Eric Dumazet says:

====================
net: provide common RSS key infrastructure

RSS (Receive Side Scaling) uses a 40 bytes key to provide hash for incoming
packets to select appropriate incoming queue on NIC.

Hash algo (Toeplitz) is also well known and documented by Microsoft
(search for "Verifying the RSS Hash Calculation")

Problem is that some drivers use a well known key.
It makes very easy for attackers to target one particular RX queue,
knowing that number of RX queues is a power of two, or at least some
small number.

Other drivers use a random value per port, making difficult
tuning on bonding setups.

Lets add a common infrastructure, so that host gets an unique
RSS key, and drivers do not have to worry about this.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use netdev_rss_key_fill() helper, as it provides better support for some
bonding setups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.

Also provide ethtool -x support to fetch RSS key
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use netdev_rss_key_fill() helper, as it provides better support for some
bonding setups.
Rename rss_hkey local variable to rss_key to have consistent name among
drivers.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use netdev_rss_key_fill() helper, as it provides better support for some
bonding setups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use of well known RSS key increases attack surface.
Switch to a random one, using generic helper so that all
ports share a common key.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Prashant Sreedharan <prashant@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use netdev_rss_key_fill() helper, as it provides better support for some
bonding setups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ariel Elior <ariel.elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use netdev_rss_key_fill() helper, as it provides better support for some
bonding setups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lendacky, Thomas <Thomas.Lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RSS (Receive Side Scaling) typically uses Toeplitz hash and a 40 or 52 bytes
RSS key.

Some drivers use a constant (and well known key), some drivers use a random
key per port, making bonding setups hard to tune. Well known keys increase
attack surface, considering that number of queues is usually a power of two.

This patch provides infrastructure to help drivers doing the right thing.

netdev_rss_key_fill() should be used by drivers to initialize their RSS key,
even if they provide ethtool -X support to let user redefine the key later.

A new /proc/sys/net/core/netdev_rss_key file can be used to get the host
RSS key even for drivers not providing ethtool -x support, in case some
applications want to precisely setup flows to match some RX queues.

Tested:

myhost:~# cat /proc/sys/net/core/netdev_rss_key
11:63:99:bb:79:fb:a5:a7:07:45:b2:20:bf:02:42:2d:08:1a:dd:19:2b:6b:23:ac:56:28:9d:70:c3:ac:e8:16:4b:b7:c1:10:53:a4:78:41:36:40:74:b6:15:ca:27:44:aa:b3:4d:72

myhost:~# ethtool -x eth0
RX flow hash indirection table for eth0 with 8 RX ring(s):
    0:      0     1     2     3     4     5     6     7
RSS hash key:
11:63:99:bb:79:fb:a5:a7:07:45:b2:20:bf:02:42:2d:08:1a:dd:19:2b:6b:23:ac:56:28:9d:70:c3:ac:e8:16:4b:b7:c1:10:53:a4:78:41
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Andrew Lunn says:

====================
Add temperature reading and registers dump to mv88e6171

These patches centralize the temperature sensor reading code, and then
make use of it with the mv88e6171 which has a compatible
sensor. Additionally, support is added for reading the mv88e6171 via
ethtool.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The infrastructure can now report switch registers to ethtool.
Add support for it to the mv88e6171 driver.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

This chip also has a temperature sensor which can be read using the
common code. In order to use it, add the needed mutex protection for
accessing registers via the shared code.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

The method to read the temperature used in the mve6123_61_65 driver
can also be used for other chips. Move the code into the shared code
base of mv88e6xxx.c.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

kcalloc manages count*sizeof overflow.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

kmalloc_array manages count*sizeof overflow.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There is no reason to limit the amount of possible links to a
neighboring node to 2. If we have more then two bearers we can also
establish more links.
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Reviewed-By: Jon Maloy <jon.maloy@ericsson.com>
cc: Ying Xue <ying.xue@windriver.com>
cc: Erik Hugne <erik.hugne@ericsson.com>
cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit e5a2c899.

	Commit e5a2c899 introduced an alternative_call, arch_fast_hash2,
that selects between __jhash2 and __intel_crc4_2_hash based on the
X86_FEATURE_XMM4_2.

	Unfortunately, the alternative_call system does not appear to be
suitable for use with C functions, as register usage is not handled
properly for the called functions.  The __jhash2 function in particular
clobbers registers that are not preserved when called via
alternative_call, resulting in a panic for direct callers of
arch_fast_hash2 on older CPUs lacking sse4_2.  It is possible that
__intel_crc4_2_hash works merely by chance because it uses fewer
registers.

