0 if we're not proposing a change.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Dhaval Giani <dhaval.giani@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove unused LRU_ALL_EVICTABLE

Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: rename config variables

Sanity:

CONFIG_CGROUP_MEM_RES_CTLR -> CONFIG_MEMCG
CONFIG_CGROUP_MEM_RES_CTLR_SWAP -> CONFIG_MEMCG_SWAP
CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED -> CONFIG_MEMCG_SWAP_ENABLED
CONFIG_CGROUP_MEM_RES_CTLR_KMEM -> CONFIG_MEMCG_KMEM

[mhocko@suse.cz: fix missed bits]
Cc: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: clean up __count_immobile_pages()

The __count_immobile_pages() naming is rather awkward.  Choose a more
clear name and add a comment.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: do not use page_count() without a page pin

d179e84ba ("mm: vmscan: do not use page_count without a page pin") fixed
this problem in vmscan.c but same problem is in __count_immobile_pages().

I copy and paste d179e84ba's contents for description.

"It is unsafe to run page_count during the physical pfn scan because
compound_head could trip on a dangling pointer when reading
page->first_page if the compound page is being freed by another CPU."

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wanpeng Li <liwp.linux@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: replace some information in tasklist dump

The number of ptes and swap entries are used in the oom killer's badness
heuristic, so they should be shown in the tasklist dump.

This patch adds those fields and replaces cpu and oom_adj values that are
currently emitted.  Cpu isn't interesting and oom_adj is deprecated and
will be removed later this year, the same information is already displayed
as oom_score_adj which is used internally.

At the same time, make the documentation a little more clear to state this
information is helpful to determine why the oom killer chose the task it
did to kill.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: fix potential killing of thread that is disabled from oom killing

/proc/sys/vm/oom_kill_allocating_task will immediately kill current when
the oom killer is called to avoid a potentially expensive tasklist scan
for large systems.

Currently, however, it is not checking current's oom_score_adj value which
may be OOM_SCORE_ADJ_MIN, meaning that it has been disabled from oom
killing.

This patch avoids killing current in such a condition and simply falls
back to the tasklist scan since memory still needs to be freed.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: clear pages_scanned only if draining a pcp adds pages to the buddy allocator again

commit 2ff754fa8f ("mm: clear pages_scanned only if draining a pcp adds
pages to the buddy allocator again") fixed one free_pcppages_bulk()
misuse.  But two another miuse still exist.

This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, fadvise: don't return -EINVAL when filesystem cannot implement fadvise()

Eric Wong reported his test suite failex when /tmp is tmpfs.

https://lkml.org/lkml/2012/2/24/479

Currentlt the input check of POSIX_FADV_WILLNEED has two problems.

- requires a_ops->readpage.  But in fact, force_page_cache_readahead()
  requires that the target filesystem has either ->readpage or ->readpages.

- returns -EINVAL when the filesystem doesn't have ->readpage.  But
  posix says that fadvise is merely a hint.  Thus fadvise() should return
  0 if filesystem has no means of implementing fadvise().  The userland
  application should not know nor care whcih type of filesystem backs the
  TMPDIR directory, as Eric pointed out.  There is nothing which userspace
  can do to solve this error.

So change the return value to 0 when filesytem doesn't support readahead.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Eric Wong <normalperson@yhbt.net>
Tested-by: Eric Wong <normalperson@yhbt.net>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/compaction: cleanup on compaction_deferred

When CONFIG_COMPACTION is enabled, compaction_deferred() tries to
recalculate the deferred limit again, which isn't necessary.

When CONFIG_COMPACTION is disabled, compaction_deferred() should return
"true" or "false" since it has "bool" for its return value.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: make mem_cgroup_force_empty_list() return bool

mem_cgroup_force_empty_list() just returns 0 or -EBUSY and -EBUSY
indicates 'you need to retry'.  Make mem_cgroup_force_empty_list() return
a bool to simplify the logic.

[akpm@linux-foundation.org: rework mem_cgroup_force_empty_list()'s comment]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: mem_cgroup_move_parent() doesn't need gfp_mask

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: clean up force_empty_list() return value check

After bf544fdc241da8 "memcg: move charges to root cgroup if
use_hierarchy=0 in mem_cgroup_move_hugetlb_parent()"
mem_cgroup_move_parent() returns only -EBUSY or -EINVAL.  So we can remove
the -ENOMEM and -EINTR checks.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: remove check for signal_pending() during rmdir()

After bf544fdc241da8 "memcg: move charges to root cgroup if
use_hierarchy=0 in mem_cgroup_move_hugetlb_parent()", no memory reclaim
will occur when removing a memory cgroup.  If -EINTR is returned here,
cgroup will show a warning.

We don't need to handle any user interruption signal.  Remove this.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memblock.c:memblock_double_array(): cosmetic cleanups

This function is an 80-column eyesore, quite unnecessarily.  Clean that
up, and use standard comment layout style.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Greg Pearson <greg.pearson@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: do not schedule if current has been killed

The oom killer currently schedules away from current in an uninterruptible
sleep if it does not have access to memory reserves.  It's possible that
current was killed because it shares memory with the oom killed thread or
because it was killed by the user in the interim, however.

This patch only schedules away from current if it does not have a pending
kill, i.e.  if it does not share memory with the oom killed thread.  It's
possible that it will immediately retry its memory allocation and fail,
but it will immediately be given access to memory reserves if it calls the
oom killer again.

This prevents the delay of memory freeing when threads that share memory
with the oom killed thread get unnecessarily scheduled.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: remove exclude and wakeup rmdir calls from migrate

We already hold the hugetlb_lock.  That should prevent a parallel cgroup
rmdir from touching page's hugetlb cgroup.  So remove the exclude and
wakeup calls.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: assign the page hugetlb cgroup when we move the page to active list.

