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* wait: add wait_event_cmd()Shaohua Li2013-11-141-0/+25
| | | | | | | | | | | Add a new API wait_event_cmd(). It's a variant of wait_even() with two commands executed. One is executed before sleep, another after sleep. Modified to match use wait.h approach based on suggestion by Peter Zijlstra <peterz@infradead.org> - neilb Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de>
* sched/wait: Fix __wait_event_interruptible_lock_irq_timeout()Heiko Carstens2013-11-011-1/+1
| | | | | | | | | | | | | | | | | __wait_event_interruptible_lock_irq_timeout() needs the timeout parameter passed instead of "ret". This magically compiled since the only user has a local ret variable. Luckily we got a build warning: CC drivers/s390/scsi/zfcp_qdio.o drivers/s390/scsi/zfcp_qdio.c: In function 'zfcp_qdio_sbal_get': include/linux/wait.h:780:15: warning: 'ret' may be used uninitialized Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20131031114814.GB5551@osiris Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Fix build breakageThierry Reding2013-10-231-1/+1
| | | | | | | | | | The wait_event_interruptible_lock_irq() macro is missing a semi-colon which causes a build failure in the i915 DRM driver. Signed-off-by: Thierry Reding <treding@nvidia.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1382528455-29911-1-git-send-email-treding@nvidia.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Introduce prepare_to_wait_event()Oleg Nesterov2013-10-161-10/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the new helper, prepare_to_wait_event() which should only be used by ___wait_event(). prepare_to_wait_event() returns -ERESTARTSYS if signal_pending_state() is true, otherwise it does prepare_to_wait/exclusive. This allows to uninline the signal-pending checks in wait_event*() macros. Also, it can initialize wait->private/func. We do not care if they were already initialized, the values are the same. This also shaves a couple of insns from the inlined code. This obviously makes prepare_*() path a little bit slower, but we are likely going to sleep anyway, so I think it makes sense to shrink .text: text data bss dec hex filename =================================================== before: 5126092 2959248 10117120 18202460 115bf5c vmlinux after: 5124618 2955152 10117120 18196890 115a99a vmlinux on my build. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131007161824.GA29757@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Add ___wait_cond_timeout() to wait_event*_timeout() tooOleg Nesterov2013-10-161-3/+3
| | | | | | | | | | | | | | | | | Commit 4c663cfc ("wait: fix false timeouts when using wait_event_timeout()") introduced the additional condition checks after a timeout but only in the "slow" __wait*() paths. wait_event_timeout(wq, CONDITION, 0) still returns 0 if CONDITION is already true and we do not call __wait*(). Now that we have ___wait_cond_timeout() we can use it instead to ensure that __ret will be properly updated. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131007183106.GA10973@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Clean up wait.h details a bitIngo Molnar2013-10-041-64/+60Star
| | | | | | | | | | | | | | | | | | | Since we are changing wait.h profoundly, use the opportunity to: - add a sentence to explain what this file is about - remove whitespace noise - prettify weird looking line break fixup attempts - standardize type definition and initialization sequences - use consistent style details No code is changed. Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-O8dIie5swnctqpupakatvqyq@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Make the __wait_event*() interface more friendlyPeter Zijlstra2013-10-041-58/+55Star
| | | | | | | | | | | | | Change all __wait_event*() implementations to match the corresponding wait_event*() signature for convenience. In particular this does away with the weird 'ret' logic. Since there are __wait_event*() users this requires we update them too. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092529.042563462@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_hrtimeout()Peter Zijlstra2013-10-041-13/+2Star
| | | | | | | | | | | | While not a whole-sale replacement like the others we can still reduce the size of __wait_event_hrtimeout() considerably by noting that the actual core of __wait_event_hrtimeout() is identical to what ___wait_event() generates. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.972793648@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_killable()Peter Zijlstra2013-10-041-16/+1Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.898691966@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_interruptible_lock_irq_timeout()Peter Zijlstra2013-10-041-19/+6Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.759956109@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_interruptible_lock_irq()Peter Zijlstra2013-10-041-20/+6Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.686006009@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_lock_irq()Peter Zijlstra2013-10-041-14/+6Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.612813379@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_interruptible_exclusive()Peter Zijlstra2013-10-041-20/+2Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.541716442@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_interruptible_timeout()Peter Zijlstra2013-10-041-15/+3Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.469616907@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_interruptible()Peter Zijlstra2013-10-041-15/+2Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.396949919@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event_timeout()Peter Zijlstra2013-10-041-11/+3Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.325264677@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Collapse __wait_event()Peter Zijlstra2013-10-041-11/+2Star