	This commit was suggested as the source of the problem by Jesse
Gross <jesse@nicira.com>.
Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add dependency on INET to fix following build error. I have also
fixed MPLS dependency.

ERROR: "ip_route_output_flow" [net/openvswitch/openvswitch.ko]
undefined!
make[1]: *** [__modpost] Error 1
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	drivers/net/ethernet/chelsio/cxgb4vf/sge.c
	drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c

sge.c was overlapping two changes, one to use the new
__dev_alloc_page() in net-next, and one to use s->fl_pg_order in net.

ixgbe_phy.c was a set of overlapping whitespace changes.
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull virtio bugfix from Michael S Tsirkin:
 "This fixes a crash in virtio console multi-channel mode that got
  introduced in -rc1"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_console: move early VQ enablement

Pull networking fixes from David Miller:

 1) sunhme driver lacks DMA mapping error checks, based upon a report by
    Meelis Roos.

 2) Fix memory leak in mvpp2 driver, from Sudip Mukherjee.

 3) DMA memory allocation sizes are wrong in systemport ethernet driver,
    fix from Florian Fainelli.

 4) Fix use after free in mac80211 defragmentation code, from Johannes
    Berg.

 5) Some networking uapi headers missing from Kbuild file, from Stephen
    Hemminger.

 6) TUN driver gets csum_start offset wrong when VLAN accel is enabled,
    and macvtap has a similar bug, from Herbert Xu.

 7) Adjust several tunneling drivers to set dev->iflink after registry,
    because registry sets that to -1 overwriting whatever we did.  From
    Steffen Klassert.

 8) Geneve forgets to set inner tunneling type, causing GSO segmentation
    to fail on some NICs.  From Jesse Gross.

 9) Fix several locking bugs in stmmac driver, from Fabrice Gasnier and
    Giuseppe CAVALLARO.

10) Fix spurious timeouts with NewReno on low traffic connections, from
    Marcelo Leitner.

11) Fix descriptor updates in enic driver, from Govindarajulu
    Varadarajan.

12) PPP calls bpf_prog_create() with locks held, which isn't kosher.
    Fix from Takashi Iwai.

13) Fix NULL deref in SCTP with malformed INIT packets, from Daniel
    Borkmann.

14) psock_fanout selftest accesses past the end of the mmap ring, fix
    from Shuah Khan.

15) Fix PTP timestamping for VLAN packets, from Richard Cochran.

16) netlink_unbind() calls in netlink pass wrong initial argument, from
    Hiroaki SHIMODA.

17) vxlan socket reuse accidently reuses a socket when the address
    family is different, so we have to explicitly check this, from
    Marcelo Lietner.

18) Fix missing include in nft_reject_bridge.c breaking the build on ppc
    and other architectures, from Guenter Roeck.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (75 commits)
  vxlan: Do not reuse sockets for a different address family
  smsc911x: power-up phydev before doing a software reset.
  lib: rhashtable - Remove weird non-ASCII characters from comments
  net/smsc911x: Fix delays in the PHY enable/disable routines
  net/smsc911x: Fix rare soft reset timeout issue due to PHY power-down mode
  netlink: Properly unbind in error conditions.
  net: ptp: fix time stamp matching logic for VLAN packets.
  cxgb4 : dcb open-lldp interop fixes
  selftests/net: psock_fanout seg faults in sock_fanout_read_ring()
  net: bcmgenet: apply MII configuration in bcmgenet_open()
  net: bcmgenet: connect and disconnect from the PHY state machine
  net: qualcomm: Fix dependency
  ixgbe: phy: fix uninitialized status in ixgbe_setup_phy_link_tnx
  net: phy: Correctly handle MII ioctl which changes autonegotiation.
  ipv6: fix IPV6_PKTINFO with v4 mapped
  net: sctp: fix memory leak in auth key management
  net: sctp: fix NULL pointer dereference in af->from_addr_param on malformed packet
  net: ppp: Don't call bpf_prog_create() in ppp_lock
  net/mlx4_en: Advertize encapsulation offloads features only when VXLAN tunnel is set
  cxgb4 : Fix bug in DCB app deletion
  ...