A page's hugetlb cgroup assignment and movement to the active list should
occur with hugetlb_lock held.  Otherwise when we remove the hugetlb cgroup
we will iterate the active list and find pages with NULL hugetlb cgroup
values.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: move all the in use pages to active list

When we fail to allocate pages from the reserve pool, hugetlb tries to
allocate huge pages using alloc_buddy_huge_page.  Add these to the active
list.  We also need to add the huge page we allocate when we soft offline
the oldpage to active list.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: add HugeTLB controller documentation

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: migrate hugetlb cgroup info from oldpage to new page during migration

With HugeTLB pages, hugetlb cgroup is uncharged in compound page
destructor.  Since we are holding a hugepage reference, we can be sure
that old page won't get uncharged till the last put_page().

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: add hugetlb cgroup control files

Add the control files for hugetlb controller

[akpm@linux-foundation.org: s/CONFIG_CGROUP_HUGETLB_RES_CTLR/CONFIG_MEMCG_HUGETLB/g]
[akpm@linux-foundation.org: s/CONFIG_MEMCG_HUGETLB/CONFIG_CGROUP_HUGETLB/]
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: add support for cgroup removal

Add support for cgroup removal.  If we don't have parent cgroup, the
charges are moved to root cgroup.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: add charge/uncharge routines for hugetlb cgroup

Add the charge and uncharge routines for hugetlb cgroup.  We do cgroup
charging in page alloc and uncharge in compound page destructor.
Assigning page's hugetlb cgroup is protected by hugetlb_lock.

[liwp@linux.vnet.ibm.com: add huge_page_order check to avoid incorrect uncharge]
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb/cgroup: add the cgroup pointer to page lru

Add the hugetlb cgroup pointer to 3rd page lru.next.  This limit the usage
to hugetlb cgroup to only hugepages with 3 or more normal pages.  I guess
that is an acceptable limitation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb: add new HugeTLB cgroup

Implement a new controller that allows us to control HugeTLB allocations.
The extension allows to limit the HugeTLB usage per control group and
enforces the controller limit during page fault.  Since HugeTLB doesn't
support page reclaim, enforcing the limit at page fault time implies that,
the application will get SIGBUS signal if it tries to access HugeTLB pages
beyond its limit.  This requires the application to know beforehand how
much HugeTLB pages it would require for its use.

The charge/uncharge calls will be added to HugeTLB code in later patch.
Support for cgroup removal will be added in later patches.

[akpm@linux-foundation.org: s/CONFIG_CGROUP_HUGETLB_RES_CTLR/CONFIG_MEMCG_HUGETLB/g]
[akpm@linux-foundation.org: s/CONFIG_MEMCG_HUGETLB/CONFIG_CGROUP_HUGETLB/g]
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: make some static variables global

We will use them later in hugetlb_cgroup.c

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: add a list for tracking in-use HugeTLB pages

hugepage_activelist will be used to track currently used HugeTLB pages.
We need to find the in-use HugeTLB pages to support HugeTLB cgroup removal.
On cgroup removal we update the page's HugeTLB cgroup to point to parent
cgroup.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: simplify migrate_huge_page()

Since we migrate only one hugepage, don't use linked list for passing the
page around.  Directly pass the page that need to be migrated as argument.
This also removes the usage of page->lru in the migrate path.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages

Use a mmu_gather instead of a temporary linked list for accumulating pages
when we unmap a hugepage range

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: add an inline helper for finding hstate index

Add an inline helper and use it in the code.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: don't use ERR_PTR with VM_FAULT* values

The current use of VM_FAULT_* codes with ERR_PTR requires us to ensure
VM_FAULT_* values will not exceed MAX_ERRNO value.  Decouple the
VM_FAULT_* values from MAX_ERRNO.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlb: rename max_hstate to hugetlb_max_hstate

This patchset implements a cgroup resource controller for HugeTLB pages.
The controller allows to limit the HugeTLB usage per control group and
enforces the controller limit during page fault.  Since HugeTLB doesn't
support page reclaim, enforcing the limit at page fault time implies that,
the application will get SIGBUS signal if it tries to access HugeTLB pages
beyond its limit.  This requires the application to know beforehand how
much HugeTLB pages it would require for its use.

The goal is to control how many HugeTLB pages a group of task can
allocate.  It can be looked at as an extension of the existing quota
interface which limits the number of HugeTLB pages per hugetlbfs
superblock.  HPC job scheduler requires jobs to specify their resource
requirements in the job file.  Once their requirements can be met, job
schedulers like (SLURM) will schedule the job.  We need to make sure that
the jobs won't consume more resources than requested.  If they do we
should either error out or kill the application.

This patch:

Rename max_hstate to hugetlb_max_hstate.  We will be using this from other
subsystems like hugetlb controller in later patches.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: prepare for removal of obsolete /proc/sys/vm/nr_pdflush_threads

Since per-BDI flusher threads were introduced in 2.6, the pdflush
mechanism is not used any more.  But the old interface exported through
/proc/sys/vm/nr_pdflush_threads still exists and is obviously useless.

For back-compatibility, printk warning information and return 2 to notify
the users that the interface is removed.

Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/buddy: cleanup on should_fail_alloc_page

Currently, function should_fail() has "bool" for its return value, so it's
reasonable to change the return value of function should_fail_alloc_page()
into "bool" as well.

The patch does cleanup on function should_fail_alloc_page() to have "bool"
for its return value.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: account the total_vm in the vm_stat_account()

vm_stat_account() accounts the shared_vm, stack_vm and reserved_vm now.
But we can also account for total_vm in the vm_stat_account() which makes
the code tidy.

Even for mprotect_fixup(), we can get the right result in the end.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

documentation: update how page-cluster affects swap I/O

Fix of the documentation of /proc/sys/vm/page-cluster to match the
behavior of the code and add some comments about what the tunable will
change in that behavior.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

swap: allow swap readahead to be merged

Swap readahead works fine, but the I/O to disk is almost always done in
page size requests, despite the fact that readahead submits
1<<page-cluster pages at a time.