| | | | | | | | | | Reduce macro complexity by using the new ___wait_event() helper. No change in behaviour, identical generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.254863348@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Introduce ___wait_event()Peter Zijlstra2013-10-041-0/+36
| | | | | | | | | | | | | | | There's far too much duplication in the __wait_event macros; in order to fix this introduce ___wait_event() a macro with the capability to replace most other macros. With the previous patches changing the various __wait_event*() implementations to be more uniform; we can now collapse the lot without also changing generated code. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.181897111@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Change the wait_exclusive control flowPeter Zijlstra2013-10-041-4/+5
| | | | | | | | | | | Purely a preparatory patch; it changes the control flow to match what will soon be generated by generic code so that that patch can be a unity transform. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.107994763@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Change timeout logicPeter Zijlstra2013-10-041-13/+11Star
| | | | | | | | | | | | | | | | | | Commit 4c663cf ("wait: fix false timeouts when using wait_event_timeout()") introduced an additional condition check after a timeout but there's a few issues; - it forgot one site - it put the check after the main loop; not at the actual timeout check. Cure both; by wrapping the condition (as suggested by Oleg), this avoids double evaluation of 'condition' which could be quite big. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092528.028892896@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/wait: Make the signal_pending() checks consistentPeter Zijlstra2013-10-041-19/+16Star
| | | | | | | | | | | | | | | | | | | | | | | | | | There's two patterns to check signals in the __wait_event*() macros: if (!signal_pending(current)) { schedule(); continue; } ret = -ERESTARTSYS; break; And the more natural: if (signal_pending(current)) { ret = -ERESTARTSYS; break; } schedule(); Change them all into the latter form. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131002092527.956416254@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* [SCSI] zfcp: fix lock imbalance by reworking request queue lockingMartin Peschke2013-08-221-0/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds wait_event_interruptible_lock_irq_timeout(), which is a straight-forward descendant of wait_event_interruptible_timeout() and wait_event_interruptible_lock_irq(). The zfcp driver used to call wait_event_interruptible_timeout() in combination with some intricate and error-prone locking. Using wait_event_interruptible_lock_irq_timeout() as a replacement nicely cleans up that locking. This rework removes a situation that resulted in a locking imbalance in zfcp_qdio_sbal_get(): BUG: workqueue leaked lock or atomic: events/1/0xffffff00/10 last function: zfcp_fc_wka_port_offline+0x0/0xa0 [zfcp] It was introduced by commit c2af7545aaff3495d9bf9a7608c52f0af86fb194 "[SCSI] zfcp: Do not wait for SBALs on stopped queue", which had a new code path related to ZFCP_STATUS_ADAPTER_QDIOUP that took an early exit without a required lock being held. The problem occured when a special, non-SCSI I/O request was being submitted in process context, when the adapter's queues had been torn down. In this case the bug surfaced when the Fibre Channel port connection for a well-known address was closed during a concurrent adapter shut-down procedure, which is a rare constellation. This patch also fixes these warnings from the sparse tool (make C=1): drivers/s390/scsi/zfcp_qdio.c:224:12: warning: context imbalance in 'zfcp_qdio_sbal_check' - wrong count at exit drivers/s390/scsi/zfcp_qdio.c:244:5: warning: context imbalance in 'zfcp_qdio_sbal_get' - unexpected unlock Last but not least, we get rid of that crappy lock-unlock-lock sequence at the beginning of the critical section. It is okay to call zfcp_erp_adapter_reopen() with req_q_lock held. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Cc: stable@vger.kernel.org #2.6.35+ Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* Merge tag 'fscache-20130702' of ↵Linus Torvalds2013-07-021-0/+24
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull FS-Cache updates from David Howells: "This contains a number of fixes for various FS-Cache issues plus some cleanups. The commits are, in order: 1) Provide a system wait_on_atomic_t() and wake_up_atomic_t() sharing the bit-wait table (enhancement for #8). 2) Don't put spin_lock() in a while-condition as spin_lock() may have a do {} while(0) wrapper (cleanup). 3) Symbolically name i_mutex lock classes rather than using numbers in CacheFiles (cleanup). 4) Don't sleep in page release if __GFP_FS is not set (deadlock vs ext4). 5) Uninline fscache_object_init() (cleanup for #7). 6) Wrap checks on object state (cleanup for #7). 7) Simplify the object state machine by separating work states from wait states. 8) Simplify cookie retention by objects (NULL pointer deref fix). 9) Remove unused list_to_page() macro (cleanup). 