This patch reverts 1ba6e0b5 ("mm: numa: split_huge_page: transfer the
NUMA type from the pmd to the pte"). If a huge page is being split due
a protection change and the tail will be in a PROT_NONE vma then NUMA
hinting PTEs are temporarily created in the protected VMA.

 VM_RW|VM_PROTNONE
|-----------------|
      ^
      split here

In the specific case above, it should get fixed up by change_pte_range()
but there is a window of opportunity for weirdness to happen. Similarly,
if a huge page is shrunk and split during a protection update but before
pmd_numa is cleared then a pte_numa can be left behind.

Instead of adding complexity trying to deal with the case, this patch
will not mark PTEs NUMA when splitting a huge page. NUMA hinting faults
will not be triggered which is marginal in comparison to the complexity
in dealing with the corner cases during THP split.

Cc: stable@vger.kernel.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

A migration entry is marked as write if pte_write was true at the time the
entry was created. The VMA protections are not double checked when migration
entries are being removed as mprotect marks write-migration-entries as
read. It means that potentially we take a spurious fault to mark PTEs write
again but it's straight-forward. However, there is a race between write
migrations being marked read and migrations finishing. This potentially
allows a PTE to be write that should have been read. Close this race by
double checking the VMA permissions using maybe_mkwrite when migration
completes.

[torvalds@linux-foundation.org: use maybe_mkwrite]
Cc: stable@vger.kernel.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull networking fixes from David Miller:

 1) Don't halt the firmware in r8152 driver, from Hayes Wang.

 2) Handle full sized 802.1ad frames in bnx2 and tg3 drivers properly,
    from Vlad Yasevich.

 3) Don't sleep while holding tx_clean_lock in netxen driver, fix from
    Manish Chopra.

 4) Certain kinds of ipv6 routes can end up endlessly failing the route
    validation test, causing it to be re-looked up over and over again.
    This particularly kills input route caching in TCP sockets.  Fix
    from Hannes Frederic Sowa.

 5) netvsc_start_xmit() has a use-after-free access to skb->len, fix
    from K Y Srinivasan.

 6) Fix matching of inverted containers in ematch module, from Ignacy
    Gawędzki.

 7) Aggregation of GRO frames via SKB ->frag_list for linear skbs isn't
    handled properly, regression fix from Eric Dumazet.

 8) Don't test return value of ipv4_neigh_lookup(), which returns an
    error pointer, against NULL.  From WANG Cong.

 9) Fix an old regression where we mistakenly allow a double add of the
    same tunnel.  Fixes from Steffen Klassert.

10) macvtap device delete and open can run in parallel and corrupt lists
    etc., fix from Vlad Yasevich.

11) Fix build error with IPV6=m NETFILTER_XT_TARGET_TPROXY=y, from Pablo
    Neira Ayuso.

12) rhashtable_destroy() triggers lockdep splats, fix also from Pablo.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (32 commits)
  bna: Update Maintainer Email
  r8152: disable power cut for RTL8153
  r8152: remove clearing bp
  bnx2: Correctly receive full sized 802.1ad fragmes
  tg3: Allow for recieve of full-size 8021AD frames
  r8152: fix setting RTL8152_UNPLUG
  netxen: Fix bug in Tx completion path.
  netxen: Fix BUG "sleeping function called from invalid context"
  ipv6: remove rt6i_genid
  hyperv: Fix a bug in netvsc_start_xmit()
  net: stmmac: fix stmmac_pci_probe failed when CONFIG_HAVE_CLK is selected
  ematch: Fix matching of inverted containers.
  gro: fix aggregation for skb using frag_list
  neigh: check error pointer instead of NULL for ipv4_neigh_lookup()
  ip6_gre: Return an error when adding an existing tunnel.
  ip6_vti: Return an error when adding an existing tunnel.
  ip6_tunnel: Return an error when adding an existing tunnel.
  ip6gre: add a rtnl link alias for ip6gretap
  net/mlx4_core: Allow not to specify probe_vf in SRIOV IB mode
  r8152: fix the carrier off when autoresuming
  ...

Update the maintainer email for BNA driver.
Signed-off-by: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Hayes Wang says:

====================
r8152: patches about firmware

The patches fix the issues when the firmware exists.

