Pull UBIFS free space fix-up bugfix from Artem Bityutskiy:
 "It's been reported already twice recently:

    http://lists.infradead.org/pipermail/linux-mtd/2012-May/041408.html
    http://lists.infradead.org/pipermail/linux-mtd/2012-June/042422.html

  and we finally have the fix.  I am quite confident the fix is correct
  because I could reproduce the problem with nandsim and verify the fix.
  It was also verified by Iwo (the reporter).

  I am also confident that this is OK to merge the fix so late because
  this patch affects only the fixup functionality, which is not used by
  most users."

* tag 'upstream-3.5-rc8' of git://git.infradead.org/linux-ubifs:
  UBIFS: fix a bug in empty space fix-up

UBIFS has a feature called "empty space fix-up" which is a quirk to work-around
limitations of dumb flasher programs. Namely, of those flashers that are unable
to skip NAND pages full of 0xFFs while flashing, resulting in empty space at
the end of half-filled eraseblocks to be unusable for UBIFS. This feature is
relatively new (introduced in v3.0).

The fix-up routine (fixup_free_space()) is executed only once at the very first
mount if the superblock has the 'space_fixup' flag set (can be done with -F
option of mkfs.ubifs). It basically reads all the UBIFS data and metadata and
writes it back to the same LEB. The routine assumes the image is pristine and
does not have anything in the journal.

There was a bug in 'fixup_free_space()' where it fixed up the log incorrectly.
All but one LEB of the log of a pristine file-system are empty. And one
contains just a commit start node. And 'fixup_free_space()' just unmapped this
LEB, which resulted in wiping the commit start node. As a result, some users
were unable to mount the file-system next time with the following symptom:

UBIFS error (pid 1): replay_log_leb: first log node at LEB 3:0 is not CS node
UBIFS error (pid 1): replay_log_leb: log error detected while replaying the log at LEB 3:0

The root-cause of this bug was that 'fixup_free_space()' wrongly assumed
that the beginning of empty space in the log head (c->lhead_offs) was known
on mount. However, it is not the case - it was always 0. UBIFS does not store
in it the master node and finds out by scanning the log on every mount.

The fix is simple - just pass commit start node size instead of 0 to
'fixup_leb()'.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Cc: stable@vger.kernel.org [v3.0+]
Reported-by: Iwo Mergler <Iwo.Mergler@netcommwireless.com>
Tested-by: Iwo Mergler <Iwo.Mergler@netcommwireless.com>
Reported-by: James Nute <newten82@gmail.com>

Pull last minute Ceph fixes from Sage Weil:
 "The important one fixes a bug in the socket failure handling behavior
  that was turned up in some recent failure injection testing.  The
  other two are minor bug fixes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: endian bug in rbd_req_cb()
  rbd: Fix ceph_snap_context size calculation
  libceph: fix messenger retry

Pull three md bugfixes from NeilBrown:
 "One of the bugs was introduced in 3.5-rc1.  Others have been there for
  longer."

* tag 'md-3.5-fixes' of git://neil.brown.name/md:
  md/raid1: close some possible races on write errors during resync
  md: avoid crash when stopping md array races with closing other open fds.
  md: fix bug in handling of new_data_offset

Pull networking changes from David Miller:
 "Ok, we should be good to go now"

1) We have to statically initialize the init_net device list head rather
   than do so in an initcall, otherwise netprio_cgroup crashes if it's
   built statically rather than modular (Mark D.  Rustad)

2) Fix SKB null oopser in CIPSO ipv4 option processing (Paul Moore)

3) Qlogic maintainers update (Anirban Chakraborty)

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  net: Statically initialize init_net.dev_base_head
  MAINTAINERS: Changes in qlcnic and qlge maintainers list
  cipso: don't follow a NULL pointer when setsockopt() is called

Pull HID update from Jiri Kosina:
 "A final round of changes for HID for 3.5: just device ID additions."

* 'upstream-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: hid-multitouch: add support for Zytronic panels
  HID: add Sennheiser BTD500USB device support
  HID: add battery quirk for Apple Wireless ANSI

The strcpy was being used to set the name of the board.  Since the
destination char* was read-only and the name is set statically at
compile time; this was both wrong and redundant.