10) Make the remaining-pages counter in the retrieval op atomic (assertion failure fix). 11) Don't use spin_is_locked() in assertions (assertion failure fix)" * tag 'fscache-20130702' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: FS-Cache: Don't use spin_is_locked() in assertions FS-Cache: The retrieval remaining-pages counter needs to be atomic_t cachefiles: remove unused macro list_to_page() FS-Cache: Simplify cookie retention for fscache_objects, fixing oops FS-Cache: Fix object state machine to have separate work and wait states FS-Cache: Wrap checks on object state FS-Cache: Uninline fscache_object_init() FS-Cache: Don't sleep in page release if __GFP_FS is not set CacheFiles: name i_mutex lock class explicitly fs/fscache: remove spin_lock() from the condition in while() Add wait_on_atomic_t() and wake_up_atomic_t()
| * Add wait_on_atomic_t() and wake_up_atomic_t()David Howells2013-05-151-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add wait_on_atomic_t() and wake_up_atomic_t() to indicate became-zero events on atomic_t types. This uses the bit-wake waitqueue table. The key is set to a value outside of the number of bits in a long so that wait_on_bit() won't be woken up accidentally. What I'm using this for is: in a following patch I add a counter to struct fscache_cookie to count the number of outstanding operations that need access to netfs data. The way this works is: (1) When a cookie is allocated, the counter is initialised to 1. (2) When an operation wants to access netfs data, it calls atomic_inc_unless() to increment the counter before it does so. If it was 0, then the counter isn't incremented, the operation isn't permitted to access the netfs data (which might by this point no longer exist) and the operation aborts in some appropriate manner. (3) When an operation finishes with the netfs data, it decrements the counter and if it reaches 0, calls wake_up_atomic_t() on it - the assumption being that it was the last blocker. (4) When a cookie is released, the counter is decremented and the releaser uses wait_on_atomic_t() to wait for the counter to become 0 - which should indicate no one is using the netfs data any longer. The netfs data can then be destroyed. There are some alternatives that I have thought of and that have been suggested by Tejun Heo: (A) Using wait_on_bit() to wait on a bit in the counter. This doesn't work because if that bit happens to be 0 then the wait won't happen - even if the counter is non-zero. (B) Using wait_on_bit() to wait on a flag elsewhere which is cleared when the counter reaches 0. Such a flag would be redundant and would add complexity. (C) Adding a waitqueue to fscache_cookie - this would expand that struct by several words for an event that happens just once in each cookie's lifetime. Further, cookies are generally per-file so there are likely to be a lot of them. (D) Similar to (C), but add a pointer to a waitqueue in the cookie instead of a waitqueue. This would add single word per cookie and so would be less of an expansion - but still an expansion. (E) Adding a static waitqueue to the fscache module. Generally this would be fine, but under certain circumstances many cookies will all get added at the same time (eg. NFS umount, cache withdrawal) thereby presenting scaling issues. Note that the wait may be significant as disk I/O may be in progress. So, I think reusing the wait_on_bit() waitqueue set is reasonable. I don't make much use of the waitqueue I need on a per-cookie basis, but sometimes I have a huge flood of the cookies to deal with. I also don't want to add a whole new set of global waitqueue tables specifically for the dec-to-0 event if I can reuse the bit tables. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Milosz Tanski <milosz@adfin.com> Acked-by: Jeff Layton <jlayton@redhat.com>
* | wait: fix false timeouts when using wait_event_timeout()Imre Deak2013-05-251-5/+11
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many callers of the wait_event_timeout() and wait_event_interruptible_timeout() expect that the return value will be positive if the specified condition becomes true before the timeout elapses. However, at the moment this isn't guaranteed. If the wake-up handler is delayed enough, the time remaining until timeout will be calculated as 0 - and passed back as a return value - even if the condition became true before the timeout has passed. Fix this by returning at least 1 if the condition becomes true. This semantic is in line with what wait_for_condition_timeout() does; see commit bb10ed09 ("sched: fix wait_for_completion_timeout() spurious failure under heavy load"). Daniel said "We have 3 instances of this bug in drm/i915. One case even where we switch between the interruptible and not interruptible wait_event_timeout variants, foolishly presuming they have the same semantics. I very much like this." One such bug is reported at https://bugs.freedesktop.org/show_bug.cgi?id=64133 Signed-off-by: Imre Deak <imre.deak@intel.