To increase compiler portability there is <linux/compiler.h> which
provides convenience macros for various gcc constructs.  Eg: __weak for
__attribute__((weak)).  I've replaced all instances of gcc attributes
with the right macro in the kernel subsystem.
Signed-off-by: NGideon Israel Dsouza <gidisrael@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since the software suspend extents are organized in an rbtree, use rb_entry
instead of container_of, as it is semantically more appropriate in order to
get a node as it is iterated.
Signed-off-by: NDavidlohr Bueso <dave@gnu.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

With the introduction of suspend to both into in-kernel hibernation
code, dmesg was getting polluted with backspace characters printed as
part of image saving progress indicator. This patch introduces printing
of progress indicator on image save/load every 10% and one line at a
time. As an additional benefit, all other messages emitted by the kernel
during hibernation/thaw should now print cleanly as well.
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

It is often useful to suspend to memory after hibernation image has been
written to disk. If the battery runs out or power is otherwise lost, the
computer will resume from the hibernated image. If not, it will resume
from memory and hibernation image will be discarded.
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

 1. Do not allocate memory for buffers from emergency pools, unless
    absolutely required. Do not warn about and do not retry non-essential
    failed allocations.

 2. Do not check the amount of free pages left on every single page
    write, but wait until one map is completely populated and then check.

 3. Set maximum number of pages for read buffering consistently, instead
    of inadvertently depending on the size of the sector type.

 4. Fix copyright line, which I missed when I submitted the hibernation
    threading patch.

 5. Dispense with bit shifting arithmetic to improve readability.

 6. Really recalculate the number of pages required to be free after all
    allocations have been done.

 7. Fix calculation of pages required for read buffering. Only count in
    pages that do not belong to high memory.
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Hibernation regression fix, since 3.2.

Calculate the number of required free pages based on non-high memory
pages only, because that is where the buffers will come from.

Commit 081a9d04 introduced a new buffer
page allocation logic during hibernation, in order to improve the
performance. The amount of pages allocated was calculated based on total
amount of pages available, although only non-high memory pages are
usable for this purpose. This caused hibernation code to attempt to over
allocate pages on platforms that have high memory, which led to hangs.
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@suse.de>

For compressed image, the space required is not known until
we finish compressing and writing all pages.
This patch drops the check, and if swap space is not enough
finally, system can still restore to normal after writing
swap fails for compressed images.
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Move invalidate_bdev, block_sync_page into fs/block_dev.c.  Export
kill_bdev as well, so brd doesn't have to open code it.  Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving.  The small comment replacing it says enough.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Use threads for LZO compression/decompression on hibernate/thaw.
Improve buffering on hibernate/thaw.
Calculate/verify CRC32 of the image pages on hibernate/thaw.

In my testing, this improved write/read speed by a factor of about two.
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Commit 3624eb04 (PM / Hibernate: Modify signature used to mark swap)
attempted to modify hibernate signature used to mark swap partitions
containing hibernation images, so that old kernels don't try to
handle compressed images.  However, this change broke resume from
hibernation on Fedora 14 that apparently doesn't pass the resume=
argument to the kernel and tries to trigger resume from early user
space.  This doesn't work, because the signature is now different,
so the old signature has to be restored to avoid the problem.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=22732 .
Reported-by: NDr. David Alan Gilbert <linux@treblig.org>
Reported-by: NZhang Rui <rui.zhang@intel.com>
Reported-by: NPascal Chapperon <pascal.chapperon@wanadoo.fr>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

This is a fix for reading LZO compressed image using async I/O.
Essentially, instead of having just one page into which we keep
reading blocks from swap, we allocate enough of them to cover the
largest compressed size and then let block I/O pick them all up. Once
we have them all (and here we wait), we decompress them, as usual.
Obviously, the very first block we still pick up synchronously,
because we need to know the size of the lot before we pick up the
rest.

Also fixed the copyright line, which I've forgotten before.
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().

blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.

All users are converted.  Most conversions are mechanical and don't
introduce any behavior difference.  There are several exceptions.

* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
  reason to OR it explicitly on blkdev_put().

* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
  sb->s_mode.

* With the above changes, sb->s_mode now always should contain
  FMODE_EXCL.  WARN_ON_ONCE() added to kill_block_super() to detect
  errors.

The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>

Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.

* blkdev_get/put() are the primary open and close functions.

* bd_claim/release() deal with exclusive open.

* open/close_bdev_exclusive() are combination of open and claim and
  the other way around, respectively.

* bd_link/unlink_disk_holder() to create and remove holder/slave
  symlinks.

* open_by_devnum() wraps bdget() + blkdev_get().

The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access.  Reorganize the interface such that,

* blkdev_get() is extended to include exclusive access management.
  @holder argument is added and, if is @FMODE_EXCL specified, it will
  gain exclusive access atomically w.r.t. other exclusive accesses.

* blkdev_put() is similarly extended.  It now takes @mode argument and
  if @FMODE_EXCL is set, it releases an exclusive access.  Also, when
  the last exclusive claim is released, the holder/slave symlinks are
  removed automatically.

* bd_claim/release() and close_bdev_exclusive() are no longer
  necessary and either made static or removed.

* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
  is no longer necessary and removed.

* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
  and blkdev_get().  It also has an unexpected extra bdev_read_only()
  test which probably should be moved into blkdev_get().

* open_by_devnum() is modified to take @holder argument and pass it to
  blkdev_get().

Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should).  This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.

open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features.  Well, let's leave them for another day.