The type of char* is changed to const char* to prevent future errors.
Reported-by: Radek Masin <radek@masin.eu>
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
[ Taking directly due to vacations   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

commit 4367af55
   md/raid1: clear bad-block record when write succeeds.

Added a 'reschedule_retry' call possibility at the end of
end_sync_write, but didn't add matching code at the end of
sync_request_write.  So if the writes complete very quickly, or
scheduling makes it seem that way, then we can miss rescheduling
the request and the resync could hang.

Also commit 73d5c38a
    md: avoid races when stopping resync.

Fix a race condition in this same code in end_sync_write but didn't
make the change in sync_request_write.

This patch updates sync_request_write to fix both of those.
Patch is suitable for 3.1 and later kernels.
Reported-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Original-version-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

md will refuse to stop an array if any other fd (or mounted fs) is
using it.
When any fs is unmounted of when the last open fd is closed all
pending IO will be flushed (e.g. sync_blockdev call in __blkdev_put)
so there will be no pending IO to worry about when the array is
stopped.

However in order to send the STOP_ARRAY ioctl to stop the array one
must first get and open fd on the block device.
If some fd is being used to write to the block device and it is closed
after mdadm open the block device, but before mdadm issues the
STOP_ARRAY ioctl, then there will be no last-close on the md device so
__blkdev_put will not call sync_blockdev.

If this happens, then IO can still be in-flight while md tears down
the array and bad things can happen (use-after-free and subsequent
havoc).

So in the case where do_md_stop is being called from an open file
descriptor, call sync_block after taking the mutex to ensure there
will be no new openers.

This is needed when setting a read-write device to read-only too.

Cc: stable@vger.kernel.org
Reported-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

commit c6563a8c
    md: add possibility to change data-offset for devices.

introduced a 'new_data_offset' attribute which should normally
be the same as 'data_offset', but can be explicitly set to a different
value to allow a reshape operation to move the data.

Unfortunately when the 'data_offset' is explicitly set through
sysfs, the new_data_offset is not also set, so the two would become
out-of-sync incorrectly.

One result of this is that trying to set the 'size' after the
'data_offset' would fail because it is not permitted to set the size
when the 'data_offset' and 'new_data_offset' are different - as that
can be confusing.
Consequently when mdadm tried to do this while assembling an IMSM
array it would fail.

This bug was introduced in 3.5-rc1.
Reported-by: Brian Downing <bdowning@lavos.net>
Bisected-by: Brian Downing <bdowning@lavos.net>
Tested-by: Brian Downing <bdowning@lavos.net>
Signed-off-by: NeilBrown <neilb@suse.de>

Pull target fixes from Nicholas Bellinger:
 "This includes a bugfix from MDR to address a NULL pointer OOPs with
  FCoE aborts, along with a WRITE_SAME emulation bugfix for NOLB=0
  cases, and persistent reservation return cleanups from Roland.

  All three patches are CC'ed to stable."

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: Fix range calculation in WRITE SAME emulation when num blocks == 0
  target: Clean up returning errors in PR handling code
  tcm_fc: Fix crash seen with aborts and large reads

The referenced html file does not exist anymore. Replace the URL with
the current project homepage.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 37778088 ("bug.h: need linux/kernel.h for TAINT_WARN.") broke
all MIPS builds:

    CC      arch/mips/kernel/machine_kexec.o
  include/linux/log2.h: In function '__ilog2_u32':
  include/linux/log2.h:34:2: error: implicit declaration of function 'fls' [-Werror=implicit-function-declaration]
  include/linux/log2.h: In function '__ilog2_u64':
  include/linux/log2.h:42:2: error: implicit declaration of function 'fls64' [-Werror=implicit-function-declaration]
  ...
Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Tested-by: John Crispin <blogic@openwrt.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit a7a20d10 ("sd: limit the scope of the async probe domain")
make the SCSI device probing run device discovery in it's own async
domain.

However, as a result, the partition detection was no longer synchronized
by async_synchronize_full() (which, despite the name, only synchronizes
the global async space, not all of them).  Which in turn meant that
"wait_for_device_probe()" would not wait for the SCSI partitions to be
parsed.