Merge misc fixes from Andrew Morton:
 "15 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  MAINTAINERS: add IIO include files
  kernel/panic.c: update comments for print_tainted
  mem-hotplug: reset node present pages when hot-adding a new pgdat
  mem-hotplug: reset node managed pages when hot-adding a new pgdat
  mm/debug-pagealloc: correct freepage accounting and order resetting
  fanotify: fix notification of groups with inode & mount marks
  mm, compaction: prevent infinite loop in compact_zone
  mm: alloc_contig_range: demote pages busy message from warn to info
  mm/slab: fix unalignment problem on Malta with EVA due to slab merge
  mm/page_alloc: restrict max order of merging on isolated pageblock
  mm/page_alloc: move freepage counting logic to __free_one_page()
  mm/page_alloc: add freepage on isolate pageblock to correct buddy list
  mm/page_alloc: fix incorrect isolation behavior by rechecking migratetype
  mm/compaction: skip the range until proper target pageblock is met
  zram: avoid kunmap_atomic() of a NULL pointer

Pull Ceph fixes from Sage Weil:
 "There is an overflow bug fix for cephfs from Zheng, a fix for handling
  large authentication ticket buffers in libceph from Ilya, and a few
  fixes for the request handling code from Ilya that affect RBD volumes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  libceph: change from BUG to WARN for __remove_osd() asserts
  libceph: clear r_req_lru_item in __unregister_linger_request()
  libceph: unlink from o_linger_requests when clearing r_osd
  libceph: do not crash on large auth tickets
  ceph: fix flush tid comparision

Pull HID fixes from Jiri Kosina:

 - fix for an oops in HID core upon repeated subdriver insertion/removal
   under certain circumstances, by Benjamin Tissoires

 - quirk for another Elan Touchscreen device, by Adel Gadllah

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: core: cleanup .claimed field on disconnect
  HID: usbhid: enable always-poll quirk for Elan Touchscreen 0103

Files under include/linux/iio were not reported as part of the IIO
subsystem.
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Reported-by: Cristina Ciocan <cristina.ciocan@intel.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 69361eef ("panic: add TAINT_SOFTLOCKUP") added the 'L' flag,
but failed to update the comments for print_tainted().  So, update the
comments.
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When memory is hot-added, all the memory is in offline state.  So clear
all zones' present_pages because they will be updated in online_pages()
and offline_pages().  Otherwise, /proc/zoneinfo will corrupt:

When the memory of node2 is offline:

  # cat /proc/zoneinfo
  ......
  Node 2, zone   Movable
  ......
        spanned  8388608
        present  8388608
        managed  0

When we online memory on node2:

  # cat /proc/zoneinfo
  ......
  Node 2, zone   Movable
  ......
        spanned  8388608
        present  16777216
        managed  8388608
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>	[3.16+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In free_area_init_core(), zone->managed_pages is set to an approximate
value for lowmem, and will be adjusted when the bootmem allocator frees
pages into the buddy system.

But free_area_init_core() is also called by hotadd_new_pgdat() when
hot-adding memory.  As a result, zone->managed_pages of the newly added
node's pgdat is set to an approximate value in the very beginning.

Even if the memory on that node has node been onlined,
/sys/device/system/node/nodeXXX/meminfo has wrong value:

  hot-add node2 (memory not onlined)
  cat /sys/device/system/node/node2/meminfo
  Node 2 MemTotal:       33554432 kB
  Node 2 MemFree:               0 kB
  Node 2 MemUsed:        33554432 kB
  Node 2 Active:                0 kB

This patch fixes this problem by reset node managed pages to 0 after
hot-adding a new node.

1. Move reset_managed_pages_done from reset_node_managed_pages() to
   reset_all_zones_managed_pages()
2. Make reset_node_managed_pages() non-static
3. Call reset_node_managed_pages() in hotadd_new_pgdat() after pgdat
   is initialized
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>	[3.16+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

One thing I did in this patch is fixing freepage accounting.  If we
clear guard page and link it onto isolate buddy list, we should not
increase freepage count.  This patch adds conditional branch to skip
counting in this case.  Without this patch, this overcounting happens
frequently if guard order is set and CMA is used.

Another thing fixed in this patch is the target to reset order.  In
__free_one_page(), we check the buddy page whether it is a guard page or
not.  And, if so, we should clear guard attribute on the buddy page and
reset order of it to 0.  But, current code resets original page's order
rather than buddy one's.  Maybe, this doesn't have any problem, because
whole merged page's order will be re-assigned soon.  But, it is better
to correct code.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fsnotify() needs to merge inode and mount marks lists when notifying
groups about events so that ignore masks from inode marks are reflected
in mount mark notifications and groups are notified in proper order
(according to priorities).

Currently the sorting of the lists done by fsnotify_add_inode_mark() /
fsnotify_add_vfsmount_mark() and fsnotify() differed which resulted
ignore masks not being used in some cases.