On older kernels the old per device plugging behavior might have captured
this and merged the requests, but currently all comes down to much more
I/Os than required.

On a single device this might not be an issue, but as soon as a server
runs on shared san resources savin I/Os not only improves swapin
throughput but also provides a lower resource utilization.

With a load running KVM in a lot of memory overcommitment (the hot memory
is 1.5 times the host memory) swapping throughput improves significantly
and the lead feels more responsive as well as achieves more throughput.

In a test setup with 16 swap disks running blocktrace on one of those disks
shows the improved merging:
Prior:
Reads Queued:     560,888,    2,243MiB  Writes Queued:     226,242,  904,968KiB
Read Dispatches:  544,701,    2,243MiB  Write Dispatches:  159,318,  904,968KiB
Reads Requeued:         0               Writes Requeued:         0
Reads Completed:  544,716,    2,243MiB  Writes Completed:  159,321,  904,980KiB
Read Merges:       16,187,   64,748KiB  Write Merges:       61,744,  246,976KiB
IO unplugs:       149,614               Timer unplugs:       2,940

With the patch:
Reads Queued:     734,315,    2,937MiB  Writes Queued:     300,188,    1,200MiB
Read Dispatches:  214,972,    2,937MiB  Write Dispatches:  215,176,    1,200MiB
Reads Requeued:         0               Writes Requeued:         0
Reads Completed:  214,971,    2,937MiB  Writes Completed:  215,177,    1,200MiB
Read Merges:      519,343,    2,077MiB  Write Merges:       73,325,  293,300KiB
IO unplugs:       337,130               Timer unplugs:      11,184

I got ~10% to ~40% more throughput in my cases and at the same time much
lower cpu consumption when broken down per transferred kilobyte (the
majority of that due to saved interrupts and better cache handling).  In a
shared SAN others might get an additional benefit as well, because this
now causes less protocol overhead.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: remove MEM_CGROUP_CHARGE_TYPE_FORCE

There are no users since commit b24028572fb69 ("memcg: remove PCG_CACHE").

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: rename MEM_CGROUP_CHARGE_TYPE_MAPPED as MEM_CGROUP_CHARGE_TYPE_ANON

Now, in memcg, 2 "MAPPED" enum/macro are found
 MEM_CGROUP_CHARGE_TYPE_MAPPED
 MEM_CGROUP_STAT_FILE_MAPPED

Thier names looks similar to each other but the former is used for
accounting anonymous memory. rename it as TYPE_ANON.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: rename MEM_CGROUP_STAT_SWAPOUT as MEM_CGROUP_STAT_SWAP

MEM_CGROUP_STAT_SWAPOUT represents the usage of swap rather than
the number of swap-out events. Rename it to be MEM_CGROUP_STAT_SWAP.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: make vb_alloc() more foolproof

If someone calls vb_alloc() (or vm_map_ram() for that matter) to allocate
0 bytes (0 pages), get_order() returns BITS_PER_LONG - PAGE_CACHE_SHIFT
and interesting stuff happens.  So make debugging such problems easier and
warn about 0-size allocation.

[akpm@linux-foundation.org: use WARN_ON-return-value feature]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

vmalloc: walk vmap_areas by sorted list instead of rb_next()

There's a walk by repeating rb_next to find a suitable hole.  Could be
simply replaced by walk on the sorted vmap_area_list.  More simpler and
efficient.

Mutation of the list and tree only happens in pair within
__insert_vmap_area and __free_vmap_area, under protection of
vmap_area_lock.  The patch code is also under vmap_area_lock, so the list
walk is safe, and consistent with the tree walk.

Tested on SMP by repeating batch of vmalloc anf vfree for random sizes and
rounds for hours.

Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/media/video/v4l2-ioctl.c: fix build

Fix zillions of these:

drivers/media/video/v4l2-ioctl.c:1848: error: unknown field 'func' specified in initializer
drivers/media/video/v4l2-ioctl.c:1848: warning: missing braces around initializer
drivers/media/video/v4l2-ioctl.c:1848: warning: (near initialization for 'v4l2_ioctls[0].<anonymous>')
drivers/media/video/v4l2-ioctl.c:1848: warning: initialization makes integer from pointer without a cast
drivers/media/video/v4l2-ioctl.c:1848: error: initializer element is not computable at load time
drivers/media/video/v4l2-ioctl.c:1848: error: (near initialization for 'v4l2_ioctls[0].<anonymous>.offset')

Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

xtensa: select generic atomic64_t support

This will fix build errors:

block/blk-cgroup.c:609:2: error: unknown type name 'atomic64_t'
block/blk-cgroup.c:609:2: error: implicit declaration of function 'ATOMIC64_INIT' [-Werror=implicit-function-declaration]

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fault-injection: fix failcmd.sh warning

"fault-injection: add tool to run command with failslab or
fail_page_alloc" added tools/testing/fault-injection/failcmd.sh to make it
easier to inject slab/page allocation failures by fault injection.

failcmd.sh prints the following warning when running with arguments
for command.

# ./failcmd.sh echo aaa
failcmd.sh: line 209: [: echo: binary operator expected
aaa

This warning is caused by an improper check whether at least one
parameter is left after parsing command options.

Fix it by testing the length of $1 instead of $@

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'writeback-proportions' of git://git./linux/kernel/git/wfg/linux

Pull writeback updates from Wu Fengguang:
 "Use time based periods to age the writeback proportions, which can
  adapt equally well to fast/slow devices."

