Some time ago Jeff prepared 42daba31 ("uml: stop saving process FP
state") for UML to stop saving the process FP state between task
switches.  The assumption was that since with SKAS0 every guest process
runs inside a host process context the host OS will take care of keeping
the proper FP state.

Unfortunately this is not true for multi-threaded applications, where
all guest threads share a single host process context yet all may use
the FPU on their own.  Although I haven't verified it I suspect things
to be even worse in SKAS3 mode where all guest processes run inside a
single host process.

The patch reintroduces the saving and restoring of the FP context
between task switches.

[richard@nod.at: Ingo posted this patch in 2009, sadly it was never applied
and got lost. Now in 2011 the problem was reported by Gunnar.]
Signed-off-by: NIngo van Lil <inguin@gmx.de>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reported-by: <gunnarlindroth@hotmail.com>
Tested-by: <gunnarlindroth@hotmail.com>
Cc: Stanislav Meduna <stano@meduna.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I could use out_close1, but that seems to be the code path to close the fd
returned by os_create_unix_socket, and using it to close the fd returned
by mkstemp might lead to some confusion, so I don't do it.
Signed-off-by: NJonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit b789ef51 ("slub: Add cmpxchg_double_slab()") tests for
cmpxchg_double support in the SLUB code and it breaks UML builds with
SLUB.  Since UML does not support checking for CPU features, disable
CMPXCHG_DOUBLE just like CMPXCHG_LOCAL is disabled for UML.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The vmstat_text array is only defined for CONFIG_SYSFS or CONFIG_PROC_FS,
yet it is referenced for per-node vmstat with CONFIG_NUMA:

	drivers/built-in.o: In function `node_read_vmstat':
	node.c:(.text+0x1106df): undefined reference to `vmstat_text'

Introduced in commit fa25c503 ("mm: per-node vmstat: show proper
vmstats").

Define the array for CONFIG_NUMA as well.

[akpm@linux-foundation.org: remove unneeded ifdefs]
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reported-by: NCong Wang <amwang@redhat.com>
Acked-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When compiling mm/mempolicy.c with struct user copy checks the following
warning is shown:

  In file included from arch/x86/include/asm/uaccess.h:572,
                   from include/linux/uaccess.h:5,
                   from include/linux/highmem.h:7,
                   from include/linux/pagemap.h:10,
                   from include/linux/mempolicy.h:70,
                   from mm/mempolicy.c:68:
  In function `copy_from_user',
      inlined from `compat_sys_get_mempolicy' at mm/mempolicy.c:1415:
  arch/x86/include/asm/uaccess_64.h:64: warning: call to `copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct
    LD      mm/built-in.o

Fix this by passing correct buffer size value.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

commit 9d8cebd4 ("mm: fix mbind vma merge problem") didn't really
fix the mbind vma merge problem due to wrong pgoff value passing to
vma_merge(), which made vma_merge() always return NULL.

Before the patch applied, we are getting a result like:

  addr = 0x7fa58f00c000
  [snip]
  7fa58f00c000-7fa58f00d000 rw-p 00000000 00:00 0
  7fa58f00d000-7fa58f00e000 rw-p 00000000 00:00 0
  7fa58f00e000-7fa58f00f000 rw-p 00000000 00:00 0

here 7fa58f00c000->7fa58f00f000 we get 3 VMAs which are expected to be
merged described as described in commit 9d8cebd4.