For the multiple OS, the firmware may be loaded by the
driver of the other OS. And the Linux driver has influences
on it.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The firmware would be clear when the power cut is enabled for
RTL8153.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The xxx_clear_bp() is used to halt the firmware. It only necessary
for updating the new firmware. Besides, depend on the version of
the current firmware, it may have problem to halt the firmware
directly. Finally, halt the firmware would let the firmware code
useless, and the bugs which are fixed by the firmware would occur.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This driver, similar to tg3, has a check that will
cause full sized 802.1ad frames to be dropped.  The
frame will be larger then the standard mtu due to the
presense of vlan header that has not been stripped.
The driver should not drop this frame and should process
it just like it does for 802.1q.

CC: Sony Chacko <sony.chacko@qlogic.com>
CC: Dept-HSGLinuxNICDev@qlogic.com
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When receiving a vlan-tagged frame that still contains
a vlan header, the length of the packet will be greater
then MTU+ETH_HLEN since it will account of the extra
vlan header.  TG3 checks this for the case for 802.1Q,
but not for 802.1ad.  As a result, full sized 802.1ad
frames get dropped by the card.

Add a check for 802.1ad protocol when receving full
sized frames.
Suggested-by: Prashant Sreedharan <prashant@broadcom.com>
CC: Prashant Sreedharan <prashant@broadcom.com>
CC: Michael Chan <mchan@broadcom.com>
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull nfsd bugfix from Bruce Fields:
 "This fixes a data corruption bug introduced by the v3.16 xdr encoding
  rewrite.  I haven't managed to reproduce it myself yet, but it's
  apparently not hard to hit given the right workload"

* 'for-3.17' of git://linux-nfs.org/~bfields/linux:
  nfsd4: fix corruption of NFSv4 read data

Pull ARM fixes from Russell King:
 "Some further ARM fixes:
   - another build fix for the kprobes test code
   - a fix for no kuser helpers for the set_tls code, which oopsed on
     noMMU hardware
   - a fix for alignment handler with neon opcodes being misinterpreted
   - turning off the hardware access support, which is not implemented
   - a build fix for the v7 coherency exiting code, which can be built
     in non-v7 environments (but still only executed on v7 CPUs)"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8179/1: kprobes-test: Fix compile error "bad immediate value for offset"
  ARM: 8178/1: fix set_tls for !CONFIG_KUSER_HELPERS
  ARM: 8177/1: cacheflush: Fix v7_exit_coherency_flush exynos build breakage on ARMv6
  ARM: 8165/1: alignment: don't break misaligned NEON load/store
  ARM: 8164/1: mm: clear SCTLR.HA instead of setting it for LPAE

The flag of RTL8152_UNPLUG should only be set when the device is
unplugged, not each time the rtl8152_disconnect() is called.
Otherwise, the device wouldn't be stopped normally.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Manish Chopra says:

====================
netxen: Bug fixes.

This series fixes some TX specific issues.
* Move spin_lock(tx_clean_lock) in down path to fix
  atomic sleep bug (Reported by Mike Galbraith).
* Fix hang in interface down while running traffic.

Please consider applying this to 'net'.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

o Driver is not updating sw_consumer while processing Tx completion
  when interface is going down. Due to this interface down path gets
  stuck forever waiting for NAPI to complete.
Signed-off-by: Manish Chopra <manish.chopra@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

o __netxen_nic_down() function might sleep while holding spinlock_t(tx_clean_lock).
  Acquire this lock for only releasing TX buffers instead of taking it
  for whole down path.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Manish Chopra <manish.chopra@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The calculation of page_ptr here is wrong in the case the read doesn't
start at an offset that is a multiple of a page.

The result is that nfs4svc_encode_compoundres sets rq_next_page to a
value one too small, and then the loop in svc_free_res_pages may
incorrectly fail to clear a page pointer in rq_respages[].

Pages left in rq_respages[] are available for the next rpc request to
use, so xdr data may be written to that page, which may hold data still
waiting to be transmitted to the client or data in the page cache.

The observed result was silent data corruption seen on an NFSv4 client.

We tag this as "fixing" 05638dc7 because that commit exposed this
bug, though the incorrect calculation predates it.

Particular thanks to Andrea Arcangeli and David Gilbert for analysis and
testing.