And "wait_for_device_probe()" was what the boot time init code relied on
for mounting the root filesystem.

Now, most people never noticed this, because not only is it
timing-dependent, but modern distributions all use initrd.  So the root
filesystem isn't actually on a disk at all.  And then before they
actually mount the final disk filesystem, they will have loaded the
scsi-wait-scan module, which not only does the expected
wait_for_device_probe(), but also does scsi_complete_async_scans().

[ Side note: scsi_complete_async_scans() had also been partially broken,
  but that was fixed in commit 43a8d39d ("fix async probe
  regression"), so that same commit a7a20d10 had actually broken
  setups even if you used scsi-wait-scan explicitly ]

Solve this problem by just moving the scsi_complete_async_scans() call
into wait_for_device_probe().  Everybody who wants to wait for device
probing to finish really wants the SCSI probing to complete, so there's
no reason not to do this.

So now "wait_for_device_probe()" really does what the name implies, and
properly waits for device probing to finish.  This also removes the now
unnecessary extra calls to scsi_complete_async_scans().
Reported-and-tested-by: Artem S. Tashkinov <t.artem@mailcity.com>
Cc: Dan Williams <dan.j.williams@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: linux-scsi <linux-scsi@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull SELinux regression fixes from James Morris.

Andrew Morton has a box that hit that open perms problem.

I also renamed the "epollwakeup" selinux name for the new capability to
be "block_suspend", to match the rename done by commit d9914cf6
("PM: Rename CAP_EPOLLWAKEUP to CAP_BLOCK_SUSPEND").

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  SELinux: do not check open perms if they are not known to policy
  SELinux: include definition of new capabilities

This change eliminates an initialization-order hazard most
recently seen when netprio_cgroup is built into the kernel.

With thanks to Eric Dumazet for catching a bug.
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

One more time/ntp fix pulled from Ingo Molnar.

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ntp: Fix STA_INS/DEL clearing bug

The VIDIOC_DV_TIMINGS_CAP ioctl check wasn't added to determine_valid_ioctls().
This caused this ioctl to always return -ENOTTY.

The cause for this was that for 3.5 two patch series were merged, one
changing V4L2 core ioctl handling and one adding new functionality, and
some of the new functionality wasn't handled by the new V4L2 core code.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[ Taking it directly due to vacations  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull ARM SoC fixes for SPEAr from Olof Johansson:
 "These are arriving very late in the release cycle, but there has been
  a change of maintainers on the SPEAr platform and they have needed a
  while to get going.

  The patch count is higher than I would like at this point, but they're
  all relevant fixes and well-contained in their own platform code.  I
  still think it's suitable 3.5 material and I don't think it should
  increase the need for a -rc8 since they are so contained."

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: SPEAr600: Fix timer interrupt definition in spear600.dtsi
  ARM: dts: SPEAr320: Boot the board in EXTENDED_MODE
  ARM: dts: SPEAr320: Fix compatible string
  Clk: SPEAr1340: Update sys clock parent array
  clk: SPEAr1340: Fix clk enable register for uart1 and i2c1.
  ARM: SPEAr13xx: Fix Interrupt bindings
  Clk:spear6xx:Fix: Rename clk ids within predefined limit
  Clk:spear3xx:Fix: Rename clk ids within predefined limit
  clk:spear1310:Fix: Rename clk ids within predefined limit
  clk:spear1340:Fix: Rename clk ids within predefined limit

Please apply.

Thanks.
Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull CIFS fixes from Steve French.

* git://git.samba.org/sfrench/cifs-2.6:
  cifs: always update the inode cache with the results from a FIND_*
  cifs: when CONFIG_HIGHMEM is set, serialize the read/write kmaps
  cifs: on CONFIG_HIGHMEM machines, limit the rsize/wsize to the kmap space
  Initialise mid_q_entry before putting it on the pending queue

As reported by Alan Cox, and verified by Lin Ming, when a user
attempts to add a CIPSO option to a socket using the CIPSO_V4_TAG_LOCAL
tag the kernel dies a terrible death when it attempts to follow a NULL
pointer (the skb argument to cipso_v4_validate() is NULL when called via
the setsockopt() syscall).

