Function pci_enable_msix_exact() is a variation of
pci_enable_msix_range() that allows a device driver
to request a particular number of MSI-X interrupts,
rather than any number within a specified range.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>

bsg currently checks ->request_fn to check whether a queue can
handle struct request. But with blk-mq, we don't have a request_fn
yet are request based. Add a queue_is_rq_based() helper and use
that in bsg, I'm guessing this is not the last place we need to
update for this. Besides, it better explains what is being
checked.
Signed-off-by: Jens Axboe <axboe@fb.com>

Signed-off-by: Jens Axboe <axboe@fb.com>

Since we are now, by default, applying timer slack to expiry times,
the logic for when to modify a timer in the block code is suboptimal.
The block layer keeps a forward rolling timer per queue for all
requests, and modifies this timer if a request has a shorter timeout
than what the current expiry time is. However, this breaks down
when our rounded timer values get applied slack. Then each new
request ends up modifying the timer, since we're still a little
in front of the timer + slack.

Fix this by allowing a tolerance of HZ / 2, the timeout handling
doesn't need to be very precise. This drastically cuts down
the number of timer modifications we have to make.
Signed-off-by: Jens Axboe <axboe@fb.com>

This allows to mirror the blk-mq code flow for more a more readable I/O
completion handler in SCSI.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

We will use this work_struct to requeue scsi commands from the
completion handler as well, so give it a more generic name.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

This allows to requeue a request that has been accepted by ->queue_rq
earlier.  This is needed by the SCSI layer in various error conditions.

The existing internal blk_mq_requeue_request is renamed to
__blk_mq_requeue_request as it is a lower level building block for this
funtionality.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Add a helper to unconditionally kick contexts of a queue.  This will
be needed by the SCSI layer to provide fair queueing between multiple
devices on a single host.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Add a blk-mq equivalent to blk_delay_queue so that the scsi layer can ask
to be kicked again after a delay.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Modified by me to kill the unnecessary preempt disable/enable
in the delayed workqueue handler.
Signed-off-by: Jens Axboe <axboe@fb.com>

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Add two unlinkely branches to make sure the resid is initialized correctly
for bidi request pairs, and the second request gets properly freed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Split out the bottom half of blk_mq_end_io so that drivers can perform
work when they know a request has been completed, but before it has been
freed.  This also obsoletes blk_mq_end_io_partial as drivers can now
pass any value to blk_update_request directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

blk_mq_work_fn() is always invoked off the bounded workqueues,
so it can happily preempt among the queues in that set without
causing any issues for blk-mq.
Signed-off-by: Jens Axboe <axboe@fb.com>

UP or CONFIG_PREEMPT_NONE will return 0, and what we really
want to check is whether or not we are on the right CPU.
So don't make PREEMPT part of this, just test the CPU in
the mask directly.
Signed-off-by: Jens Axboe <axboe@fb.com>

The friendly Intel kbuild test robot reported:

drivers/cdrom/gdrom.c: In function 'gdrom_readdisk_dma':
drivers/cdrom/gdrom.c:605:3: error: 'struct request' has no member named 'buffer'

Convert that from req->buffer to bio_data(rq->bio). Apparently
my grep missed this one, and I don't build for Sega Dreamcast
enough.
Signed-off-by: Jens Axboe <axboe@fb.com>

Instead of setting the REQ_QUEUED flag on each of them just take it into
account in the only macro checking it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Add a new blk_mq_tag_set structure that gets set up before we initialize
the queue.  A single blk_mq_tag_set structure can be shared by multiple
queues.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Modular export of blk_mq_{alloc,free}_tagset added by me.
Signed-off-by: Jens Axboe <axboe@fb.com>

If we want to share tag and request allocation between queues we cannot
initialize the request at init/free time, but need to initialize it
at allocation time as it might get used for different queues over its
lifetime.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

The current blk_mq_init_commands/blk_mq_free_commands interface has a
two problems:

 1) Because only the constructor is passed to blk_mq_init_commands there
    is no easy way to clean up when a comman initialization failed.  The
    current code simply leaks the allocations done in the constructor.