Fix up trivial conflict in comment in fs/sync.c

* tag 'writeback-proportions' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: Fix some comment errors
  block: Convert BDI proportion calculations to flexible proportions
  lib: Fix possible deadlock in flexible proportion code
  lib: Proportions with flexible period

Merge tag 'nfs-for-3.6-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Features include:
   - More preparatory patches for modularising NFSv2/v3/v4.  Split out
     the various NFSv2/v3/v4-specific code into separate files
   - More preparation for the NFSv4 migration code
   - Ensure that OPEN(O_CREATE) observes the pNFS mds threshold
     parameters
   - pNFS fast failover when the data servers are down
   - Various cleanups and debugging patches"

* tag 'nfs-for-3.6-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (67 commits)
  nfs: fix fl_type tests in NFSv4 code
  NFS: fix pnfs regression with directio writes
  NFS: fix pnfs regression with directio reads
  sunrpc: clnt: Add missing braces
  nfs: fix stub return type warnings
  NFS: exit_nfs_v4() shouldn't be an __exit function
  SUNRPC: Add a missing spin_unlock to gss_mech_list_pseudoflavors
  NFS: Split out NFS v4 client functions
  NFS: Split out the NFS v4 filesystem types
  NFS: Create a single nfs_clone_super() function
  NFS: Split out NFS v4 server creating code
  NFS: Initialize the NFS v4 client from init_nfs_v4()
  NFS: Move the v4 getroot code to nfs4getroot.c
  NFS: Split out NFS v4 file operations
  NFS: Initialize v4 sysctls from nfs_init_v4()
  NFS: Create an init_nfs_v4() function
  NFS: Split out NFS v4 inode operations
  NFS: Split out NFS v3 inode operations
  NFS: Split out NFS v2 inode operations
  NFS: Clean up nfs4_proc_setclientid() and friends
  ...

Merge tag 'mfd-for-linus-3.6-1' of git://git./linux/kernel/git/sameo/mfd-2.6

Pull MFD fix from Samuel Ortiz:
 "This one fixes an s5m8767 regulator build breakage due to a merge
  conflict caused by the MFD s5m API changes."

* tag 'mfd-for-linus-3.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6:
  regulator: Fix an s5m8767 build failure

Merge branch 'v4l_for_linus' of git://git./linux/kernel/git/mchehab/linux-media

Pull media updates from Mauro Carvalho Chehab:
 "This is the first part of the media patches for v3.6.

  This patch series contain:
   - new DVB frontend: rtl2832
   - new video drivers: adv7393
   - some unused files got removed
   - a selection API cleanup between V4L2 and V4L2 subdev API's
   - a major redesign at v4l-ioctl2, in order to clean it up
   - several driver fixes and improvements."

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (174 commits)
  v4l: Export v4l2-common.h in include/linux/Kbuild
  media: Revert "[media] Terratec Cinergy S2 USB HD Rev.2"
  [media] media: Use pr_info not homegrown pr_reg macro
  [media] Terratec Cinergy S2 USB HD Rev.2
  [media] v4l: Correct conflicting V4L2 subdev selection API documentation
  [media] Feature removal: V4L2 selections API target and flag definitions
  [media] v4l: Unify selection flags documentation
  [media] v4l: Unify selection flags
  [media] v4l: Common documentation for selection targets
  [media] v4l: Unify selection targets across V4L2 and V4L2 subdev interfaces
  [media] v4l: Remove "_ACTUAL" from subdev selection API target definition names
  [media] V4L: Remove "_ACTIVE" from the selection target name definitions
  [media] media: dvb-usb: print mac address via native %pM
  [media] s5p-tv: Use module_i2c_driver in sii9234_drv.c file
  [media] media: gpio-ir-recv: add allowed_protos for platform data
  [media] s5p-jpeg: Use module_platform_driver in jpeg-core.c file
  [media] saa7134: fix spelling of detach in label
  [media] cx88-blackbird: replace ioctl by unlocked_ioctl
  [media] cx88: don't use current_norm
  [media] cx88: fix a number of v4l2-compliance violations
  ...

Merge branch 'akpm' (Andrew's patch-bomb)

Merge Andrew's first set of patches:
 "Non-MM patches:

   - lots of misc bits

   - tree-wide have_clk() cleanups

   - quite a lot of printk tweaks.  I draw your attention to "printk:
     convert the format for KERN_<LEVEL> to a 2 byte pattern" which
     looks a bit scary.  But afaict it's solid.

   - backlight updates

   - lib/ feature work (notably the addition and use of memweight())

   - checkpatch updates

   - rtc updates

   - nilfs updates

   - fatfs updates (partial, still waiting for acks)

   - kdump, proc, fork, IPC, sysctl, taskstats, pps, etc

   - new fault-injection feature work"

* Merge emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits)
  drivers/misc/lkdtm.c: fix missing allocation failure check
  lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table()
  fault-injection: add tool to run command with failslab or fail_page_alloc
  fault-injection: add selftests for cpu and memory hotplug
  powerpc: pSeries reconfig notifier error injection module
  memory: memory notifier error injection module
  PM: PM notifier error injection module
  cpu: rewrite cpu-notifier-error-inject module
  fault-injection: notifier error injection
  c/r: fcntl: add F_GETOWNER_UIDS option
  resource: make sure requested range is included in the root range
  include/linux/aio.h: cpp->C conversions
  fs: cachefiles: add support for large files in filesystem caching
  pps: return PTR_ERR on error in device_create
  taskstats: check nla_reserve() return
  sysctl: suppress kmemleak messages
  ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION
  ipc: compat: use signed size_t types for msgsnd and msgrcv
  ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPC
  ipc: add COMPAT_SHMLBA support
  ...

drivers/misc/lkdtm.c: fix missing allocation failure check

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=44691

Reported-by: <rucsoftsec@gmail.com>
Signed-off-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>

lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table()

We are seeing a lot of sg_alloc_table allocation failures using the new
drm prime infrastructure.  We isolated the cause to code in
__sg_alloc_table that was re-writing the gfp_flags.