Fixes: 05638dc7 "nfsd4: simplify server xdr->next_page use"
Cc: stable@vger.kernel.org
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Eric Dumazet noticed that all no-nonexthop or no-gateway routes which
are already marked DST_HOST (e.g. input routes routes) will always be
invalidated during sk_dst_check. Thus per-socket dst caching absolutely
had no effect and early demuxing had no effect.

Thus this patch removes rt6i_genid: fn_sernum already gets modified during
add operations, so we only must ensure we mutate fn_sernum during ipv6
address remove operations. This is a fairly cost extensive operations,
but address removal should not happen that often. Also our mtu update
functions do the same and we heard no complains so far. xfrm policy
changes also cause a call into fib6_flush_trees. Also plug a hole in
rt6_info (no cacheline changes).

I verified via tracing that this change has effect.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: YOSHIFUJI Hideaki <hideaki@yoshifuji.org>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

When compiling kprobes-test-arm.c the following error has been observed

/tmp/ccoT403o.s:21439: Error: bad immediate value for offset (4168)

This is caused by the compiler spilling it's literal pool too far away
from the site which is trying to reference it with a PC relative load.
This arises because the compiler is underestimating the size of the
inline assembler code present, which apparently it approximates as 4
bytes per line or instruction.

We fix this problem by moving the operations which generate more than
4 bytes out of the text section. Specifically, moving the .ascii
directives to the .rodata section.
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Joachim Eastwood reports that commit fbfb872f "ARM: 8148/1: flush
TLS and thumbee register state during exec" causes a boot-time crash
on a Cortex-M4 nommu system:

Freeing unused kernel memory: 68K (281e5000 - 281f6000)
Unhandled exception: IPSR = 00000005 LR = fffffff1
CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
task: 29834000 ti: 29832000 task.ti: 29832000
PC is at flush_thread+0x2e/0x40
LR is at flush_thread+0x21/0x40
pc : [<2800954a>] lr : [<2800953d>] psr: 4100000b
sp : 29833d60 ip : 00000000 fp : 00000001
r10: 00003cf8 r9 : 29b1f000 r8 : 00000000
r7 : 29b0bc00 r6 : 29834000 r5 : 29832000 r4 : 29832000
r3 : ffff0ff0 r2 : 29832000 r1 : 00000000 r0 : 282121f0
xPSR: 4100000b
CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
[<2800afa5>] (unwind_backtrace) from [<2800a327>] (show_stack+0xb/0xc)
[<2800a327>] (show_stack) from [<2800a963>] (__invalid_entry+0x4b/0x4c)

The problem is that set_tls is attempting to clear the TLS location in
the kernel-user helper page, which isn't set up on V7M.

Fix this by guarding the write to the kuser helper page with
a CONFIG_KUSER_HELPERS ifdef.

Fixes: fbfb872f ARM: 8148/1: flush TLS and thumbee register state during exec
Reported-by: Joachim Eastwood <manabian@gmail.com>
Tested-by: Joachim Eastwood <manabian@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This fixes build breakage of platsmp.c if ARMv6 was chosen for compile
time options (e.g. by building allmodconfig):

$ make allmodconfig
$ make
  CC      arch/arm/mach-exynos/platsmp.o
/tmp/ccdQM0Eg.s: Assembler messages:
/tmp/ccdQM0Eg.s:432: Error: selected processor does not support ARM mode `isb '
/tmp/ccdQM0Eg.s:437: Error: selected processor does not support ARM mode `isb '
/tmp/ccdQM0Eg.s:438: Error: selected processor does not support ARM mode `dsb '
make[1]: *** [arch/arm/mach-exynos/platsmp.o] Error 1

The error was introduced in commit "ARM: EXYNOS: Move code from
hotplug.c to platsmp.c".  Previously code using
v7_exit_coherency_flush() macro was built with '-march=armv7-a' flag but
this flag dissapeared during the movement.

Fix this by annotating the v7_exit_coherency_flush() asm code with
armv7-a architecture.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reported-by: Mark Brown <broonie@kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

After the packet is successfully sent, we should not touch the skb
as it may have been freed. This patch is based on the work done by
Long Li <longli@microsoft.com>.