This patch fixes this by first checking to ensure that the skb is
non-NULL before using it to find the incoming network interface.  In
the unlikely case where the skb is NULL and the user attempts to add
a CIPSO option with the _TAG_LOCAL tag we return an error as this is
not something we want to allow.

A simple reproducer, kindly supplied by Lin Ming, although you must
have the CIPSO DOI #3 configure on the system first or you will be
caught early in cipso_v4_validate():

	#include <sys/types.h>
	#include <sys/socket.h>
	#include <linux/ip.h>
	#include <linux/in.h>
	#include <string.h>

	struct local_tag {
		char type;
		char length;
		char info[4];
	};

	struct cipso {
		char type;
		char length;
		char doi[4];
		struct local_tag local;
	};

	int main(int argc, char **argv)
	{
		int sockfd;
		struct cipso cipso = {
			.type = IPOPT_CIPSO,
			.length = sizeof(struct cipso),
			.local = {
				.type = 128,
				.length = sizeof(struct local_tag),
			},
		};

		memset(cipso.doi, 0, 4);
		cipso.doi[3] = 3;

		sockfd = socket(AF_INET, SOCK_DGRAM, 0);
		#define SOL_IP 0
		setsockopt(sockfd, SOL_IP, IP_OPTIONS,
			&cipso, sizeof(struct cipso));

		return 0;
	}

CC: Lin Ming <mlin@ss.pku.edu.cn>
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Caused, AFAICS, by mismerge in commit ff9cb1c4 ("Merge branch
'for_linus' into for_linus_merged")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org  # 3.3+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for-3.5-spear-fixes' of http://git.stlinux.com/spear/linux-2.6:
  ARM: SPEAr600: Fix timer interrupt definition in spear600.dtsi
  ARM: dts: SPEAr320: Boot the board in EXTENDED_MODE
  ARM: dts: SPEAr320: Fix compatible string
  Clk: SPEAr1340: Update sys clock parent array
  clk: SPEAr1340: Fix clk enable register for uart1 and i2c1.
  ARM: SPEAr13xx: Fix Interrupt bindings
  Clk:spear6xx:Fix: Rename clk ids within predefined limit
  Clk:spear3xx:Fix: Rename clk ids within predefined limit
  clk:spear1310:Fix: Rename clk ids within predefined limit
  clk:spear1340:Fix: Rename clk ids within predefined limit

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

On spear320 device supported mode are:

   * AUTO_NET_SMII_MODE
   * AUTO_NET_MII_MODE
   * AUTO_EXP_MODE
   * SMALL_PRINTERS_MODE
   * EXTENDED_MODE

spear320-evb board is designed for EXTENDED_MODE only, hence it does not
boot correctly in current form where pinctrl part for some devices fail.

Configure and boot the SPEAr320 evaluation board in EXTENDED_MODE.
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

sys_clk has multiple parents and selection of parent depends on sys_clk_ctrl
register bit no. 23:25, with following possibilities

   0XX: pll1_clk
   10X: sys_synth_clk
   110: pll2_clk
   111: pll3_clk

Out of several possibilities (h/w wise) to select same clock parent for
sys_clk, current clock implementation was considering just one value.

When bootloader programmed different (valid) value to select a clock
parent then Linux breaks.

Here, we try to include all possibilities which can lead to same
clock selection thus making Linux independent of bootloader selection
values.
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

This patch is to fix typing mistake of clk enable register of i2c1 and
uart1.
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

   - Correct interrupt bindings for uart, ethernet and pmu.
   - Added interrupt binding for keyboard.
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

The max limit of con_id is 16 and dev_id is 20. As of now for spear6xx, many clk
ids are exceeding this predefined limit.

This patch is intended to rename clk ids like:
    mux_clk -> _mclk
    gate_clk -> _gclk
    synth_clk -> syn_clk
    ras_gen1_synth_gate_clk -> ras_syn1_gclk
    pll3_48m -> pll3_
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

The max limit of con_id is 16 and dev_id is 20. As of now for spear3xx, many clk
ids are exceeding this predefined limit.