There is a comment in the code that suggest that there is an assumption
about the allocation coming from a memory pool.  This was likely true
when sg lists were primarily used for disk I/O.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <rob.clark@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fault-injection: add tool to run command with failslab or fail_page_alloc

This adds tools/testing/fault-injection/failcmd.sh to run a command while
injecting slab/page allocation failures via fault injection.

Example:

Run a command "make -C tools/testing/selftests/ run_tests" with
injecting slab allocation failure.

# ./tools/testing/fault-injection/failcmd.sh \
-- make -C tools/testing/selftests/ run_tests

Same as above except to specify 100 times failures at most instead of
one time at most by default.

# ./tools/testing/fault-injection/failcmd.sh --times=100 \
-- make -C tools/testing/selftests/ run_tests

Same as above except to inject page allocation failure instead of slab
allocation failure.

# env FAILCMD_TYPE=fail_page_alloc \
./tools/testing/fault-injection/failcmd.sh --times=100 \
-- make -C tools/testing/selftests/ run_tests

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fault-injection: add selftests for cpu and memory hotplug

This adds two selftests

* tools/testing/selftests/cpu-hotplug/on-off-test.sh is testing script
for CPU hotplug

1. Online all hot-pluggable CPUs
2. Offline all hot-pluggable CPUs
3. Online all hot-pluggable CPUs again
4. Exit if cpu-notifier-error-inject.ko is not available
5. Offline all hot-pluggable CPUs in preparation for testing
6. Test CPU hot-add error handling by injecting notifier errors
7. Online all hot-pluggable CPUs in preparation for testing
8. Test CPU hot-remove error handling by injecting notifier errors

* tools/testing/selftests/memory-hotplug/on-off-test.sh is doing the
similar thing for memory hotplug.

1. Online all hot-pluggable memory
2. Offline 10% of hot-pluggable memory
3. Online all hot-pluggable memory again
4. Exit if memory-notifier-error-inject.ko is not available
5. Offline 10% of hot-pluggable memory in preparation for testing
6. Test memory hot-add error handling by injecting notifier errors
7. Online all hot-pluggable memory in preparation for testing
8. Test memory hot-remove error handling by injecting notifier errors

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

powerpc: pSeries reconfig notifier error injection module

This provides the ability to inject artifical errors to pSeries reconfig
notifier chain callbacks.  It is controlled through debugfs interface
under /sys/kernel/debug/notifier-error-inject/pSeries-reconfig

If the notifier call chain should be failed with some events
notified, write the error code to "actions/<notifier event>/error".

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memory: memory notifier error injection module

This provides the ability to inject artifical errors to memory hotplug
notifier chain callbacks.  It is controlled through debugfs interface
under /sys/kernel/debug/notifier-error-inject/memory

If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".

Example: Inject memory hotplug offline error (-12 == -ENOMEM)

# cd /sys/kernel/debug/notifier-error-inject/memory
# echo -12 > actions/MEM_GOING_OFFLINE/error
# echo offline > /sys/devices/system/memory/memoryXXX/state
bash: echo: write error: Cannot allocate memory

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PM: PM notifier error injection module

This provides the ability to inject artifical errors to PM notifier chain
callbacks.  It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/pm

Each of the files in "error" directory represents an event which can be
failed and contains the error code.  If the notifier call chain should be
failed with some events notified, write the error code to the files.

If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".

Example: Inject PM suspend error (-12 = -ENOMEM)

# cd /sys/kernel/debug/notifier-error-inject/pm
# echo -12 > actions/PM_SUSPEND_PREPARE/error
# echo mem > /sys/power/state
bash: echo: write error: Cannot allocate memory

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

cpu: rewrite cpu-notifier-error-inject module

Rewrite existing cpu-notifier-error-inject module to use debugfs based new
framework.

This change removes cpu_up_prepare_error and cpu_down_prepare_error module
parameters which were used to specify error code to be injected.  We could
keep these module parameters for backward compatibility by module_param_cb
but it seems overkill for this module.

This provides the ability to inject artifical errors to CPU notifier chain
callbacks.  It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/cpu

If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".

Example1: inject CPU offline error (-1 == -EPERM)

# cd /sys/kernel/debug/notifier-error-inject/cpu
# echo -1 > actions/CPU_DOWN_PREPARE/error
# echo 0 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Operation not permitted

Example2: inject CPU online error (-2 == -ENOENT)

# cd /sys/kernel/debug/notifier-error-inject/cpu
# echo -2 > actions/CPU_UP_PREPARE/error
# echo 1 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: No such file or directory

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fault-injection: notifier error injection

This patchset provides kernel modules that can be used to test the error
handling of notifier call chain failures by injecting artifical errors to
the following notifier chain callbacks.

 * CPU notifier
 * PM notifier
 * memory hotplug notifier
 * powerpc pSeries reconfig notifier

Example: Inject CPU offline error (-1 == -EPERM)

  # cd /sys/kernel/debug/notifier-error-inject/cpu
  # echo -1 > actions/CPU_DOWN_PREPARE/error
  # echo 0 > /sys/devices/system/cpu/cpu1/online
  bash: echo: write error: Operation not permitted

The patchset also adds cpu and memory hotplug tests to
tools/testing/selftests These tests first do simple online and offline
test and then do fault injection tests if notifier error injection
module is available.

This patch:

The notifier error injection provides the ability to inject artifical
errors to specified notifier chain callbacks.  It is useful to test the
error handling of notifier call chain failures.

This adds common basic functions to define which type of events can be
fail and to initialize the debugfs interface to control what error code
should be returned and which event should be failed.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

c/r: fcntl: add F_GETOWNER_UIDS option

When we restore file descriptors we would like them to look exactly as
they were at dumping time.

With help of fcntl it's almost possible, the missing snippet is file
owners UIDs.

To be able to read their values the F_GETOWNER_UIDS is introduced.

