ceph: tolerate (and warn on) extraneous dentry from mds

If the MDS gives us a dentry and we weren't prepared to handle it,
WARN_ON_ONCE instead of crashing.

Reported-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
libceph: avoid truncation due to racing banners

Because the Ceph client messenger uses a non-blocking connect, it is
possible for the sending of the client banner to race with the
arrival of the banner sent by the peer.

When ceph_sock_state_change() notices the connect has completed, it
schedules work to process the socket via con_work().  During this
time the peer is writing its banner, and arrival of the peer banner
races with con_work().

If con_work() calls try_read() before the peer banner arrives, there
is nothing for it to do, after which con_work() calls try_write() to
send the client's banner.  In this case Ceph's protocol negotiation
can complete succesfully.

The server-side messenger immediately sends its banner and addresses
after accepting a connect request, *before* actually attempting to
read or verify the banner from the client.  As a result, it is
possible for the banner from the server to arrive before con_work()
calls try_read().  If that happens, try_read() will read the banner
and prepare protocol negotiation info via prepare_write_connect().
prepare_write_connect() calls con_out_kvec_reset(), which discards
the as-yet-unsent client banner.  Next, con_work() calls
try_write(), which sends the protocol negotiation info rather than
the banner that the peer is expecting.

The result is that the peer sees an invalid banner, and the client
reports "negotiation failed".

Fix this by moving con_out_kvec_reset() out of
prepare_write_connect() to its callers at all locations except the
one where the banner might still need to be sent.

[elder@inktak.com: added note about server-side behavior]

Signed-off-by: Jim Schutt <jaschut@sandia.gov>
Reviewed-by: Alex Elder <elder@inktank.com>
ceph: avoid divide by zero in __validate_layout()

If "l->stripe_unit" is zero the the mod on the next line will cause a
divide by zero bug.  This comes from the copy_from_user() in
ceph_ioctl_set_layout_policy().  Passing 0 is valid, though (it means
"do not change") so avoid the % check in that case.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Merge branch 'drm-fixes-3.6' of git://people.freedesktop.org/~agd5f/linux into drm-fixes

Alex writes:

"This is the current set of radeon fixes for 3.6.  Nothing too major.

Highlights:
- fix vbios fetch on pure uefi systems
- fix vbios fetch on thunderbolt systems
- MSAA fixes
- lockup timeout fix
- modesetting fix"

* 'drm-fixes-3.6' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon/ss: use num_crtc rather than hardcoded 6
  Revert "drm/radeon: fix bo creation retry path"
  drm/radeon: split ATRM support out from the ATPX handler (v3)
  drm/radeon: convert radeon vfct code to use acpi_get_table_with_size
  ACPI: export symbol acpi_get_table_with_size
  drm/radeon: implement ACPI VFCT vbios fetch (v3)
  drm/radeon/kms: extend the Fujitsu D3003-S2 board connector quirk to cover later silicon stepping
  drm/radeon: fix checking of MSAA renderbuffers on r600-r700
  drm/radeon: allow CMASK and FMASK in the CS checker on r600-r700
  drm/radeon: init lockup timeout on ring init
  drm/radeon: avoid turning off spread spectrum for used pll
Merge branch 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel into drm-fixes

Daniel writes:

" Nothing too major:
- A few fixes around the edid handling from Jani, also fixing a regression
  in 3.5 due to us using gmbus by default.
- Fixup hsw uncached pte flags.
- Fix suspend/resume crash when using hw contexts, from Ben.
- Try to tune gpu turbo a bit better, seems to help with some oddball
  power regressions."

* 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel:
  drm/i915: use hsw rps tuning values everywhere on gen6+
  drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads
  drm/i915: extract connector update from intel_ddc_get_modes() for reuse
  drm/i915: fix hsw uncached pte
  drm/i915/contexts: fix list corruption
  drm/i915: fix EDID memory leak in SDVO
drm: stop vmgfx driver explosion

If you do a page flip with no flags set then event is NULL. If event is
NULL then the vmw_gfx driver likes to go digging into NULL and extracts
NULL->base.file_priv.

On a modern kernel with NULL mapping protection it's just another oops,
without it there are some "intriguing" possibilities.

What it should do is an open question but that for the driver owners to
sort out.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm: Remove two unused fields from struct drm_display_mode

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm/udl: dpms off the crtc when disabled.