Re-testing the patched kernel with the reproducer provided in commit
9d8cebd4, we get the correct result:

  addr = 0x7ffa5aaa2000
  [snip]
  7ffa5aaa2000-7ffa5aaa6000 rw-p 00000000 00:00 0
  7fffd556f000-7fffd5584000 rw-p 00000000 00:00 0                          [stack]
Signed-off-by: NCaspar Zhang <caspar@casparzhang.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* git://bedivere.hansenpartnership.com/git/scsi-rc-fixes-2.6: (25 commits)
  [SCSI] bnx2i: Fixed the endian on TTT for NOP out transmission
  [SCSI] libfc: fix referencing to fc_fcp_pkt from the frame pointer via fr_fsp()
  [SCSI] libfc: block SCSI eh thread for blocked rports
  [SCSI] libfc: fix fc_eh_host_reset
  [SCSI] fcoe: Fix deadlock between fip's recv_work and rtnl
  [SCSI] qla2xxx: Update version number to 8.03.07.07-k.
  [SCSI] qla2xxx: Set the task attributes after memsetting fcp cmnd.
  [SCSI] qla2xxx: Correct inadvertent loop state transitions during port-update handling.
  [SCSI] qla2xxx: Save and restore irq in the response queue interrupt handler.
  [SCSI] qla2xxx: Double check for command completion if abort mailbox command fails.
  [SCSI] qla2xxx: Acquire hardware lock while manipulating dsd list.
  [SCSI] qla2xxx: Fix qla24xx revision check while enabling interrupts.
  [SCSI] qla2xxx: T10 DIF - Fix incorrect error reporting.
  [SCSI] qla2xxx: T10 DIF - Handle uninitalized sectors.
  [SCSI] hpsa: fix physical device lun and target numbering problem
  [SCSI] hpsa: fix problem that OBDR devices are not detected
  [SCSI] isci: add version number
  [SCSI] isci: fix event-get pointer increment
  [SCSI] isci: dynamic interrupt coalescing
  [SCSI] isci: Leave requests alone if already terminating.
  ...

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: fix a use after free in xfs_end_io_direct_write

We used to get the victim pinned by dentry_unhash() prior to commit
64252c75 ("vfs: remove dget() from dentry_unhash()") and ->rmdir()
and ->rename() instances relied on that; most of them don't care, but
ones that used d_delete() themselves do.  As the result, we are getting
rmdir() oopses on NFS now.

Just grab the reference before locking the victim and drop it explicitly
after unlocking, same as vfs_rename_other() does.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Tested-by: NSimon Kirby <sim@hostway.ca>
Cc: stable@kernel.org (3.0.x)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a window in which the ioend that we call inode_dio_wake on
in xfs_end_io_direct_write is already free.  Fix this by storing
the inode pointer in a local variable.

This is a fix for the regression introduced in 3.1-rc by
"fs: move inode_dio_done to the end_io handler".
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAlex Elder <aelder@sgi.com>

Include <linux/cryptohash.h> to pickup the declarations for sha_transform
and sha_init to quite the sparse noise:

  warning: symbol 'sha_transform' was not declared. Should it be static?
  warning: symbol 'sha_init' was not declared. Should it be static?
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NMandeep Singh Baines <msb@chromium.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In pcie_find_smpss(), we have the following statement:

 	if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
	    dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))

The problem is that at least on my machine, this gets called for the
root complex (virtual P2P bridge), and dev->bus->self is NULL since
the parent bus for this is not itself anchor to a PCI device.

This adds the necessary NULL check.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NJon Mason <mason@myri.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'acpi' of git://github.com/lenb/linux:
  acpica: ACPI_MAX_SLEEP should be 2 sec, not 20
  ACPI APEI: Add Kconfig option IRQ_WORK for GHES
  PNP: update pnp.debug usage (needs value on command line)
  APEI: Fix WHEA _OSC call

* 'upstream/bugfix' of git://github.com/jsgf/linux-xen:
  xen: use non-tracing preempt in xen_clocksource_read()

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm: Remove duplicate "return" statement
  drm/nv04/crtc: Bail out if FB is not bound to crtc
  drm/nouveau: fix nv04_sgdma_bind on non-"4kB pages" archs
  drm/nouveau: properly handle allocation failure in nouveau_sgdma_populate
  drm/nouveau: fix oops on pre-semaphore hardware
  drm/nv50/crtc: Bail out if FB is not bound to crtc
  drm/radeon/kms: fix DP detect and EDID fetch for DP bridges