This option is valid iif CONFIG_CHECKPOINT_RESTORE is turned on, otherwise
returning -EINVAL.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

resource: make sure requested range is included in the root range

When the requested range is outside of the root range the logic in
__reserve_region_with_split will cause an infinite recursion which will
overflow the stack as seen in the warning bellow.

This particular stack overflow was caused by requesting the
(100000000-107ffffff) range while the root range was (0-ffffffff).  In
this case __request_resource would return the whole root range as
conflict range (i.e.  0-ffffffff).  Then, the logic in
__reserve_region_with_split would continue the recursion requesting the
new range as (conflict->end+1, end) which incidentally in this case
equals the originally requested range.

This patch aborts looking for an usable range when the request does not
intersect with the root range.  When the request partially overlaps with
the root range, it ajust the request to fall in the root range and then
continues with the new request.

When the request is modified or aborted errors and a stack trace are
logged to allow catching the errors in the upper layers.

[    5.968374] WARNING: at kernel/sched.c:4129 sub_preempt_count+0x63/0x89()
[    5.975150] Modules linked in:
[    5.978184] Pid: 1, comm: swapper Not tainted 3.0.22-mid27-00004-gb72c817 #46
[    5.985324] Call Trace:
[    5.987759]  [<c1039dfc>] ? console_unlock+0x17b/0x18d
[    5.992891]  [<c1039620>] warn_slowpath_common+0x48/0x5d
[    5.998194]  [<c1031758>] ? sub_preempt_count+0x63/0x89
[    6.003412]  [<c1039644>] warn_slowpath_null+0xf/0x13
[    6.008453]  [<c1031758>] sub_preempt_count+0x63/0x89
[    6.013499]  [<c14d60c4>] _raw_spin_unlock+0x27/0x3f
[    6.018453]  [<c10c6349>] add_partial+0x36/0x3b
[    6.022973]  [<c10c7c0a>] deactivate_slab+0x96/0xb4
[    6.027842]  [<c14cf9d9>] __slab_alloc.isra.54.constprop.63+0x204/0x241
[    6.034456]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.039842]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.045232]  [<c10c7dc9>] kmem_cache_alloc_trace+0x51/0xb0
[    6.050710]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.056100]  [<c103f78f>] kzalloc.constprop.5+0x29/0x38
[    6.061320]  [<c17b45e9>] __reserve_region_with_split+0x1c/0xd1
[    6.067230]  [<c17b4693>] __reserve_region_with_split+0xc6/0xd1
...
[    7.179057]  [<c17b4693>] __reserve_region_with_split+0xc6/0xd1
[    7.184970]  [<c17b4779>] reserve_region_with_split+0x30/0x42
[    7.190709]  [<c17a8ebf>] e820_reserve_resources_late+0xd1/0xe9
[    7.196623]  [<c17c9526>] pcibios_resource_survey+0x23/0x2a
[    7.202184]  [<c17cad8a>] pcibios_init+0x23/0x35
[    7.206789]  [<c17ca574>] pci_subsys_init+0x3f/0x44
[    7.211659]  [<c1002088>] do_one_initcall+0x72/0x122
[    7.216615]  [<c17ca535>] ? pci_legacy_init+0x3d/0x3d
[    7.221659]  [<c17a27ff>] kernel_init+0xa6/0x118
[    7.226265]  [<c17a2759>] ? start_kernel+0x334/0x334
[    7.231223]  [<c14d7482>] kernel_thread_helper+0x6/0x10

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/aio.h: cpp->C conversions

Convert init_sync_kiocb() from a nasty macro into a nice C function.  The
struct assignment trick takes care of zeroing all unmentioned fields.
Shrinks fs/read_write.o's .text from 9857 bytes to 9714.

Also demacroize is_sync_kiocb() and aio_ring_avail().  The latter fixes an
arg-referenced-multiple-times hand grenade.

Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: cachefiles: add support for large files in filesystem caching

Support the caching of large files.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=31182

Signed-off-by: Justin Lecher <jlec@gentoo.org>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.com>
Tested-by: Suresh Jayaraman <sjayaraman@suse.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

pps: return PTR_ERR on error in device_create

We should return PTR_ERR if the call to the device_create function fails.
Without this patch we instead return the value from a successful call to
cdev_add if the call to device_create fails.

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Acked-by: Devendra Naga <devendra.aaru@gmail.com>
Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: check nla_reserve() return

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=44621

Reported-by: <rucsoftsec@gmail.com>
Signed-off-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>

sysctl: suppress kmemleak messages

register_sysctl_table() is a strange function, as it makes internal
allocations (a header) to register a sysctl_table.  This header is a
handle to the table that is created, and can be used to unregister the
table.  But if the table is permanent and never unregistered, the header
acts the same as a static variable.

Unfortunately, this allocation of memory that is never expected to be
freed fools kmemleak in thinking that we have leaked memory.  For those
sysctl tables that are never unregistered, and have no pointer referencing
them, kmemleak will think that these are memory leaks:

unreferenced object 0xffff880079fb9d40 (size 192):
  comm "swapper/0", pid 0, jiffies 4294667316 (age 12614.152s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8146b590>] kmemleak_alloc+0x73/0x98
    [<ffffffff8110a935>] kmemleak_alloc_recursive.constprop.42+0x16/0x18
    [<ffffffff8110b852>] __kmalloc+0x107/0x153
    [<ffffffff8116fa72>] kzalloc.constprop.8+0xe/0x10
    [<ffffffff811703c9>] __register_sysctl_paths+0xe1/0x160
    [<ffffffff81170463>] register_sysctl_paths+0x1b/0x1d
    [<ffffffff8117047d>] register_sysctl_table+0x18/0x1a
    [<ffffffff81afb0a1>] sysctl_init+0x10/0x14
    [<ffffffff81b05a6f>] proc_sys_init+0x2f/0x31
    [<ffffffff81b0584c>] proc_root_init+0xa5/0xa7
    [<ffffffff81ae5b7e>] start_kernel+0x3d0/0x40a
    [<ffffffff81ae52a7>] x86_64_start_reservations+0xae/0xb2
    [<ffffffff81ae53ad>] x86_64_start_kernel+0x102/0x111
    [<ffffffffffffffff>] 0xffffffffffffffff

The sysctl_base_table used by sysctl itself is one such instance that
registers the table to never be unregistered.