This turns off the crtc when its been disabled,
fixes it not turning off properly the whole time.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
drm: Add missing static storage class specifiers in drm_proc.c file

Fixes the following sparse warning:
drivers/gpu/drm/drm_proc.c:92:5:
warning: symbol 'drm_proc_create_files' was not declared. Should it be static?
drivers/gpu/drm/drm_proc.c:175:5:
warning: symbol 'drm_proc_remove_files' was not declared. Should it be static?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
PCI/PM: Enable D3/D3cold by default for most devices

This patch fixes the following bug:

http://marc.info/?l=linux-usb&m=134318961120825&w=2

Originally, device lower power states include D1, D2, D3.  After that,
D3 is further divided into D3hot and D3cold.  To support both scenario
safely, original D3 is mapped to D3cold.

When adding D3cold support, because worry about some device may have
broken D3cold support, D3cold is disabled by default.  This disable D3
on original platform too.  But some original platform may only have
working D3, but no working D1, D2.  The root cause of the above bug is
it too.

To deal with this, this patch enables D3/D3cold by default for most
devices.  This restores the original behavior.  For some devices that
suspected to have broken D3cold support, such as PCIe port, D3cold is
disabled by default.

Reported-by: Bjorn Mork <bjorn@mork.no>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
PCI/PM: Keep parent bridge active when probing device

This patch fixes the following bug:

http://marc.info/?l=linux-pci&m=134329923124234&w=2

The root cause of the bug is as follow.

If a device is not bound with the corresponding driver, the device
runtime PM will be disabled and the device will be put into suspended
state.  So that, the bridge/PCIe port connected to it may be put into
suspended and low power state.  When do probing for the device later,
because the bridge/PCIe port connected to it is in low power state,
the IO access to device may fail.

To solve the issue, the bridge/PCIe port connected to the device is
put into active state before probing.

Reported-by: Bjorn Mork <bjorn@mork.no>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
PCI/PM: Fix config reg access for D3cold and bridge suspending

This patch fixes the following bug:

http://marc.info/?l=linux-pci&m=134338059022620&w=2

Where lspci does not work properly if a device and the corresponding
parent bridge (such as PCIe port) is suspended.  This is because the
device configuration space registers will be not accessible if the
corresponding parent bridge is suspended or the device is put into
D3cold state.

To solve the issue, the bridge/PCIe port connected to the device is
put into active state before read/write configuration space registers.
If the device is in D3cold state, it will be put into active state
too.

To avoid resume/suspend PCIe port for each configuration register
read/write, a small delay is added before the PCIe port to go
suspended.

Reported-by: Bjorn Mork <bjorn@mork.no>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
PCI/PM: Add ABI document for sysfs file d3cold_allowed

This patch adds ABI document for the following sysfs file:

/sys/bus/pci/devices/.../d3cold_allowed

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
cs5535-clockevt: typo, it's MFGPT, not MFPGT

Signed-off-by: Jens Rottmann <JRottmann@LiPPERTEmbedded.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: change nr_ptes BUG_ON to WARN_ON

Occasionally an isolated BUG_ON(mm->nr_ptes) gets reported, indicating
that not all the page tables allocated could be found and freed when
exit_mmap() tore down the user address space.

There's usually nothing we can say about it, beyond that it's probably a
sign of some bad memory or memory corruption; though it might still
indicate a bug in vma or page table management (and did recently reveal a
race in THP, fixed a few months ago).

But one overdue change we can make is from BUG_ON to WARN_ON.

It's fairly likely that the system will crash shortly afterwards in some
other way (for example, the BUG_ON(page_mapped(page)) in
__delete_from_page_cache(), once an inode mapped into the lost page tables
gets evicted); but might tell us more before that.

Change the BUG_ON(page_mapped) to WARN_ON too?  Later perhaps: I'm less
eager, since that one has several times led to fixes.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation: update mount option in filesystem/vfat.txt

Update two mount options(discard, nfs) in vfat.txt.

Signed-off-by: Namjae Jeon <linkinjeon@gmail.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>
cciss: fix incorrect scsi status reporting

Delete code which sets SCSI status incorrectly as it's already been set
correctly above this incorrect code.  The bug was introduced in 2009 by
commit b0e15f6db111 ("cciss: fix typo that causes scsi status to be
lost.")

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Reported-by: Roel van Meer <roel.vanmeer@bokxing.nl>
Tested-by: Roel van Meer <roel.vanmeer@bokxing.nl>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: hugetlbfs: correctly populate shared pmd

Each page mapped in a process's address space must be correctly
accounted for in _mapcount.  Normally the rules for this are
straightforward but hugetlbfs page table sharing is different.  The page
table pages at the PMD level are reference counted while the mapcount
remains the same.