In this version of the patch I have fixed issues pointed out by David.
David, please queue this up for stable.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Long Li <longli@microsoft.com>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the CONFIG_HAVE_CLK is selected for the system, the stmmac_pci_probe
will fail with dmesg:
[    2.167225] stmmaceth 0000:00:14.6: enabling device (0000 -> 0002)
[    2.178267] stmmaceth 0000:00:14.6: enabling bus mastering
[    2.178436] stmmaceth 0000:00:14.6: irq 24 for MSI/MSI-X
[    2.178703] stmmaceth 0000:00:14.6: stmmac_dvr_probe: warning: cannot
get CSR clock
[    2.186503] stmmac_pci_probe: main driver probe failed
[    2.194003] stmmaceth 0000:00:14.6: disabling bus mastering
[    2.196473] stmmaceth: probe of 0000:00:14.6 failed with error -2

This patch fix the issue by breaking the dependency to devm_clk_get()
as the CSR clock can be obtained at priv->plat->clk_csr from pci driver.
Reported-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Negated expressions and sub-expressions need to have their flags checked for
TCF_EM_INVERT and their result negated accordingly.
Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

In commit 8a29111c ("net: gro: allow to build full sized skb")
I added a regression for linear skb that traditionally force GRO
to use the frag_list fallback.

Erez Shitrit found that at most two segments were aggregated and
the "if (skb_gro_len(p) != pinfo->gso_size)" test was failing.

This is because pinfo at this spot still points to the last skb in the
chain, instead of the first one, where we find the correct gso_size
information.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 8a29111c ("net: gro: allow to build full sized skb")
Reported-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fixes: commit f187bc6e ("ipv4: No need to set generic neighbour pointer")
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull slave-dmaengine fixes from Vinod Koul:
 "Two small fixes for omap dmaengine driver which fixes cyclic suspend
  and resume"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: omap-dma: Restore the CLINK_CTRL in resume path
  dmaengine: omap-dma: Add memory barrier to dma_resume path

Steffen Klassert says:

====================
ipv6: Return an error when adding an already existing tunnel

The ipv6 tunnel locate functions should not return an existing
tunnel if create is true. Otherwise it is possible to add the
same tunnel multiple times without getting an error.

All our ipv6 tunnels have this bug from the very beginning.
Only the sit tunnel was fixed some years ago with:

commit 8db99e57 ("sit: Fail to create tunnel, if it already exists").

This patchset fixes the remaining ipv6 tunnels.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

ip6gre_tunnel_locate() should not return an existing tunnel if
create is true. Otherwise it is possible to add the same
tunnel multiple times without getting an error.

So return NULL if the tunnel that should be created already
exists.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

vti6_locate() should not return an existing tunnel if
create is true. Otherwise it is possible to add the same
tunnel multiple times without getting an error.

So return NULL if the tunnel that should be created already
exists.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ip6_tnl_locate() should not return an existing tunnel if
create is true. Otherwise it is possible to add the same
tunnel multiple times without getting an error.

So return NULL if the tunnel that should be created already
exists.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull vfs fixes from Al Viro:
 "Assorted fixes + unifying __d_move() and __d_materialise_dentry() +
  minimal regression fix for d_path() of victims of overwriting rename()
  ported on top of that"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: Don't exchange "short" filenames unconditionally.
  fold swapping ->d_name.hash into switch_names()
  fold unlocking the children into dentry_unlock_parents_for_move()
  kill __d_materialise_dentry()
  __d_materialise_dentry(): flip the order of arguments
  __d_move(): fold manipulations with ->d_child/->d_subdirs
  don't open-code d_rehash() in d_materialise_unique()
  pull rehashing and unlocking the target dentry into __d_materialise_dentry()
  ufs: deal with nfsd/iget races
  fuse: honour max_read and max_write in direct_io mode
  shmem: fix nlink for rename overwrite directory

Pull cgroup fixes from Tejun Heo:
 "This is quite late but these need to be backported anyway.

  This is the fix for a long-standing cpuset bug which existed from
  2009.  cpuset makes use of PF_SPREAD_{PAGE|SLAB} flags to modify the
  task's memory allocation behavior according to the settings of the
  cpuset it belongs to; unfortunately, when those flags have to be
  changed, cpuset did so directly even whlie the target task is running,
  which is obviously racy as task->flags may be modified by the task
  itself at any time.  This obscure bug manifested as corrupt
  PF_USED_MATH flag leading to a weird crash.