* 'fixes' of git://git.linaro.org/people/arnd/arm-soc:
  ARM: CSR: add missing sentinels to of_device_id tables
  ARM: cns3xxx: Fix newly introduced warnings in the PCIe code
  ARM: cns3xxx: Fix compile error caused by hardware.h removed
  ARM: davinci: fix cache flush build error
  ARM: davinci: correct MDSTAT_STATE_MASK
  ARM: davinci: da850 EVM: read mac address from SPI flash
  OMAP: omap_device: fix !CONFIG_SUSPEND case in _noirq handlers
  OMAP2430: hwmod: musb: add missing terminator to omap2430_usbhsotg_addrs[]
  OMAP3: clock: indicate that gpt12_fck and wdt1_fck are in the WKUP clockdomain
  OMAP4: clock: fix compile warning
  OMAP4: clock: re-enable previous clockdomain enable/disable sequence
  OMAP: clockdomain: Wait for powerdomain to be ON when using clockdomain force wakeup
  OMAP: powerdomains: Make all powerdomain target states as ON at init

The LTTng 2.0 kernel tracer (stand-alone module package, available at
http://lttng.org) uses the 0xF6 ioctl range for tracer control and
transport operations.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://github.com/chrismason/linux:
  Btrfs: add dummy extent if dst offset excceeds file end in
  Btrfs: calc file extent num_bytes correctly in file clone
  btrfs: xattr: fix attribute removal
  Btrfs: fix wrong nbytes information of the inode
  Btrfs: fix the file extent gap when doing direct IO
  Btrfs: fix unclosed transaction handle in btrfs_cont_expand
  Btrfs: fix misuse of trans block rsv
  Btrfs: reset to appropriate block rsv after orphan operations
  Btrfs: skip locking if searching the commit root in csum lookup
  btrfs: fix warning in iput for bad-inode
  Btrfs: fix an oops when deleting snapshots

kmemleak is reporting that 32 bytes are being leaked by FUSE:

  unreferenced object 0xe373b270 (size 32):
  comm "fusermount", pid 1207, jiffies 4294707026 (age 2675.187s)
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<b05517d7>] kmemleak_alloc+0x27/0x50
    [<b0196435>] kmem_cache_alloc+0xc5/0x180
    [<b02455be>] fuse_alloc_forget+0x1e/0x20
    [<b0245670>] fuse_alloc_inode+0xb0/0xd0
    [<b01b1a8c>] alloc_inode+0x1c/0x80
    [<b01b290f>] iget5_locked+0x8f/0x1a0
    [<b0246022>] fuse_iget+0x72/0x1a0
    [<b02461da>] fuse_get_root_inode+0x8a/0x90
    [<b02465cf>] fuse_fill_super+0x3ef/0x590
    [<b019e56f>] mount_nodev+0x3f/0x90
    [<b0244e95>] fuse_mount+0x15/0x20
    [<b019d1bc>] mount_fs+0x1c/0xc0
    [<b01b5811>] vfs_kern_mount+0x41/0x90
    [<b01b5af9>] do_kern_mount+0x39/0xd0
    [<b01b7585>] do_mount+0x2e5/0x660
    [<b01b7966>] sys_mount+0x66/0xa0

This leak report is consistent and happens once per boot on
3.1.0-rc5-dirty.

This happens if a FORGET request is queued after the fuse device was
released.
Reported-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Tested-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 37fb3a30 ("fuse: fix flock") added in 3.1-rc4 caused flock() to
fail with ENOSYS with the kernel ABI version 7.16 or earlier.