Use kmemleak_not_leak() to suppress the kmemleak false positive.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION

Rather than #define the options manually in the architecture code, add
Kconfig options for them and select them there instead.  This also allows
us to select the compat IPC version parsing automatically for platforms
using the old compat IPC interface.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc: compat: use signed size_t types for msgsnd and msgrcv

The msgsnd and msgrcv system calls use size_t to represent the size of the
message being transferred.  POSIX states that values of msgsz greater than
SSIZE_MAX cause the result to be implementation-defined.  On Linux, this
equates to returning -EINVAL if (long) msgsz < 0.

For compat tasks where !CONFIG_ARCH_WANT_OLD_COMPAT_IPC and compat_size_t
is smaller than size_t, negative size values passed from userspace will be
interpreted as positive values by do_msg{rcv,snd} and will fail to exit
early with -EINVAL.

This patch changes the compat prototypes for msg{rcv,snd} so that the
message size is represented as a compat_ssize_t, which we cast to the
native ssize_t type for the core IPC code.

Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPC

Commit 48b25c43e6ee ("ipc: provide generic compat versions of IPC
syscalls") added a new ARCH_WANT_OLD_COMPAT_IPC config option for
architectures to select if their compat target requires the old IPC
syscall interface.

For architectures (such as AArch64) that do not require the internal
calling conventions provided by this option, but have a compat target
where the C library passes the IPC_64 flag explicitly,
compat_ipc_parse_version no longer strips out the flag before calling
the native system call implementation, resulting in unknown SHM/IPC
commands and -EINVAL being returned to userspace.

This patch separates the selection of the internal calling conventions
for the IPC syscalls from the version parsing, allowing architectures to
select __ARCH_WANT_COMPAT_IPC_PARSE_VERSION if they want to use version
parsing whilst retaining the newer syscall calling conventions.

Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc: add COMPAT_SHMLBA support

If the SHMLBA definition for a native task differs from the definition for
a compat task, the do_shmat() function would need to handle both.

This patch introduces COMPAT_SHMLBA, which is used by the compat shmat
syscall when calling the ipc code and allows architectures such as AArch64
(where the native SHMLBA is 64k but the compat (AArch32) definition is
16k) to provide the correct semantics for compat IPC system calls.

Cc: David S. Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kdump: append newline to the last lien of vmcoreinfo note

The last line of vmcoreinfo note does not end with \n.  Parsing all the
lines in note becomes easier if all lines end with \n instead of trying to
special case the last line.

I know at least one tool, vmcore-dmesg in kexec-tools tree which made the
assumption that all lines end with \n.  I think it is a good idea to fix
it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fork: fix error handling in dup_task()

The function dup_task() may fail at the following function calls in the
following order.

0) alloc_task_struct_node()
1) alloc_thread_info_node()
2) arch_dup_task_struct()

Error by 0) is not a matter, it can just return.  But error by 1) requires
releasing task_struct allocated by 0) before it returns.  Likewise, error
by 2) requires releasing task_struct and thread_info allocated by 0) and
1).

The existing error handling calls free_task_struct() and
free_thread_info() which do not only release task_struct and thread_info,
but also call architecture specific arch_release_task_struct() and
arch_release_thread_info().

The problem is that task_struct and thread_info are not fully initialized
yet at this point, but arch_release_task_struct() and
arch_release_thread_info() are called with them.

For example, x86 defines its own arch_release_task_struct() that releases
a task_xstate.  If alloc_thread_info_node() fails in dup_task(),
arch_release_task_struct() is called with task_struct which is just
allocated and filled with garbage in this error handling.

This actually happened with tools/testing/fault-injection/failcmd.sh

# env FAILCMD_TYPE=fail_page_alloc \
./tools/testing/fault-injection/failcmd.sh --times=100 \
--min-order=0 --ignore-gfp-wait=0 \
-- make -C tools/testing/selftests/ run_tests

In order to fix this issue, make free_{task_struct,thread_info}() not to
call arch_release_{task_struct,thread_info}() and call
arch_release_{task_struct,thread_info}() implicitly where needed.

Default arch_release_task_struct() and arch_release_thread_info() are
defined as empty by default.  So this change only affects the
architectures which implement their own arch_release_task_struct() or
arch_release_thread_info() as listed below.

arch_release_task_struct(): x86, sh
arch_release_thread_info(): mn10300, tile

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Salman Qazi <sqazi@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

revert "sched: Fix fork() error path to not crash"

To make way for "fork: fix error handling in dup_task()", which fixes the
errors more completely.

Cc: Salman Qazi <sqazi@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fork: use vma_pages() to simplify the code

The current code can be replaced by vma_pages().  So use it to simplify
the code.

[akpm@linux-foundation.org: initialise `len' at its definition site]
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: do not allow negative offsets on /proc/<pid>/environ

__mem_open() which is called by both /proc/<pid>/environ and
/proc/<pid>/mem ->open() handlers will allow the use of negative offsets.
/proc/<pid>/mem has negative offsets but not /proc/<pid>/environ.

Clean this by moving the 'force FMODE_UNSIGNED_OFFSET flag' to mem_open()
to allow negative offsets only on /proc/<pid>/mem.

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Brad Spengler <spender@grsecurity.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: environ_read() make sure offset points to environment address range

Currently the following offset and environment address range check in
environ_read() of /proc/<pid>/environ is buggy:

  int this_len = mm->env_end - (mm->env_start + src);
  if (this_len <= 0)
    break;

Large or negative offsets on /proc/<pid>/environ converted to 'unsigned
long' may pass this check since '(mm->env_start + src)' can overflow and
'this_len' will be positive.

