memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails

If kthread_run() fails, pgdat->kswapd contains errno.  When we stop this
thread, we only check whether pgdat->kswapd is NULL and access it.  If
it contains errno, it will cause page fault.  Reset pgdat->kswapd to
NULL when creating kernel thread fails can avoid this problem.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/ia64: fix a memory block size bug

I found following definition in include/linux/memory.h, in my IA64
platform, SECTION_SIZE_BITS is equal to 32, and MIN_MEMORY_BLOCK_SIZE
will be 0.

  #define MIN_MEMORY_BLOCK_SIZE     (1 << SECTION_SIZE_BITS)

Because MIN_MEMORY_BLOCK_SIZE is int type and length of 32bits,
so MIN_MEMORY_BLOCK_SIZE(1 << 32) will will equal to 0.
Actually when SECTION_SIZE_BITS >= 31, MIN_MEMORY_BLOCK_SIZE will be wrong.
This will cause wrong system memory infomation in sysfs.
I think it should be:

  #define MIN_MEMORY_BLOCK_SIZE     (1UL << SECTION_SIZE_BITS)

And "echo offline > memory0/state" will cause following call trace:

  kernel BUG at mm/memory_hotplug.c:885!
  sh[6455]: bugcheck! 0 [1]
  Pid: 6455, CPU 0, comm:                   sh
  psr : 0000101008526030 ifs : 8000000000000fa4 ip  : [<a0000001008c40f0>]    Not tainted (3.6.0-rc1)
  ip is at offline_pages+0x210/0xee0
  Call Trace:
    show_stack+0x80/0xa0
    show_regs+0x640/0x920
    die+0x190/0x2c0
    die_if_kernel+0x50/0x80
    ia64_bad_break+0x3d0/0x6e0
    ia64_native_leave_kernel+0x0/0x270
    offline_pages+0x210/0xee0
    alloc_pages_current+0x180/0x2a0

Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MAINTAINERS: fix TXT maintainer list and source repo path

Signed-off-by: Gang Wei <gang.wei@intel.com>
Cc: Richard L Maliszewski <richard.l.maliszewski@intel.com>
Cc: Gang Wei <gang.wei@intel.com>
Cc: Shane Wang <shane.wang@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
nbd: clear waiting_queue on shutdown

Fix a serious but uncommon bug in nbd which occurs when there is heavy
I/O going to the nbd device while, at the same time, a failure (server,
network) or manual disconnect of the nbd connection occurs.

There is a small window between the time that the nbd_thread is stopped
and the socket is shutdown where requests can continue to be queued to
nbd's internal waiting_queue.  When this happens, those requests are
never completed or freed.

The fix is to clear the waiting_queue on shutdown of the nbd device, in
the same way that the nbd request queue (queue_head) is already being
cleared.

Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slab: do ClearSlabPfmemalloc() for all pages of slab

Right now, we call ClearSlabPfmemalloc() for first page of slab when we
clear SlabPfmemalloc flag.  This is fine for most swap-over-network use
cases as it is expected that order-0 pages are in use.  Unfortunately it
is possible that that __ac_put_obj() checks SlabPfmemalloc on a tail
page and while this is harmless, it is sloppy.  This patch ensures that
the head page is always used.

This problem was originally identified by Joonsoo Kim.

[js1304@gmail.com: Original implementation and problem identification]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slab: fix starting index for finding another object

In array cache, there is a object at index 0, check it.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slub: consider pfmemalloc_match() in get_partial_node()

get_partial() is currently not checking pfmemalloc_match() meaning that
it is possible for pfmemalloc pages to leak to non-pfmemalloc users.
This is a problem in the following situation.  Assume that there is a
request from normal allocation and there are no objects in the per-cpu
cache and no node-partial slab.

In this case, slab_alloc enters the slow path and new_slab_objects() is
called which may return a PFMEMALLOC page.  As the current user is not
allowed to access PFMEMALLOC page, deactivate_slab() is called
([5091b74a: mm: slub: optimise the SLUB fast path to avoid pfmemalloc
checks]) and returns an object from PFMEMALLOC page.

Next time, when we get another request from normal allocation,
slab_alloc() enters the slow-path and calls new_slab_objects().  In
new_slab_objects(), we call get_partial() and get a partial slab which
was just deactivated but is a pfmemalloc page.  We extract one object
from it and re-deactivate.

  "deactivate -> re-get in get_partial -> re-deactivate" occures repeatedly.

As a result, access to PFMEMALLOC page is not properly restricted and it
can cause a performance degradation due to frequent deactivation.
deactivation frequently.

This patch changes get_partial_node() to take pfmemalloc_match() into
account and prevents the "deactivate -> re-get in get_partial()
scenario.  Instead, new_slab() is called.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/net/sock.h: squelch compiler warning in sk_rmem_schedule()

This warning:

  In file included from linux/include/linux/tcp.h:227:0,
                   from linux/include/linux/ipv6.h:221,
                   from linux/include/net/ipv6.h:16,
                   from linux/include/linux/sunrpc/clnt.h:26,
                   from linux/net/sunrpc/stats.c:22:
  linux/include/net/sock.h: In function `sk_rmem_schedule':
  linux/nfs-2.6/include/net/sock.h:1339:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

is seen with gcc (GCC) 4.6.3 20120306 (Red Hat 4.6.3-2) using the
-Wextra option.