If this accounting is wrong, it causes bugs like this one reported by
Larry Woodman:

  kernel BUG at mm/filemap.c:135!
  invalid opcode: 0000 [#1] SMP
  CPU 22
  Modules linked in: bridge stp llc sunrpc binfmt_misc dcdbas microcode pcspkr acpi_pad acpi]
  Pid: 18001, comm: mpitest Tainted: G        W    3.3.0+ #4 Dell Inc. PowerEdge R620/07NDJ2
  RIP: 0010:[<ffffffff8112cfed>]  [<ffffffff8112cfed>] __delete_from_page_cache+0x15d/0x170
  Process mpitest (pid: 18001, threadinfo ffff880428972000, task ffff880428b5cc20)
  Call Trace:
    delete_from_page_cache+0x40/0x80
    truncate_hugepages+0x115/0x1f0
    hugetlbfs_evict_inode+0x18/0x30
    evict+0x9f/0x1b0
    iput_final+0xe3/0x1e0
    iput+0x3e/0x50
    d_kill+0xf8/0x110
    dput+0xe2/0x1b0
    __fput+0x162/0x240

During fork(), copy_hugetlb_page_range() detects if huge_pte_alloc()
shared page tables with the check dst_pte == src_pte.  The logic is if
the PMD page is the same, they must be shared.  This assumes that the
sharing is between the parent and child.  However, if the sharing is
with a different process entirely then this check fails as in this
diagram:

  parent
    |
    ------------>pmd
                 src_pte----------> data page
                                        ^
  other--------->pmd--------------------|
                  ^
  child-----------|
                 dst_pte

For this situation to occur, it must be possible for Parent and Other to
have faulted and failed to share page tables with each other.  This is
possible due to the following style of race.

  PROC A                                          PROC B
  copy_hugetlb_page_range                         copy_hugetlb_page_range
    src_pte == huge_pte_offset                      src_pte == huge_pte_offset
    !src_pte so no sharing                          !src_pte so no sharing

  (time passes)

  hugetlb_fault                                   hugetlb_fault
    huge_pte_alloc                                  huge_pte_alloc
      huge_pmd_share                                 huge_pmd_share
        LOCK(i_mmap_mutex)
        find nothing, no sharing
        UNLOCK(i_mmap_mutex)
                                                      LOCK(i_mmap_mutex)
                                                      find nothing, no sharing
                                                      UNLOCK(i_mmap_mutex)
      pmd_alloc                                       pmd_alloc
      LOCK(instantiation_mutex)
      fault
      UNLOCK(instantiation_mutex)
                                                  LOCK(instantiation_mutex)
                                                  fault
                                                  UNLOCK(instantiation_mutex)

These two processes are not poing to the same data page but are not
sharing page tables because the opportunity was missed.  When either
process later forks, the src_pte == dst pte is potentially insufficient.
As the check falls through, the wrong PTE information is copied in
(harmless but wrong) and the mapcount is bumped for a page mapped by a
shared page table leading to the BUG_ON.

This patch addresses the issue by moving pmd_alloc into huge_pmd_share
which guarantees that the shared pud is populated in the same critical
section as pmd.  This also means that huge_pte_offset test in
huge_pmd_share is serialized correctly now which in turn means that the
success of the sharing will be higher as the racing tasks see the pud
and pmd populated together.

Race identified and changelog written mostly by Mel Gorman.

{akpm@linux-foundation.org: attempt to make the huge_pmd_share() comment comprehensible, clean up coding style]
Reported-by: Larry Woodman <lwoodman@redhat.com>
Tested-by: Larry Woodman <lwoodman@redhat.com>
Reviewed-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Ken Chen <kenchen@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Hillf Danton <dhillf@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>
checkpatch: add control statement test to SINGLE_STATEMENT_DO_WHILE_MACRO

Commit b13edf7ff2dd ("checkpatch: add checks for do {} while (0) macro
misuses") added a test that is overly simplistic for single statement
macros.

Macros that start with control tests should be enclosed in a do {} while
(0) loop.

Add the necessary control tests to the check.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Tested-by: Franz Schrober <franzschrober@yahoo.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hugetlb: update hugetlbpage.txt

Commit f0f57b2b1488 ("mm: move hugepage test examples to
tools/testing/selftests/vm") moved map_hugetlb.c, hugepage-shm.c and
hugepage-mmap.c tests into tools/testing/selftests/vm/ directory, but it
didn't update hugetlbpage.txt

Signed-off-by: Zhouping Liu <sanweidaying@gmail.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>