This can turn /proc/<pid>/environ to act like /proc/<pid>/mem since
(mm->env_start + src) will point and read from another VMA.

There are two fixes here plus some code cleaning:

1) Fix the overflow by checking if the offset that was converted to
   unsigned long will always point to the [mm->env_start, mm->env_end]
   address range.

2) Remove the truncation that was made to the result of the check,
   storing the result in 'int this_len' will alter its value and we can
   not depend on it.

For kernels that have commit b409e578d ("proc: clean up
/proc/<pid>/environ handling") which adds the appropriate ptrace check and
saves the 'mm' at ->open() time, this is not a security issue.

This patch is taken from the grsecurity patch since it was just made
available.

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Brad Spengler <spender@grsecurity.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

coredump: fix wrong comments on core limits of pipe coredump case

In commit 898b374af6f7 ("exec: replace call_usermodehelper_pipe with use
of umh init function and resolve limit"), the core limits recursive
check value was changed from 0 to 1, but the corresponding comments were
not updated.

Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kmod: avoid deadlock from recursive kmod call

The system deadlocks (at least since 2.6.10) when
call_usermodehelper(UMH_WAIT_EXEC) request triggers
call_usermodehelper(UMH_WAIT_PROC) request.

This is because "khelper thread is waiting for the worker thread at
wait_for_completion() in do_fork() since the worker thread was created
with CLONE_VFORK flag" and "the worker thread cannot call complete()
because do_execve() is blocked at UMH_WAIT_PROC request" and "the khelper
thread cannot start processing UMH_WAIT_PROC request because the khelper
thread is waiting for the worker thread at wait_for_completion() in
do_fork()".

The easiest example to observe this deadlock is to use a corrupted
/sbin/hotplug binary (like shown below).

  # : > /tmp/dummy
  # chmod 755 /tmp/dummy
  # echo /tmp/dummy > /proc/sys/kernel/hotplug
  # modprobe whatever

call_usermodehelper("/tmp/dummy", UMH_WAIT_EXEC) is called from
kobject_uevent_env() in lib/kobject_uevent.c upon loading/unloading a
module.  do_execve("/tmp/dummy") triggers a call to
request_module("binfmt-0000") from search_binary_handler() which in turn
calls call_usermodehelper(UMH_WAIT_PROC).

In order to avoid deadlock, as a for-now and easy-to-backport solution, do
not try to call wait_for_completion() in call_usermodehelper_exec() if the
worker thread was created by khelper thread with CLONE_VFORK flag.  Future
and fundamental solution might be replacing singleton khelper thread with
some workqueue so that recursive calls up to max_active dependency loop
can be handled without deadlock.

[akpm@linux-foundation.org: add comment to kmod_thread_locker]
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/kmod.c: document call_usermodehelper_fns() a bit

This function's interface is, uh, subtle.  Attempt to apologise for it.

Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fat: refactor shortname parsing

Nearly identical shortname parsing is performed in fat_search_long() and
__fat_readdir().  Extract this code into a function that may be called by
both.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fat: accessors for msdos_dir_entry 'start' fields

Simplify code by providing accessor functions for the directory entry
start cluster fields.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hfsplus: use -ENOMEM when kzalloc() fails

Use -ENOMEM return value instead of -EINVAL when kzalloc() fails.

Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add omitted comments for different structures in driver implementation

Add omitted comments for different structures in driver implementation.

Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add omitted comments for structures in nilfs2_fs.h

Add omitted comments for structures in nilfs2_fs.h.

Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix deadlock issue between chcp and thaw ioctls

An fs-thaw ioctl causes deadlock with a chcp or mkcp -s command:

 chcp            D ffff88013870f3d0     0  1325   1324 0x00000004
 ...
 Call Trace:
   nilfs_transaction_begin+0x11c/0x1a0 [nilfs2]
   wake_up_bit+0x20/0x20
   copy_from_user+0x18/0x30 [nilfs2]
   nilfs_ioctl_change_cpmode+0x7d/0xcf [nilfs2]
   nilfs_ioctl+0x252/0x61a [nilfs2]
   do_page_fault+0x311/0x34c
   get_unmapped_area+0x132/0x14e
   do_vfs_ioctl+0x44b/0x490
   __set_task_blocked+0x5a/0x61
   vm_mmap_pgoff+0x76/0x87
   __set_current_blocked+0x30/0x4a
   sys_ioctl+0x4b/0x6f
   system_call_fastpath+0x16/0x1b
 thaw            D ffff88013870d890     0  1352   1351 0x00000004
 ...
 Call Trace:
   rwsem_down_failed_common+0xdb/0x10f
   call_rwsem_down_write_failed+0x13/0x20
   down_write+0x25/0x27
   thaw_super+0x13/0x9e
   do_vfs_ioctl+0x1f5/0x490
   vm_mmap_pgoff+0x76/0x87
   sys_ioctl+0x4b/0x6f
   filp_close+0x64/0x6c
   system_call_fastpath+0x16/0x1b

where the thaw ioctl deadlocked at thaw_super() when called while chcp was
waiting at nilfs_transaction_begin() called from
nilfs_ioctl_change_cpmode().  This deadlock is 100% reproducible.

This is because nilfs_ioctl_change_cpmode() first locks sb->s_umount in
read mode and then waits for unfreezing in nilfs_transaction_begin(),
whereas thaw_super() locks sb->s_umount in write mode.  The locking of
sb->s_umount here was intended to make snapshot mounts and the downgrade
of snapshots to checkpoints exclusive.

This fixes the deadlock issue by replacing the sb->s_umount usage in
nilfs_ioctl_change_cpmode() with a dedicated mutex which protects snapshot
mounts.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>