 2) There is no good place to call blk_mq_free_commands: before
    blk_cleanup_queue there is no guarantee that all outstanding
    commands have completed, so we can't free them yet.  After
    blk_cleanup_queue the queue has usually been freed.  This can be
    worked around by grabbing an unconditional reference before calling
    blk_cleanup_queue and dropping it after blk_mq_free_commands is
    done, although that's not exatly pretty and driver writers are
    guaranteed to get it wrong sooner or later.

Both issues are easily fixed by making the request constructor and
destructor normal blk_mq_ops methods.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Drivers shouldn't have to care about the block layer setting aside a
request to implement the flush state machine.  We already override the
mq context and tag to make it more transparent, but so far haven't deal
with the driver private data in the request.  Make sure to override this
as well, and while we're at it add a proper helper sitting in blk-mq.c
that implements the full impersonation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Drivers can reach their private data easily using the blk_mq_rq_to_pdu
helper and don't need req->special.  By not initializing it code can
be simplified nicely, and we also shave off a few more instructions from
the I/O path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.

Convert old style drivers to just use bio_data().

For the discard payload use case, just reference the page
in the bio.
Signed-off-by: Jens Axboe <axboe@fb.com>

We don't like this, but things have diverged with the blk-mq fixes
in 3.15-rc1. So merge it in.

Some versions of gcc even warn about it:

  mm/shmem.c: In function ‘shmem_file_aio_read’:
  mm/shmem.c:1414: warning: ‘error’ may be used uninitialized in this function

If the loop is aborted during the first iteration by one of the two
first break statements, error will be uninitialized.

Introduced by commit 6e58e79d ("introduce copy_page_to_iter, kill
loop over iovec in generic_file_aio_read()").
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On 32 bit, size_t is "unsigned int", not "unsigned long", causing the
following warning when comparing with PAGE_SIZE, which is always "unsigned
long":

  fs/cifs/file.c: In function ‘cifs_readdata_to_iov’:
  fs/cifs/file.c:2757: warning: comparison of distinct pointer types lacks a cast

Introduced by commit 7f25bba8 ("cifs_iovec_read: keep iov_iter
between the calls of cifs_readdata_to_iov()"), which changed the
signedness of "remaining" and the code from min_t() to min().
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull slab changes from Pekka Enberg:
 "The biggest change is byte-sized freelist indices which reduces slab
  freelist memory usage:

    https://lkml.org/lkml/2013/12/2/64"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm: slab/slub: use page->list consistently instead of page->lru
  mm/slab.c: cleanup outdated comments and unify variables naming
  slab: fix wrongly used macro
  slub: fix high order page allocation problem with __GFP_NOFAIL
  slab: Make allocations with GFP_ZERO slightly more efficient
  slab: make more slab management structure off the slab
  slab: introduce byte sized index for the freelist of a slab
  slab: restrict the number of objects in a slab
  slab: introduce helper functions to get/set free object
  slab: factor out calculate nr objects in cache_estimate

Pull misc kbuild changes from Michal Marek:
 "Here is the non-critical part of kbuild:
   - One bogus coccinelle check removed, one check fixed not to suggest
     the obsolete PTR_RET macro
   - scripts/tags.sh does not index the generated *.mod.c files
   - new objdiff tool to list differences between two versions of an
     object file
   - A fix for scripts/bootgraph.pl"

* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  scripts/coccinelle: Use PTR_ERR_OR_ZERO
  scripts/bootgraph.pl: Add graphic header
  scripts: objdiff: detect object code changes between two commits
  Coccicheck: Remove memcpy to struct assignment test
  scripts/tags.sh: Ignore *.mod.c

This patch fixes I/O errors with the sym53c8xx_2 driver when the disk
returns QUEUE FULL status.

When the controller encounters an error (including QUEUE FULL or BUSY
status), it aborts all not yet submitted requests in the function
sym_dequeue_from_squeue.

This function aborts them with DID_SOFT_ERROR.

If the disk has full tag queue, the request that caused the overflow is
aborted with QUEUE FULL status (and the scsi midlayer properly retries
it until it is accepted by the disk), but the sym53c8xx_2 driver aborts
the following requests with DID_SOFT_ERROR --- for them, the midlayer
does just a few retries and then signals the error up to sd.

The result is that disk returning QUEUE FULL causes request failures.