Fix the problem by always using the same comparison function when
sorting / merging the mark lists.

Thanks to Heinrich Schuchardt for improvements of my patch.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=87721Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Several people have reported occasionally seeing processes stuck in
compact_zone(), even triggering soft lockups, in 3.18-rc2+.

Testing a revert of commit e14c720e ("mm, compaction: remember
position within pageblock in free pages scanner") fixed the issue,
although the stuck processes do not appear to involve the free scanner.

Finally, by code inspection, the bug was found in isolate_migratepages()
which uses a slightly different condition to detect if the migration and
free scanners have met, than compact_finished().  That has not been a
problem until commit e14c720e allowed the free scanner position
between individual invocations to be in the middle of a pageblock.

In a relatively rare case, the migration scanner position can end up at
the beginning of a pageblock, with the free scanner position in the
middle of the same pageblock.  If it's the migration scanner's turn,
isolate_migratepages() exits immediately (without updating the
position), while compact_finished() decides to continue compaction,
resulting in a potentially infinite loop.  The system can recover only
if another process creates enough high-order pages to make the watermark
checks in compact_finished() pass.

This patch fixes the immediate problem by bumping the migration
scanner's position to meet the free scanner in isolate_migratepages(),
when both are within the same pageblock.  This causes compact_finished()
to terminate properly.  A more robust check in compact_finished() is
planned as a cleanup for better future maintainability.

Fixes: e14c720e ("mm, compaction: remember position within pageblock in free pages scanner)
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: P. Christeas <xrg@linux.gr>
Tested-by: P. Christeas <xrg@linux.gr>
Link: http://marc.info/?l=linux-mm&m=141508604232522&w=2Reported-by: Norbert Preining <preining@logic.at>
Tested-by: Norbert Preining <preining@logic.at>
Link: https://lkml.org/lkml/2014/11/4/904Reported-by: Pavel Machek <pavel@ucw.cz>
Link: https://lkml.org/lkml/2014/11/7/164
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Having test_pages_isolated failure message as a warning confuses users
into thinking that it is more serious than it really is.  In reality, if
called via CMA, allocation will be retried so a single
test_pages_isolated failure does not prevent allocation from succeeding.

Demote the warning message to an info message and reformat it such that
the text "failed" does not appear and instead a less worrying "PFNS
busy" is used.

This message is trivially reproducible on a 10GB x86 machine on 3.16.y
kernels configured with CONFIG_DMA_CMA.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Unlike SLUB, sometimes, object isn't started at the beginning of the
slab in SLAB.  This causes the unalignment problem after slab merging is
supported by commit 12220dea ("mm/slab: support slab merge").

Following is the report from Markos that fail to boot on Malta with EVA.

    Calibrating delay loop... 19.86 BogoMIPS (lpj=99328)
    pid_max: default: 32768 minimum: 301
    Mount-cache hash table entries: 4096 (order: 0, 16384 bytes)
    Mountpoint-cache hash table entries: 4096 (order: 0, 16384 bytes)
    Kernel bug detected[#1]:
    CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.0-05639-g12220dea #1631
    task: 1f04f5d8 ti: 1f050000 task.ti: 1f050000
    epc   : 80141190 alloc_unbound_pwq+0x234/0x304
        Not tainted
    ra    : 80141184 alloc_unbound_pwq+0x228/0x304
    Process swapper/0 (pid: 1, threadinfo=1f050000, task=1f04f5d8, tls=00000000)
    Call Trace:
      alloc_unbound_pwq+0x234/0x304
      apply_workqueue_attrs+0x11c/0x294
      __alloc_workqueue_key+0x23c/0x470
      init_workqueues+0x320/0x400
      do_one_initcall+0xe8/0x23c
      kernel_init_freeable+0x9c/0x224
      kernel_init+0x10/0x100
      ret_from_kernel_thread+0x14/0x1c
    [ end trace cb88537fdc8fa200 ]
    Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

alloc_unbound_pwq() allocates slab object from pool_workqueue.  This
kmem_cache requires 256 bytes alignment, but, current merging code
doesn't honor that, and merge it with kmalloc-256.  kmalloc-256 requires
only cacheline size alignment so that above failure occurs.  However, in
x86, kmalloc-256 is luckily aligned in 256 bytes, so the problem didn't
happen on it.

To fix this problem, this patch introduces alignment mismatch check in
find_mergeable().  This will fix the problem.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Markos Chandras <Markos.Chandras@imgtec.com>
Tested-by: Markos Chandras <Markos.Chandras@imgtec.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.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>