This patch is intended to rename clk ids like:
    mux_clk -> _mclk
    gate_clk -> _gclk
    synth_clk -> syn_clk
    ras_gen1_synth_gate_clk -> ras_syn1_gclk
    ras_pll3_48m -> ras_pll3_
    pll3_48m -> pll3_
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

The max limit of con_id is 16 and dev_id is 20. As of now for spear1310, many
clk ids are exceeding this predefined limit.

This patch is intended to rename clk ids like:
    mux_clk -> _mclk
    gate_clk -> _gclk
    synth_clk -> syn_clk
    gmac_phy -> phy_
    gmii_125m_pad -> gmii_pad
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

The max limit of con_id is 16 and dev_id is 20. As of now for spear1340, many
clk ids are exceeding this predefined limit.

This patch rename clk ids like:
    mux_clk -> _mclk
    gate_clk -> _gclk
    synth_clk -> syn_clk
    gmac_phy -> phy_
    gmii_125m_pad_ -> gmii_pad
Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>

Sparse complains about this because:
drivers/block/rbd.c:996:20: warning: cast to restricted __le32
drivers/block/rbd.c:996:20: warning: cast from restricted __le16

These are set in osd_req_encode_op() and they are le16.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit 895cfcc8)

ceph_snap_context->snaps is an u64 array
Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit f9f9a190)

In ancient times, the messenger could both initiate and accept connections.
An artifact if that was data structures to store/process an incoming
ceph_msg_connect request and send an outgoing ceph_msg_connect_reply.
Sadly, the negotiation code was referencing those structures and ignoring
important information (like the peer's connect_seq) from the correct ones.

Among other things, this fixes tight reconnect loops where the server sends
RETRY_SESSION and we (the client) retries with the same connect_seq as last
time.  This bug pretty easily triggered by injecting socket failures on the
MDS and running some fs workload like workunits/direct_io/test_sync_io.
Signed-off-by: Sage Weil <sage@inktank.com>

Merge Andrew's remaining patches for 3.5:
 "Nine fixes"

* Merge emailed patches from Andrew Morton <akpm@linux-foundation.org>: (9 commits)
  mm: fix lost kswapd wakeup in kswapd_stop()
  m32r: make memset() global for CONFIG_KERNEL_BZIP2=y
  m32r: add memcpy() for CONFIG_KERNEL_GZIP=y
  m32r: consistently use "suffix-$(...)"
  m32r: fix 'fix breakage from "m32r: use generic ptrace_resume code"' fallout
  m32r: fix pull clearing RESTORE_SIGMASK into block_sigmask() fallout
  m32r: remove duplicate definition of PTRACE_O_TRACESYSGOOD
  mn10300: fix "pull clearing RESTORE_SIGMASK into block_sigmask()" fallout
  bootmem: make ___alloc_bootmem_node_nopanic() really nopanic

Offlining memory may block forever, waiting for kswapd() to wake up
because kswapd() does not check the event kthread->should_stop before
sleeping.

The proper pattern, from Documentation/memory-barriers.txt, is:

   ---  waker  ---
   event_indicated = 1;
   wake_up_process(event_daemon);

   ---  sleeper  ---
   for (;;) {
      set_current_state(TASK_UNINTERRUPTIBLE);
      if (event_indicated)
         break;
      schedule();
   }

   set_current_state() may be wrapped by:
      prepare_to_wait();

In the kswapd() case, event_indicated is kthread->should_stop.

  === offlining memory (waker) ===
   kswapd_stop()
      kthread_stop()
         kthread->should_stop = 1
         wake_up_process()
         wait_for_completion()

  ===  kswapd_try_to_sleep (sleeper) ===
   kswapd_try_to_sleep()
      prepare_to_wait()
           .
           .
      schedule()
           .
           .
      finish_wait()

The schedule() needs to be protected by a test of kthread->should_stop,
which is wrapped by kthread_should_stop().

Reproducer:
   Do heavy file I/O in background.
   Do a memory offline/online in a tight loop
Signed-off-by: Aaditya Kumar <aaditya.kumar@ap.sony.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>