Fix by falling back to testing FUSE_POSIX_LOCKS for ABI versions 7.16
and earlier.
Reported-by: NMartin Ziegler <ziegler@email.mathematik.uni-freiburg.de>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Tested-by: NMartin Ziegler <ziegler@email.mathematik.uni-freiburg.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'v4l_for_linus' of git://linuxtv.org/mchehab/for_linus:
  [media] vp7045: fix buffer setup
  [media] nuvoton-cir: simplify raw IR sample handling
  [media] [Resend] viacam: Don't explode if pci_find_bus() returns NULL
  [media] v4l2: Fix documentation of the codec device controls
  [media] gspca - sonixj: Fix the darkness of sensor om6802 in 320x240
  [media] gspca - sonixj: Fix wrong register mask for sensor om6802
  [media] gspca - ov519: Fix LED inversion of some ov519 webcams
  [media] pwc: precedence bug in pwc_init_controls()

* 'for-linus' of git://openrisc.net/~jonas/linux:
  Add missing DMA ops
  openrisc: don't use pt_regs in struct sigcontext

You can see there's no file extent with range [0, 4096]. Check this by
btrfsck:

 # btrfsck /dev/sda7
 root 5 inode 258 errors 100
 ...
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

num_bytes should be 4096 not 12288.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

An attribute is not removed by 'setfattr -x attr file' and remains
visible in attr list. This makes xfstests/062 pass again.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

If we write some data into the data hole of the file(no preallocation for this
hole), Btrfs will allocate some disk space, and update nbytes of the inode, but
the other element--disk_i_size needn't be updated. At this condition, we must
update inode metadata though disk_i_size is not changed(btrfs_ordered_update_i_size()
return 1).

 # mkfs.btrfs /dev/sdb1
 # mount /dev/sdb1 /mnt
 # touch /mnt/a
 # truncate -s 856002 /mnt/a
 # dd if=/dev/zero of=/mnt/a bs=4K count=1 conv=nocreat,notrunc
 # umount /mnt
 # btrfsck /dev/sdb1
 root 5 inode 257 errors 400
 found 32768 bytes used err is 1
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When we write some data to the place that is beyond the end of the file
in direct I/O mode, a data hole will be created. And Btrfs should insert
a file extent item that point to this hole into the fs tree. But unfortunately
Btrfs forgets doing it.

The following is a simple way to reproduce it:
 # mkfs.btrfs /dev/sdc2
 # mount /dev/sdc2 /test4
 # touch /test4/a
 # dd if=/dev/zero of=/test4/a seek=8 count=1 bs=4K oflag=direct conv=nocreat,notrunc
 # umount /test4
 # btrfsck /dev/sdc2
 root 5 inode 257 errors 100
Reported-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Tested-by: NTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The function - btrfs_cont_expand() forgot to close the transaction handle before
it jump out the while loop. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

At the beginning of create_pending_snapshot, trans->block_rsv is set
to pending->block_rsv and is used for snapshot things, however, when
it is done, we do not recover it as will.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

While truncating free space cache, we forget to change trans->block_rsv
back to the original one, but leave it with the orphan_block_rsv, and
then with option inode_cache enable, it leads to countless warnings of
btrfs_alloc_free_block and btrfs_orphan_commit_root:

WARNING: at fs/btrfs/extent-tree.c:5711 btrfs_alloc_free_block+0x180/0x350 [btrfs]()
...
WARNING: at fs/btrfs/inode.c:2193 btrfs_orphan_commit_root+0xb0/0xc0 [btrfs]()
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

It's not enough to just search the commit root, since we could be cow'ing the
very block we need to search through, which would mean that its locked and we'll
still deadlock.  So use path->skip_locking as well.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

iput() shouldn't be called for inodes in I_NEW state.
We need to mark inode as constructed first.