  The bug is fixed by moving the flag to task->atomic_flags.  The first
  two are prepatory ones to help defining atomic_flags accessors and the
  third one is the actual fix"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags
  sched: add macros to define bitops for task atomic flags
  sched: fix confusing PFA_NO_NEW_PRIVS constant

Pull ARM SoC fixes from Olof Johansson:
 "Here's our last set of fixes for 3.17.  Most of these are for TI
  platforms, fixing some noisy Kconfig issues, runtime clock and power
  issues on several platforms and NAND timings on DRA7.

  There are also a couple of bug fixes for i.MX, one for QCOM and a
 small fix to avoid section mismatch noise on PXA.

  Diffstat looks large, partially due to some tables being updated and
  thus touching many lines.  The qcom gsbi change also restructures
  clock management a bit and thus touches a bunch of lines.

  All in all, a bit more changes than we'd like at this point, but
  nothing stands out as risky either so it seems like the right thing to
  send it up now instead of holding it to the merge window"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  drivers/soc: qcom: do not disable the iface clock in probe
  ARM: imx: fix .is_enabled() of shared gate clock
  ARM: OMAP3: Fix I/O chain clock line assertion timed out error
  ARM: keystone: dts: fix bindings for pcie and usb clock nodes
  bus: omap_l3_noc: Fix connID for OMAP4
  ARM: DT: imx53: fix lvds channel 1 port
  ARM: dts: cm-t54: fix serial console power supply.
  ARM: dts: dra7-evm: Fix NAND GPMC timings
  ARM: pxa: fix section mismatch warning for pxa_timer_nodt_init
  ARM: OMAP: Fix Kconfig warning for omap1

Pull MIPS fixes from Ralf Baechle:
 "The final round of fixes.  One corner case in the math emulator and
  another one in the mcount function for ftrace"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: mcount: Adjust stack pointer for static trace in MIPS32
  MIPS: Fix MFC1 & MFHC1 emulation for 64-bit MIPS systems

Pull x86 fixes from Ingo Molnar:
 "This has:

   - EFI revert to fix a boot regression
   - early_ioremap() fix for boot failure
   - KASLR fix for possible boot failures
   - EFI fix for corrupted string printing
   - remove a misleading EFI bootup 'failed!' error message

  Unfortunately it's all rather close to the merge window"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Truncate 64-bit values when calling 32-bit OutputString()
  x86/efi: Delete misleading efi_printk() error message
  Revert "efi/x86: efistub: Move shared dependencies to <asm/efi.h>"
  x86/kaslr: Avoid the setup_data area when picking location
  x86 early_ioremap: Increase FIX_BTMAPS_SLOTS to 8

Only exchange source and destination filenames
if flags contain RENAME_EXCHANGE.
In case if executable file was running and replaced by
other file /proc/PID/exe should still show correct file name,
not the old name of the file by which it was replaced.

The scenario when this bug manifests itself was like this:
* ALT Linux uses rpm and start-stop-daemon;
* during a package upgrade rpm creates a temporary file
  for an executable to rename it upon successful unpacking;
* start-stop-daemon is run subsequently and it obtains
  the (nonexistant) temporary filename via /proc/PID/exe
  thus failing to identify the running process.

Note that "long" filenames (> DNAiME_INLINE_LEN) are still
exchanged without RENAME_EXCHANGE and this behaviour exists
long enough (should be fixed too apparently).
So this patch is just an interim workaround that restores
behavior for "short" names as it was before changes
introduced by commit da1ce067 ("vfs: add cross-rename").

See https://lkml.org/lkml/2014/9/7/6 for details.

AV: the comments about being more careful with ->d_name.hash
than with ->d_name.name are from back in 2.3.40s; they
became obsolete by 2.3.60s, when we started to unhash the
target instead of swapping hash chain positions followed
by d_delete() as we used to do when dcache was first
introduced.
Acked-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: da1ce067 "vfs: add cross-rename"
Signed-off-by: Mikhail Efremov <sem@altlinux.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

and do it along with ->d_name.len there
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... renaming it into dentry_unlock_for_move() and making it more
symmetric with dentry_lock_for_move().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

it folds into __d_move() now
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>