The error was reproduced on 53c895 with COMPAQ BD03685A24 disk
(rebranded ST336607LC) with command queue 48 or 64 tags.  The disk has
64 tags, but under some access patterns it return QUEUE FULL when there
are less than 64 pending tags.  The SCSI specification allows returning
QUEUE FULL anytime and it is up to the host to retry.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 8f619b54 ("powerpc/ppc64: Do not turn AIL (reloc-on
interrupts) too early") added code to set the AIL bit in the LPCR
without checking whether the kernel is running in hypervisor mode.  The
result is that when the kernel is running as a guest (i.e., under
PowerKVM or PowerVM), the processor takes a privileged instruction
interrupt at that point, causing a panic.  The visible result is that
the kernel hangs after printing "returning from prom_init".

This fixes it by checking for hypervisor mode being available before
setting LPCR.  If we are not in hypervisor mode, we enable relocation-on
interrupts later in pSeries_setup_arch using the H_SET_MODE hcall.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commits 11d4616b ("futex: revert back to the explicit waiter
counting code") and 69cd9eba ("futex: avoid race between requeue and
wake") changed some of the finer details of how we think about futexes.
One was a late fix and the other a consequence of overlooking the whole
requeuing logic.

The first change caused our documentation to be incorrect, and the
second made us aware that we need to explicitly add more details to it.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull yet more networking updates from David Miller:

 1) Various fixes to the new Redpine Signals wireless driver, from
    Fariya Fatima.

 2) L2TP PPP connect code takes PMTU from the wrong socket, fix from
    Dmitry Petukhov.

 3) UFO and TSO packets differ in whether they include the protocol
    header in gso_size, account for that in skb_gso_transport_seglen().
   From Florian Westphal.

 4) If VLAN untagging fails, we double free the SKB in the bridging
    output path.  From Toshiaki Makita.

 5) Several call sites of sk->sk_data_ready() were referencing an SKB
    just added to the socket receive queue in order to calculate the
    second argument via skb->len.  This is dangerous because the moment
    the skb is added to the receive queue it can be consumed in another
    context and freed up.

    It turns out also that none of the sk->sk_data_ready()
    implementations even care about this second argument.

    So just kill it off and thus fix all these use-after-free bugs as a
    side effect.

 6) Fix inverted test in tcp_v6_send_response(), from Lorenzo Colitti.

 7) pktgen needs to do locking properly for LLTX devices, from Daniel
    Borkmann.

 8) xen-netfront driver initializes TX array entries in RX loop :-) From
    Vincenzo Maffione.

 9) After refactoring, some tunnel drivers allow a tunnel to be
    configured on top itself.  Fix from Nicolas Dichtel.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (46 commits)
  vti: don't allow to add the same tunnel twice
  gre: don't allow to add the same tunnel twice
  drivers: net: xen-netfront: fix array initialization bug
  pktgen: be friendly to LLTX devices
  r8152: check RTL8152_UNPLUG
  net: sun4i-emac: add promiscuous support
  net/apne: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
  net: ipv6: Fix oif in TCP SYN+ACK route lookup.
  drivers: net: cpsw: enable interrupts after napi enable and clearing previous interrupts
  drivers: net: cpsw: discard all packets received when interface is down
  net: Fix use after free by removing length arg from sk_data_ready callbacks.
  Drivers: net: hyperv: Address UDP checksum issues
  Drivers: net: hyperv: Negotiate suitable ndis version for offload support
  Drivers: net: hyperv: Allocate memory for all possible per-pecket information
  bridge: Fix double free and memory leak around br_allowed_ingress
  bonding: Remove debug_fs files when module init fails
  i40evf: program RSS LUT correctly
  i40evf: remove open-coded skb_cow_head
  ixgb: remove open-coded skb_cow_head
  igbvf: remove open-coded skb_cow_head
  ...

Merge tag 'blackfin-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux

Pull blackfin updates from Steven Miao:
 "Code cleanup, some previously ignored patches, and bug fixes"

* tag 'blackfin-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux:
  blackfin: cleanup board files
  bf609: clock: drop unused clock bit set/clear functions
  Blackfin: bf537: rename "CONFIG_ADT75"
  Blackfin: bf537: rename "CONFIG_AD7314"
  Blackfin: bf537: rename ad2s120x ->ad2s1200
  blackfin: bf537: fix typo "CONFIG_SND_SOC_ADV80X_MODULE"
  blackfin: dma: current count mmr is read only
  bfin_crc: Move architecture independant crc header file out of the blackfin folder.
  bf54x: drop unuesd HOST status,control,timeout registers bit define macros
  blackfin: portmux: cleanup head file
  Blackfin: remove "config IP_CHECKSUM_L1"
  blackfin: Remove GENERIC_GPIO config option again
  blackfin:Use generic /proc/interrupts implementation
  blackfin: bf60x: fix typo "CONFIG_PM_BFIN_WAKE_PA15_POL"

Merge tag 'remoteproc-3.15-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/remoteproc

Pull remoteproc cleanups from Ohad Ben-Cohen:
 "Several remoteproc cleanup patches coming from Jingoo Han, Julia
  Lawall and Uwe Kleine-König"

* tag 'remoteproc-3.15-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/remoteproc:
  remoteproc/ste_modem: staticize local symbols
  remoteproc/davinci: simplify use of devm_ioremap_resource
  remoteproc/davinci: drop needless devm_clk_put

Pull llvm patches from Behan Webster:
 "These are some initial updates to support compiling the kernel with
  clang.

  These patches have been through the proper reviews to the best of my
  ability, and have been soaking in linux-next for a few weeks.  These
  patches by themselves still do not completely allow clang to be used
  with the kernel code, but lay the foundation for other patches which
  are still under review.

  Several other of the LLVMLinux patches have been already added via
  maintainer trees"

* tag 'llvmlinux-for-v3.15' of git://git.linuxfoundation.org/llvmlinux/kernel:
  x86: LLVMLinux: Fix "incomplete type const struct x86cpu_device_id"
  x86 kbuild: LLVMLinux: More cc-options added for clang
  x86, acpi: LLVMLinux: Remove nested functions from Thinkpad ACPI
  LLVMLinux: Add support for clang to compiler.h and new compiler-clang.h
  LLVMLinux: Remove warning about returning an uninitialized variable
  kbuild: LLVMLinux: Fix LINUX_COMPILER definition script for compilation with clang
  Documentation: LLVMLinux: Update Documentation/dontdiff
  kbuild: LLVMLinux: Adapt warnings for compilation with clang
  kbuild: LLVMLinux: Add Kbuild support for building kernel with Clang

Pull SCSI target updates from Nicholas Bellinger:
 "Here are the target pending updates for v3.15-rc1.  Apologies in
  advance for waiting until the second to last day of the merge window
  to send these out.

  The highlights this round include:

   - iser-target support for T10 PI (DIF) offloads (Sagi + Or)
   - Fix Task Aborted Status (TAS) handling in target-core (Alex Leung)
   - Pass in transport supported PI at session initialization (Sagi + MKP + nab)
   - Add WRITE_INSERT + READ_STRIP T10 PI support in target-core (nab + Sagi)
   - Fix iscsi-target ERL=2 ASYNC_EVENT connection pointer bug (nab)
   - Fix tcm_fc use-after-free of ft_tpg (Andy Grover)
   - Use correct ib_sg_dma primitives in ib_isert (Mike Marciniszyn)

  Also, note the virtio-scsi + vhost-scsi changes to expose T10 PI
  metadata into KVM guest have been left-out for now, as there where a
  few comments from MST + Paolo that where not able to be addressed in
  time for v3.15.  Please expect this feature for v3.16-rc1"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (43 commits)
  ib_srpt: Use correct ib_sg_dma primitives
  target/tcm_fc: Rename ft_tport_create to ft_tport_get
  target/tcm_fc: Rename ft_{add,del}_lport to {add,del}_wwn
  target/tcm_fc: Rename structs and list members for clarity
  target/tcm_fc: Limit to 1 TPG per wwn
  target/tcm_fc: Don't export ft_lport_list
  target/tcm_fc: Fix use-after-free of ft_tpg
  target: Add check to prevent Abort Task from aborting itself
  target: Enable READ_STRIP emulation in target_complete_ok_work
  target/sbc: Add sbc_dif_read_strip software emulation
  target: Enable WRITE_INSERT emulation in target_execute_cmd
  target/sbc: Add sbc_dif_generate software emulation
  target/sbc: Only expose PI read_cap16 bits when supported by fabric
  target/spc: Only expose PI mode page bits when supported by fabric
  target/spc: Only expose PI inquiry bits when supported by fabric
  target: Pass in transport supported PI at session initialization
  target/iblock: Fix double bioset_integrity_free bug
  Target/sbc: Initialize COMPARE_AND_WRITE write_sg scatterlist
  target/rd: T10-Dif: RAM disk is allocating more space than required.
  iscsi-target: Fix ERL=2 ASYNC_EVENT connection pointer bug
  ...

Pull media fixes from Mauro Carvalho Chehab:
 "A series of bug fix patches for v3.15-rc1.  Most are just driver
  fixes.  There are some changes at remote controller core level, fixing
  some definitions on a new API added for Kernel v3.15.

  It also adds the missing include at include/uapi/linux/v4l2-common.h,
  to allow its compilation on userspace, as pointed by you"

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (24 commits)
  [media] gpsca: remove the risk of a division by zero
  [media] stk1160: warrant a NUL terminated string
  [media] v4l: ti-vpe: retain v4l2_buffer flags for captured buffers
  [media] v4l: ti-vpe: Set correct field parameter for output and capture buffers
  [media] v4l: ti-vpe: zero out reserved fields in try_fmt
  [media] v4l: ti-vpe: Fix initial configuration queue data
  [media] v4l: ti-vpe: Use correct bus_info name for the device in querycap
  [media] v4l: ti-vpe: report correct capabilities in querycap
  [media] v4l: ti-vpe: Allow usage of smaller images
  [media] v4l: ti-vpe: Use video_device_release_empty
  [media] v4l: ti-vpe: Make sure in job_ready that we have the needed number of dst_bufs
  [media] lgdt3305: include sleep functionality in lgdt3304_ops
  [media] drx-j: use customise option correctly
  [media] m88rs2000: fix sparse static warnings
  [media] r820t: fix size and init values
  [media] rc-core: remove generic scancode filter
  [media] rc-core: split dev->s_filter
  [media] rc-core: do not change 32bit NEC scancode format for now
  [media] rtl28xxu: remove duplicate ID 0458:707f Genius TVGo DVB-T03
  [media] xc2028: add missing break to switch
  ...

Pull PCIe non-transparent bridge fixes and features from Jon Mason:
 "NTB driver bug fixes to address issues in list traversal, skb leak in
  ntb_netdev, a typo, and a leak of msix entries in the error path.
  Clean ups of the event handling logic, as well as a overall style
  cleanup.  Finally, the driver was converted to use the new
  pci_enable_msix_range logic (and the refactoring to go along with it)"

* tag 'ntb-3.15' of git://github.com/jonmason/ntb:
  ntb: Use pci_enable_msix_range() instead of pci_enable_msix()
  ntb: Split ntb_setup_msix() into separate BWD/SNB routines
  ntb: Use pci_msix_vec_count() to obtain number of MSI-Xs
  NTB: Code Style Clean-up
  NTB: client event cleanup
  ntb: Fix leakage of ntb_device::msix_entries[] array
  NTB: Fix typo in setting one translation register
  ntb_netdev: Fix skb free issue in open
  ntb_netdev: Fix list_for_each_entry exit issue

The vfs merge caused a latent bug to show up:

   In file included from fs/ceph/super.h:4:0,
                    from fs/ceph/ioctl.c:3:
   include/linux/ceph/ceph_debug.h:4:0: warning: "pr_fmt" redefined [enabled by default]
    #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
    ^
   In file included from include/linux/kernel.h:13:0,
                    from include/linux/uio.h:12,
                    from include/linux/socket.h:7,
                    from include/uapi/linux/in.h:22,
                    from include/linux/in.h:23,
                    from fs/ceph/ioctl.c:1:
   include/linux/printk.h:214:0: note: this is the location of the previous definition
    #define pr_fmt(fmt) fmt
    ^

where the reason is that <linux/ceph_debug.h> is included much too late
for the "pr_fmt()" define.

The include of <linux/ceph_debug.h> needs to be the first include in the
file, but fs/ceph/ioctl.c had for some reason missed that, and it wasn't
noticeable until some unrelated header file changes brought in an
indirect earlier include of <linux/kernel.h>.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>