Most conversions are straight-forward.  drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NNeil Brown <neilb@suse.de>
Acked-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: NMike Snitzer <snitzer@redhat.com>
Acked-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen <leochen@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Joern Engel <joern@logfs.org>
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>

"gadget", "through", "command", "maintain", "maintain", "controller", "address",
"between", "initiali[zs]e", "instead", "function", "select", "already",
"equal", "access", "management", "hierarchy", "registration", "interest",
"relative", "memory", "offset", "already",
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

After all that's what they are intended for.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since we are adding compression to the kernel's hibernate code,
change signature used by it to mark swap spaces, so that earlier
kernels don't attempt to restore compressed images they cannot
handle.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@ucw.cz>

The hibernate resume code checks if there is an image to resume from
on every boot and, if the kernel is built with CONFIG_PM_DEBUG set
and the image is not present, it prints some scary messages
suggesting there was a boot error of some sort.  Apparently, some
users are confused by them, so make them look less scary and adjust
the other hibernate resume debug messages to match them.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Compress hibernation image with LZO in order to save on I/O and
therefore time to hibernate/thaw.

[rjw: Added hibernate=nocompress command line option instead of just
 nocompress which would be confusing, fixed a couple of compiler
 warnings, fixed kerneldoc comments, minor cleanups.]
Signed-off-by: NBojan Smojver <bojan@rexursive.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Please revert 2.6.36-rc commit d2997b10
"hibernation: freeze swap at hibernation".  It complicated matters by
adding a second swap allocation path, just for hibernation; without in any
way fixing the issue that it was intended to address - page reclaim after
fixing the hibernation image might free swap from a page already imaged as
swapcache, letting its swap be reallocated to store a different page of
the image: resulting in data corruption if the imaged page were freed as
clean then swapped back in.  Pages freed to si->swap_map were still in
danger of being reallocated by the alternative allocation path.

I guess it inadvertently fixed slow SSD swap allocation for hibernation,
as reported by Nigel Cunningham: by missing out the discards that occur on
the usual swap allocation path; but that was unintentional, and needs a
separate fix.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ondrej Zary <linux@rainbow-software.org>
Cc: Andrea Gelmini <andrea.gelmini@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nigel Cunningham <nigel@tuxonice.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When taking a memory snapshot in hibernate_snapshot(), all (directly
called) memory allocations use GFP_ATOMIC.  Hence swap misusage during
hibernation never occurs.

But from a pessimistic point of view, there is no guarantee that no page
allcation has __GFP_WAIT.  It is better to have a global indication "we
enter hibernation, don't use swap!".

This patch tries to freeze new-swap-allocation during hibernation.  (All
user processes are frozenm so swapin is not a concern).

This way, no updates will happen to swap_map[] between
hibernate_snapshot() and save_image().  Swap is thawed when swsusp_free()
is called.  We can be assured that swap corruption will not occur.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ondrej Zary <linux@rainbow-software.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pavel@suse.cz no longer works, replace it with working address.
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

There are a few typos in kernel/power/swap.c.  Fix them.
Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Move all the swap processing into one function. It will make swap
calls from a non-swap code easier.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

The first sector knowledge is swap-only specific. Move it into the
swap handle. This will be needed for later non-swap specific code
moving into snapshot.c.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: N"Rafael J. Wysocki" <rjw@sisk.pl>

Move block I/O operations to a separate file. It is because it will
be used later not only by the swap writer.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Remove support of reads with offset. This means snapshot_read/write_next
now does not accept count parameter. It allows to clean up the functions
and snapshot handle which no longer needs to care about offsets.

/dev/snapshot handler is converted to simple_{read_from,write_to}_buffer
which take care of offsets.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

It will never reach here if the sws_resume_bdev is erratic.
swsusp_read() is called only from software_resume(), but after
swsusp_check() which would catch the error state.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Use KERN_CONT in save_image() for printks, so that anybody won't
try to add a loglevel.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Move hibernation code's functions for allocating and freeing swap
from swsusp.c to swap.c, which is where you'd expect to find them.
Signed-off-by: NNigel Cunningham <nigel@tuxonice.net>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Finish a line by \n when load_image fails in the middle of loading.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

There are too many retval variables in save_image(). Thus error return
value from snapshot_read_next() may be ignored and only part of the
snapshot (successfully) written.

Remove 'error' variable, invert the condition in the do-while loop
and convert the loop to use only 'ret' variable.

Switch the rest of the function to consider only 'ret'.

Also make sure we end printed line by \n if an error occurs.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

While cruising through the swsusp code I found few blkdev reference
leaks of resume_bdev.

swsusp_read: remove blkdev_put altogether. Some fail paths do
             not do that.
swsusp_check: make sure we always put a reference on fail paths
software_resume: all fail paths between swsusp_check and swsusp_read
                 omit swsusp_close. Add it in those cases. And since
                 swsusp_read doesn't drop the reference anymore, do
                 it here unconditionally.

[rjw: Fixed a small coding style issue.]
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

* remove asm/atomic.h inclusion from linux/utsname.h --
   not needed after kref conversion
 * remove linux/utsname.h inclusion from files which do not need it

NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however
due to some personality stuff it _is_ needed -- cowardly leave ELF-related
headers and files alone.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove code handling bio_alloc failure with __GFP_WAIT.
Signed-off-by: NNikanth Karthikesan <knikanth@suse.de>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

We can't OR shift values, so get rid of BIO_RW_SYNC and use BIO_RW_SYNCIO
and BIO_RW_UNPLUG explicitly. This brings back the behaviour from before
213d9417.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

it had been put there to mark the call of blkdev_put() that
needed proper argument propagated to it; later patch in the
same series had done just that.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* get rid of fake struct file/struct dentry in __blkdev_get()
* merge __blkdev_get() and do_open()
* get rid of flags argument of blkdev_get()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>