WARNING: at fs/inode.c:1309 iput+0x20b/0x210()
Call Trace:
 [<ffffffff8103e7ba>] warn_slowpath_common+0x7a/0xb0
 [<ffffffff8103e805>] warn_slowpath_null+0x15/0x20
 [<ffffffff810eaf0b>] iput+0x20b/0x210
 [<ffffffff811b96fb>] btrfs_iget+0x1eb/0x4a0
 [<ffffffff811c3ad6>] btrfs_run_defrag_inodes+0x136/0x210
 [<ffffffff811ad55f>] cleaner_kthread+0x17f/0x1a0
 [<ffffffff81035b7d>] ? sub_preempt_count+0x9d/0xd0
 [<ffffffff811ad3e0>] ? transaction_kthread+0x280/0x280
 [<ffffffff8105af86>] kthread+0x96/0xa0
 [<ffffffff814336d4>] kernel_thread_helper+0x4/0x10
 [<ffffffff8105aef0>] ? kthread_worker_fn+0x190/0x190
 [<ffffffff814336d0>] ? gs_change+0xb/0xb
Signed-off-by: NSergei Trofimovich <slyfox@gentoo.org>
CC: Konstantin Khlebnikov <khlebnikov@openvz.org>
Tested-by: NDavid Sterba <dsterba@suse.cz>
CC: Josef Bacik <josef@redhat.com>
CC: Chris Mason <chris.mason@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We can reproduce this oops via the following steps:

$ mkfs.btrfs /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs
$ for ((i=0; i<3; i++)); do btrfs sub snap /mnt/btrfs /mnt/btrfs/s_$i; done
$ rm -fr /mnt/btrfs/*
$ rm -fr /mnt/btrfs/*

then we'll get
------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:2264!
[...]
Call Trace:
 [<ffffffffa05578c7>] btrfs_rmdir+0xf7/0x1b0 [btrfs]
 [<ffffffff81150b95>] vfs_rmdir+0xa5/0xf0
 [<ffffffff81153cc3>] do_rmdir+0x123/0x140
 [<ffffffff81145ac7>] ? fput+0x197/0x260
 [<ffffffff810aecff>] ? audit_syscall_entry+0x1bf/0x1f0
 [<ffffffff81153d0d>] sys_unlinkat+0x2d/0x40
 [<ffffffff8147896b>] system_call_fastpath+0x16/0x1b
RIP  [<ffffffffa054f7b9>] btrfs_orphan_add+0x179/0x1a0 [btrfs]

When it comes to btrfs_lookup_dentry, we may set a snapshot's inode->i_ino
to BTRFS_EMPTY_SUBVOL_DIR_OBJECTID instead of BTRFS_FIRST_FREE_OBJECTID,
while the snapshot's location.objectid remains unchanged.

However, btrfs_ino() does not take this into account, and returns a wrong ino,
and causes the oops.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

dvb_usb_device_init calls the frontend_attach method of this driver which
uses vp7045_usb_ob. In order to have a buffer ready in vp7045_usb_op, it has to
be allocated before that happens.

Luckily we can use the whole private data as the buffer as it gets separately
allocated on the heap via kzalloc in dvb_usb_device_init and is thus apt for
use via usb_control_msg.

This fixes a
	BUG: unable to handle kernel paging request at 0000000000001e78

reported by Tino Keitel and diagnosed by Dan Carpenter.

Cc: stable@kernel.org # For v3.0 and upper
Tested-by: NTino Keitel <tino.keitel@tikei.de>
Signed-off-by: NFlorian Mickler <florian@mickler.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

The nuvoton-cir driver was storing up consecutive pulse-pulse and
space-space samples internally, for no good reason, since
ir_raw_event_store_with_filter() already merges back to back like
samples types for us. This should also fix a regression introduced late
in 3.0 that related to a timeout change, which actually becomes correct
when coupled with this change. Tested with RC6 and RC5 on my own
nuvoton-cir hardware atop vanilla 3.0.0, after verifying quirky
behavior in 3.0 due to the timeout change.
Reported-by: NStephan Raue <sraue@openelec.tv>
CC: Stephan Raue <sraue@openelec.tv>
CC: stable@vger.kernel.org
Signed-off-by: NJarod Wilson <jarod@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

In the unlikely case that pci_find_bus() should return NULL
viacam_serial_is_enabled() is going to dereference a NULL pointer and
blow up. Better safe than sorry, so be defensive and check the
pointer.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Acked-by: NJonathan Corbet <corbet@lwn.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>