Commit c76562b6709f ("netvm: prevent a stream-specific deadlock")
accidentally replaced the "size" parameter of sk_rmem_schedule() with an
unsigned int.  This changes the semantics of the comparison in the
return statement.

In sk_wmem_schedule we have syntactically the same comparison, but
"size" is a signed integer.  In addition, __sk_mem_schedule() takes a
signed integer for its "size" parameter, so there is an implicit type
conversion in sk_rmem_schedule() anyway.

Revert the "size" parameter back to a signed integer so that the
semantics of the expressions in both sk_[rw]mem_schedule() are exactly
the same.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pid-namespace: limit value of ns_last_pid to (0, max_pid)

The kernel doesn't check the pid for negative values, so if you try to
write -2 to /proc/sys/kernel/ns_last_pid, you will get a kernel panic.

The crash happens because the next pid is -1, and alloc_pidmap() will
try to access to a nonexistent pidmap.

  map = &pid_ns->pidmap[pid/BITS_PER_PAGE];

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.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>
compiler.h: add __visible

gcc 4.6+ has support for a externally_visible attribute that prevents the
optimizer from optimizing unused symbols away.  Add a __visible macro to
use it with that compiler version or later.

This is used (at least) by the "Link Time Optimization" patchset.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/rtc-twl.c: ensure all interrupts are disabled during probe

On some platforms, bootloaders are known to do some interesting RTC
programming.  Without going into the obscurities as to why this may be
the case, suffice it to say the the driver should not make any
assumptions about the state of the RTC when the driver loads.  In
particular, the driver probe should be sure that all interrupts are
disabled until otherwise programmed.

This was discovered when finding bursty I2C traffic every second on
Overo platforms.  This I2C overhead was keeping the SoC from hitting
deep power states.  The cause was found to be the RTC firing every
second on the I2C-connected TWL PMIC.

Special thanks to Felipe Balbi for suggesting to look for a rogue driver
as the source of the I2C traffic rather than the I2C driver itself.

Special thanks to Steve Sakoman for helping track down the source of the
continuous RTC interrups on the Overo boards.

Signed-off-by: Kevin Hilman <khilman@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Tested-by: Steve Sakoman <steve@sakoman.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Tested-by: Shubhrajyoti Datta <omaplinuxkernel@gmail.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/page_alloc: fix the page address of higher page's buddy calculation

The heuristic method for buddy has been introduced since commit
43506fad21ca ("mm/page_alloc.c: simplify calculation of combined index
of adjacent buddy lists").  But the page address of higher page's buddy
was wrongly calculated, which will lead page_is_buddy to fail for ever.
IOW, the heuristic method would be disabled with the wrong page address
of higher page's buddy.

Calculating the page address of higher page's buddy should be based
higher_page with the offset between index of higher page and index of
higher page's buddy.

Signed-off-by: Haifeng Li <omycle@gmail.com>
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KyongHo Cho <pullip.cho@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: <stable@vger.kernel.org>	[2.6.38+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memory hotplug: fix section info double registration bug

There may be a bug when registering section info.  For example, on my
Itanium platform, the pfn range of node0 includes the other nodes, so
other nodes' section info will be double registered, and memmap's page
count will equal to 3.

  node0: start_pfn=0x100,    spanned_pfn=0x20fb00, present_pfn=0x7f8a3, => 0x000100-0x20fc00
  node1: start_pfn=0x80000,  spanned_pfn=0x80000,  present_pfn=0x80000, => 0x080000-0x100000
  node2: start_pfn=0x100000, spanned_pfn=0x80000,  present_pfn=0x80000, => 0x100000-0x180000
  node3: start_pfn=0x180000, spanned_pfn=0x80000,  present_pfn=0x80000, => 0x180000-0x200000

  free_all_bootmem_node()
	register_page_bootmem_info_node()
		register_page_bootmem_info_section()

When hot remove memory, we can't free the memmap's page because
page_count() is 2 after put_page_bootmem().

  sparse_remove_one_section()
	free_section_usemap()
		free_map_bootmem()
			put_page_bootmem()

[akpm@linux-foundation.org: add code comment]
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'akpm' (Andrew's patch-bomb)

Merge fixes from Andrew Morton:
 "13 patches.  12 are fixes and one is a little preparatory thing for
  Andi."

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (13 commits)
  memory hotplug: fix section info double registration bug
  mm/page_alloc: fix the page address of higher page's buddy calculation
  drivers/rtc/rtc-twl.c: ensure all interrupts are disabled during probe
  compiler.h: add __visible
  pid-namespace: limit value of ns_last_pid to (0, max_pid)
  include/net/sock.h: squelch compiler warning in sk_rmem_schedule()
  slub: consider pfmemalloc_match() in get_partial_node()
  slab: fix starting index for finding another object
  slab: do ClearSlabPfmemalloc() for all pages of slab
  nbd: clear waiting_queue on shutdown
  MAINTAINERS: fix TXT maintainer list and source repo path
  mm/ia64: fix a memory block size bug
  memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails