Commit Graph

244524 Commits

Author SHA1 Message Date
Linus Torvalds
71460af58f Revert "[media] V4L: videobuf, don't use dma addr as physical"
This reverts commit 35d9f510b6.

Quoth Jiri Slaby:
 "It fixes mmap when IOMMU is used on x86 only, but breaks architectures
  like ARM or PPC where virt_to_phys(dma_alloc_coherent) doesn't work.
  We need there dma_mmap_coherent or similar (the trickery what
  snd_pcm_default_mmap does but in some saner way).  But this cannot be
  done at this phase."

Requested-by: Jiri Slaby <jslaby@suse.cz>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-19 10:54:44 -07:00
Linus Torvalds
f28c6179e5 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes:
  GFS2: filesystem hang caused by incorrect lock order
  GFS2: Don't try to deallocate unlinked inodes when mounted ro
  GFS2: directly write blocks past i_size
  GFS2: write_end error path fails to unlock transaction lock
2011-04-19 10:52:51 -07:00
Guenter Roeck
e428d8d3bd hwmon: (max34440) Add driver documentation
MAX34440 and MAX34441 have their own driver, thus there should be explicit
documentation instead of mentioning the chips in the generic PMBus driver
documentation.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
2011-04-19 08:50:00 -07:00
Guenter Roeck
4af33f1726 hwmon: (max16064) Add driver documentation
MAX16064 has its own driver, thus should have its own documentation instead of
being mentioned in the generic PMBus driver documentation.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
2011-04-19 08:49:59 -07:00
Guenter Roeck
2669d9f542 hwmon: (max8688) Add driver documentation
MAX8688 has its own driver, thus should have its own documentation instead of
being mentioned in the generic PMBus driver documentation.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
2011-04-19 08:49:58 -07:00
Guenter Roeck
180b3d889c hwmon: (pmbus) Documentation updates
Fix spelling, correct label name error, and add missing attribute to PMBus
driver documentation.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
2011-04-19 08:49:57 -07:00
Guenter Roeck
c1a76b4741 hwmon: (smm665) Fix spelling error in driver documentation
tempererature may sound interesting, but temperature is still preferred.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
2011-04-19 08:49:57 -07:00
Guenter Roeck
3b17857dfb hwmon: (pmbus) Removed unused variable from struct pmbus_data
struct pmbus_data included an unused variable named status_bits.
Remove it.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
2011-04-19 08:49:56 -07:00
Guenter Roeck
c3a2f0ad49 hwmon: Add submitting-patches checklist to documentation
When writing hardware monitoring drivers, there are some common pitfalls which
keep coming up in code reviews. This patch provides a document describing all
those pitfalls and how to avoid them.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
2011-04-19 08:49:55 -07:00
Takashi Iwai
6981d18437 ALSA: hda - Add a fix-up for Acer dmic with ALC271x codec
Acer laptops with ALC271x needs a magic initialization for digital-mic
to make it working with mono streams (and PulseAudio).
Added a fix-up applied to Acer with ALC271x generically.

Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2011-04-19 16:45:31 +02:00
Jozsef Kadlecsik
a8a8a0937e netfilter: ipset: Fix the order of listing of sets
A restoreable saving of sets requires that list:set type of sets
come last and the code part which should have taken into account
the ordering was broken. The patch fixes the listing order.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-04-19 15:59:15 +02:00
Tao Ma
60735b6362 block: Remove the extra check in queue_requests_store
In queue_requests_store, the code looks like
	if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
		blk_set_queue_full(q, BLK_RW_SYNC);
	} else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
		blk_clear_queue_full(q, BLK_RW_SYNC);
		wake_up(&rl->wait[BLK_RW_SYNC]);
	}
If we don't satify the situation of "if", we can get that
rl->count[BLK_RW_SYNC} < q->nr_quests. It is the same as
rl->count[BLK_RW_SYNC]+1 <= q->nr_requests.
All the "else" should satisfy the "else if" check so it isn't
needed actually.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-19 13:51:53 +02:00
Liu Yuan
ed5302d3c2 block, blk-sysfs: Fix an err return path in blk_register_queue()
We do not call blk_trace_remove_sysfs() in err return path
if kobject_add() fails. This path fixes it.

Cc: stable@kernel.org
Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-19 13:51:53 +02:00
Jens Axboe
d350e6b6e8 block: remove stale kerneldoc member from __blk_run_queue()
We don't pass in a 'force_kblockd' anymore, get rid of the
stsale comment.

Reported-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-19 13:34:14 +02:00
Jens Axboe
c21e6beba8 block: get rid of QUEUE_FLAG_REENTER
We are currently using this flag to check whether it's safe
to call into ->request_fn(). If it is set, we punt to kblockd.
But we get a lot of false positives and excessive punts to
kblockd, which hurts performance.

The only real abuser of this infrastructure is SCSI. So export
the async queue run and convert SCSI over to use that. There's
room for improvement in that SCSI need not always use the async
call, but this fixes our performance issue and they can fix that
up in due time.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-19 13:32:46 +02:00
Robert Richter
855357a217 perf, x86: Fix AMD family 15h FPU event constraints
Depending on the unit mask settings some FPU events may be scheduled
only on cpu counter #3. This patch fixes this.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@googlemail.com>
Link: http://lkml.kernel.org/r/1302913676-14352-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-19 10:07:55 +02:00
Andre Przywara
83112e688f perf, x86: Fix pre-defined cache-misses event for AMD family 15h cpus
With AMD cpu family 15h a unit mask was introduced for the Data Cache
Miss event (0x041/L1-dcache-load-misses). We need to enable bit 0
(first data cache miss or streaming store to a 64 B cache line) of
this mask to proper count data cache misses.

Now we set this bit for all families and models. In case a PMU does
not implement a unit mask for event 0x041 the bit is ignored.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302913676-14352-2-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-19 10:07:54 +02:00
Jens Axboe
5f45c69589 cfq-iosched: read_lock() does not always imply rcu_read_lock()
For some configurations of CONFIG_PREEMPT that is not true. So
get rid of __call_for_each_cic() and always uses the explicitly
rcu_read_lock() protected call_for_each_cic() instead.

This fixes a potential bug related to IO scheduler removal or
online switching.

Thanks to Paul McKenney for clarifying this.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-19 09:10:35 +02:00
Linus Torvalds
f0e615c3cb Linux 2.6.39-rc4 2011-04-18 21:26:00 -07:00
Linus Torvalds
e024f69de9 Merge branch 'for-39-rc4' of git://codeaurora.org/quic/kernel/davidb/linux-msm
* 'for-39-rc4' of git://codeaurora.org/quic/kernel/davidb/linux-msm:
  msm: timer: fix missing return value
  msm: Remove extraneous ffa device check
2011-04-18 15:44:29 -07:00
Rafael J. Wysocki
2ca6f62f59 PM: Fix error code paths executed after failing syscore_suspend()
If syscore_suspend() fails in suspend_enter(), create_image() or
resume_target_kernel(), it is necessary to call sysdev_resume(),
because sysdev_suspend() has been called already and succeeded
and we are going to abort the transition.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-18 23:58:59 +02:00
Linus Torvalds
96fd2d57b8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: xen-kbdfront - fix mouse getting stuck after save/restore
  Input: estimate number of events per packet
  Input: evdev - indicate buffer overrun with SYN_DROPPED
  Input: document event types and codes and their intended use
  Input: add KEY_IMAGES specifically for AL Image Browser
  Input: twl4030_keypad - fix potential NULL dereference in twl4030_kp_probe()
  Input: h3600_ts - fix error handling at connect
  Input: twl4030_keypad - avoid potential NULL-pointer dereference
2011-04-18 13:29:03 -07:00
Linus Torvalds
8a83f33100 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: add blk_run_queue_async
  block: blk_delay_queue() should use kblockd workqueue
  md: fix up raid1/raid10 unplugging.
  md: incorporate new plugging into raid5.
  md: provide generic support for handling unplug callbacks.
  md - remove old plugging code.
  md/dm - remove remains of plug_fn callback.
  md: use new plugging interface for RAID IO.
  block: drop queue lock before calling __blk_run_queue() for kblockd punt
  Revert "block: add callback function for unplug notification"
  block: Enhance new plugging support to support general callbacks
2011-04-18 13:21:18 -07:00
Jens Axboe
bd900d4580 block: kill blk_flush_plug_list() export
With all drivers and file systems converted, we only have
in-core use of this function. So remove the export.

Reporteed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 22:06:57 +02:00
Linus Torvalds
5d5b1b9f79 Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/powermac: Build fix with SMP and CPU hotplug
  powerpc/perf_event: Skip updating kernel counters if register value shrinks
  powerpc: Don't write protect kernel text with CONFIG_DYNAMIC_FTRACE enabled
  powerpc: Fix oops if scan_dispatch_log is called too early
  powerpc/pseries: Use a kmem cache for DTL buffers
  powerpc/kexec: Fix regression causing compile failure on UP
  powerpc/85xx: disable Suspend support if SMP enabled
  powerpc/e500mc: Remove CPU_FTR_MAYBE_CAN_NAP/CPU_FTR_MAYBE_CAN_DOZE
  powerpc/book3e: Fix CPU feature handling on 64-bit e5500
  powerpc: Check device status before adding serial device
  powerpc/85xx: Don't add disabled PCIe devices
2011-04-18 12:24:24 -07:00
Linus Torvalds
adff377bb1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (24 commits)
  Btrfs: fix free space cache leak
  Btrfs: avoid taking the chunk_mutex in do_chunk_alloc
  Btrfs end_bio_extent_readpage should look for locked bits
  Btrfs: don't force chunk allocation in find_free_extent
  Btrfs: Check validity before setting an acl
  Btrfs: Fix incorrect inode nlink in btrfs_link()
  Btrfs: Check if btrfs_next_leaf() returns error in btrfs_real_readdir()
  Btrfs: Check if btrfs_next_leaf() returns error in btrfs_listxattr()
  Btrfs: make uncache_state unconditional
  btrfs: using cached extent_state in set/unlock combinations
  Btrfs: avoid taking the trans_mutex in btrfs_end_transaction
  Btrfs: fix subvolume mount by name problem when default mount subvolume is set
  fix user annotation in ioctl.c
  Btrfs: check for duplicate iov_base's when doing dio reads
  btrfs: properly handle overlapping areas in memmove_extent_buffer
  Btrfs: fix memory leaks in btrfs_new_inode()
  Btrfs: check for duplicate iov_base's when doing dio reads
  Btrfs: reuse the extent_map we found when calling btrfs_get_extent
  Btrfs: do not use async submit for small DIO io's
  Btrfs: don't split dio bios if we don't have to
  ...
2011-04-18 12:24:05 -07:00
Linus Torvalds
d8bdc59f21 proc: do proper range check on readdir offset
Rather than pass in some random truncated offset to the pid-related
functions, check that the offset is in range up-front.

This is just cleanup, the previous commit fixed the real problem.

Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-18 10:36:54 -07:00
Linus Torvalds
c78193e9c7 next_pidmap: fix overflow condition
next_pidmap() just quietly accepted whatever 'last' pid that was passed
in, which is not all that safe when one of the users is /proc.

Admittedly the proc code should do some sanity checking on the range
(and that will be the next commit), but that doesn't mean that the
helper functions should just do that pidmap pointer arithmetic without
checking the range of its arguments.

So clamp 'last' to PID_MAX_LIMIT.  The fact that we then do "last+1"
doesn't really matter, the for-loop does check against the end of the
pidmap array properly (it's only the actual pointer arithmetic overflow
case we need to worry about, and going one bit beyond isn't going to
overflow).

[ Use PID_MAX_LIMIT rather than pid_max as per Eric Biederman ]

Reported-by: Tavis Ormandy <taviso@cmpxchg8b.com>
Analyzed-by: Robert Święcki <robert@swiecki.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-18 10:35:30 -07:00
J. Bruce Fields
4ee63624fd nfsd4: fix struct file leak on delegation
Introduced by acfdf5c383.

Cc: stable@kernel.org
Reported-by: Gerhard Heift <ml-nfs-linux-20110412-ef47@gheift.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-04-18 13:30:56 -04:00
Igor Mammedov
c36b58e8a9 Input: xen-kbdfront - fix mouse getting stuck after save/restore
Mouse gets "stuck" after restore of PV guest but buttons are in working
condition.

If driver has been configured for ABS coordinates at start it will get
XENKBD_TYPE_POS events and then suddenly after restore it'll start getting
XENKBD_TYPE_MOTION events, that will be dropped later and they won't get
into user-space.

Regression was introduced by hunk 5 and 6 of
5ea5254aa0ad269cfbd2875c973ef25ab5b5e9db
("Input: xen-kbdfront - advertise either absolute or relative
coordinates").

Driver on restore should ask xen for request-abs-pointer again if it is
available. So restore parts that did it before 5ea5254.

Acked-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
[v1: Expanded the commit description]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-04-18 10:17:45 -07:00
Jeff Brown
80b4895aa4 Input: estimate number of events per packet
Calculate a default based on the number of ABS axes, REL axes,
and MT slots for the device during input device registration.

Signed-off-by: Jeff Brown <jeffbrown@android.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2011-04-18 10:15:43 -07:00
Joerg Roedel
665d3e2af8 x86, gart: Make sure GART does not map physmem above 1TB
The GART can only map physical memory below 1TB. Make sure
the gart driver in the kernel does not try to map memory
above 1TB.

Cc: <stable@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-5-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2011-04-18 09:26:49 -07:00
Joerg Roedel
c34151a742 x86, gart: Set DISTLBWALKPRB bit always
The DISTLBWALKPRB bit must be set for the GART because the
gatt table is mapped UC. But the current code does not set
the bit at boot when the BIOS setup the aperture correctly.
Fix that by setting this bit when enabling the GART instead
of the other places.

Cc: <stable@kernel.org>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-4-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2011-04-18 09:26:48 -07:00
Joerg Roedel
af289bfe15 x86, gart: Convert spaces to tabs in enable_gart_translation
Probably by copy&paste this function was indented by spaces.
Convert this to tabs.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-3-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2011-04-18 09:26:48 -07:00
Guennadi Liakhovetski
b3c27b51db ASoC: add a module alias to the FSI driver
This patch enables FSI driver autoloading on sh-mobile systems.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: Simon Horman <horms@verge.net.au
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2011-04-18 17:14:28 +01:00
Mark Brown
fac56c2df5 Merge commit 'v2.6.39-rc3' into for-2.6.39 2011-04-18 17:12:14 +01:00
Bob Peterson
44ad37d69b GFS2: filesystem hang caused by incorrect lock order
This patch fixes a deadlock in GFS2 where two processes are trying
to reclaim an unlinked dinode:
One holds the inode glock and calls gfs2_lookup_by_inum trying to look
up the inode, which it can't, due to I_FREEING.  The other has set
I_FREEING from vfs and is at the beginning of gfs2_delete_inode
waiting for the glock, which is held by the first.  The solution is to
add a new non_block parameter to the gfs2_iget function that causes it
to return -ENOENT if the inode is being freed.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2011-04-18 15:23:50 +01:00
Steven Whitehouse
001e8e8df4 GFS2: Don't try to deallocate unlinked inodes when mounted ro
This adds a couple of missing tests to avoid read-only nodes
from attempting to deallocate unlinked inodes.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Reported-by: Michel Andre de la Porte <madelaporte@ubi.com>
2011-04-18 15:23:12 +01:00
Benjamin Marzinski
0ee532062f GFS2: directly write blocks past i_size
GFS2 was relying on the writepage code to write out the zeroed data for
fallocate.  However, with FALLOC_FL_KEEP_SIZE set, this may be past i_size.
If it is, it will be ignored.  To work around this, gfs2 now calls
write_dirty_buffer directly on the buffer_heads when FALLOC_FL_KEEP_SIZE
is set, and it's writing past i_size.

This version is just a cleanup of my last version

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2011-04-18 15:22:52 +01:00
Bob Peterson
deab72d379 GFS2: write_end error path fails to unlock transaction lock
I did an audit of gfs2's transaction glock for bugzilla bug
658619 and ran across this:

In function gfs2_write_end, in the unlikely event that
gfs2_meta_inode_buffer returns an error, the code may forget
to unlock the transaction lock because the "failed" label
appears after the call to function gfs2_trans_end.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2011-04-18 15:22:35 +01:00
Chris Mason
f65647c29b Btrfs: fix free space cache leak
The free space caching code was recently reworked to
cache all the pages it needed instead of using find_get_page everywhere.

One loop was missed though, so it ended up leaking pages.  This fixes
it to use our page array instead of find_get_page.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-18 08:55:34 -04:00
Christoph Hellwig
24ecfbe27f block: add blk_run_queue_async
Instead of overloading __blk_run_queue to force an offload to kblockd
add a new blk_run_queue_async helper to do it explicitly.  I've kept
the blk_queue_stopped check for now, but I suspect it's not needed
as the check we do when the workqueue items runs should be enough.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 11:41:33 +02:00
Jens Axboe
4521cc4ed5 block: blk_delay_queue() should use kblockd workqueue
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-18 11:36:39 +02:00
Axel Lin
2dd93c4f47 RTC: rtc-omap: Fix a leak of the IRQ during init failure
In omap_rtc_probe error path, free_irq() was using NULL rather than the
driver data as the data pointer so free_irq() wouldn't have matched.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: "George G. Davis" <gdavis@mvista.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: rtc-linux@googlegroups.com
Link: http://lkml.kernel.org/r/%3C1303005778.2889.2.camel%40phoenix%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-18 10:39:38 +02:00
Richard Cochran
1791f88143 posix clocks: Replace mutex with reader/writer semaphore
A dynamic posix clock is protected from asynchronous removal by a mutex.
However, using a mutex has the unwanted effect that a long running clock
operation in one process will unnecessarily block other processes.

For example, one process might call read() to get an external time stamp
coming in at one pulse per second. A second process calling clock_gettime
would have to wait for almost a whole second.

This patch fixes the issue by using a reader/writer semaphore instead of
a mutex.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/%3C20110330132421.GA31771%40riccoc20.at.omicron.at%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-18 10:39:38 +02:00
NeilBrown
c3b328ac84 md: fix up raid1/raid10 unplugging.
We just need to make sure that an unplug event wakes up the md
thread, which is exactly what mddev_check_plugged does.

Also remove some plug-related code that is no longer needed.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:43 +10:00
NeilBrown
7c13edc875 md: incorporate new plugging into raid5.
In raid5 plugging is used for 2 things:
 1/ collecting writes that require a bitmap update
 2/ collecting writes in the hope that we can create full
    stripes - or at least more-full.

We now release these different sets of stripes when plug_cnt
is zero.

Also in make_request, we call mddev_check_plug to hopefully increase
plug_cnt, and wake up the thread at the end if plugging wasn't
achieved for some reason.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:43 +10:00
NeilBrown
97658cdd3a md: provide generic support for handling unplug callbacks.
When an md device adds a request to a queue, it can call
mddev_check_plugged.
If this succeeds then we know that the md thread will be woken up
shortly, and ->plug_cnt will be non-zero until then, so some
processing can be delayed.

If it fails, then no unplug callback is expected and the make_request
function needs to do whatever is required to make the request happen.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:42 +10:00
NeilBrown
482c083492 md - remove old plugging code.
md has some plugging infrastructure for RAID5 to use because the
normal plugging infrastructure required a 'request_queue', and when
called from dm, RAID5 doesn't have one of those available.

This relied on the ->unplug_fn callback which doesn't exist any more.

So remove all of that code, both in md and raid5.  Subsequent patches
with restore the plugging functionality.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:42 +10:00
NeilBrown
af1db72d8b md/dm - remove remains of plug_fn callback.
Now that unplugging is done differently, the unplug_fn callback is
never called, so it can be completely discarded.

Signed-off-by: NeilBrown <neilb@suse.de>
2011-04-18 18:25:41 +10:00