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Jens Axboe <axboe@kernel.dk> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Dave Jones <davej@redhat.com> Cc: Lukas Czerner <lczerner@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: add wait_event_hrtimeout()Kent Overstreet2013-05-081-0/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Analagous to wait_event_timeout() and friends, this adds wait_event_hrtimeout() and wait_event_interruptible_hrtimeout(). Note that unlike the versions that use regular timers, these don't return the amount of time remaining when they return - instead, they return 0 or -ETIME if they timed out. because I was uncomfortable with the semantics of doing it the other way (that I could get it right, anyways). If the timer expires, there's no real guarantee that expire_time - current_time would be <= 0 - due to timer slack certainly, and I'm not sure I want to know the implications of the different clock bases in hrtimers. If the timer does expire and the code calculates that the time remaining is nonnegative, that could be even worse if the calling code then reuses that timeout. Probably safer to just return 0 then, but I could imagine weird bugs or at least unintended behaviour arising from that too. I came to the conclusion that if other users end up actually needing the amount of time remaining, the sanest thing to do would be to create a version that uses absolute timeouts instead of relative. [akpm@linux-foundation.org: fix description of `timeout' arg] Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: add wait_event_lock_irq() interfaceLukas Czerner2012-11-301-0/+164
| | | | | | | | | | | | | | | | | | | | | | | | | | | New wait_event{_interruptible}_lock_irq{_cmd} macros added. This commit moves the private wait_event_lock_irq() macro from MD to regular wait includes, introduces new macro wait_event_lock_irq_cmd() instead of using the old method with omitting cmd parameter which is ugly and makes a use of new macros in the MD. It also introduces the _interruptible_ variant. The use of new interface is when one have a special lock to protect data structures used in the condition, or one also needs to invoke "cmd" before putting it to sleep. All new macros are expected to be called with the lock taken. The lock is released before sleep and is reacquired afterwards. We will leave the macro with the lock held. Note to DM: IMO this should also fix theoretical race on waitqueue while using simultaneously wait_event_lock_irq() and wait_event() because of lack of locking around current state setting and wait queue removal. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: David Howells <dhowells@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* UAPI: (Scripted) Disintegrate include/linuxDavid Howells2012-10-131-19/+1Star
| | | | | | | | | Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
* Remove all #inclusions of asm/system.hDavid Howells2012-03-281-1/+0Star
| | | | | | | | | Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *` Signed-off-by: David Howells <dhowells@redhat.com>
* sched/wait: Add __wake_up_all_locked() APIThomas Gleixner2012-03-011-2/+3
| | | | | | | | | | | | | | For code which protects the waitqueue itself with another lock it makes no sense to acquire the waitqueue lock for wakeup all. Provide __wake_up_all_locked(). This is an optimization on the vanilla kernel (to be used by the PCI code) and an important semantic distinction on -rt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-ux6m4b8jonb9inx8xafh77ds@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep/waitqueues: Add better annotationPeter Zijlstra2011-12-211-2/+2
| | | | | | | | | | | | | | -> #2 (&tty->write_wait){-.-...}: is a lot more informative than: -> #2 (key#19){-.....}: Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-8zpopbny51023rdb0qq67eye@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* wait: using uninitialized member of wait queueEvgeny Kuznetsov2010-10-051-0/+1
| | | | | | | | | | | | | | | | | | The "flags" member of "struct wait_queue_t" is used in several places in the kernel code without beeing initialized by init_wait(). "flags" is used in bitwise operations. If "flags" not initialized then unexpected behaviour may take place. Incorrect flags might used later in code. Added initialization of "wait_queue_t.flags" with zero value into "init_wait". Signed-off-by: Evgeny Kuznetsov <EXT-Eugeny.Kuznetsov@nokia.com> [ The bit we care about does end up being initialized by both prepare_to_wait() and add_to_wait_queue(), so this doesn't seem to cause actual bugs, but is definitely the right thing to do -Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6Linus Torvalds2010-05-211-0/+149
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (229 commits) USB: remove unused usb_buffer_alloc and usb_buffer_free macros usb: musb: update gfp/slab.h includes USB: ftdi_sio: fix legacy SIO-device header USB: kl5usb105: reimplement using generic framework USB: kl5usb105: minor clean ups USB: kl5usb105: fix memory leak USB: io_ti: use kfifo to implement write buffering USB: io_ti: remove unsused private counter USB: ti_usb: use kfifo to implement write buffering USB: ir-usb: fix incorrect write-buffer length USB: aircable: fix incorrect write-buffer length USB: safe_serial: straighten out read processing USB: safe_serial: reimplement read using generic framework USB: safe_serial: reimplement write using generic framework usb-storage: always print quirks USB: usb-storage: trivial debug improvements USB: oti6858: use port write fifo USB: oti6858: use kfifo to implement write buffering USB: cypress_m8: use kfifo to implement write buffering USB: cypress_m8: remove unused drain define ... Fix up conflicts (due to usb_buffer_alloc/free renaming) in drivers/input/tablet/acecad.c drivers/input/tablet/kbtab.c drivers/input/tablet/wacom_sys.c drivers/media/video/gspca/gspca.c sound/usb/usbaudio.c
| * wait_event_interruptible_locked() interfaceMichal Nazarewicz2010-05-201-0/+149
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New wait_event_interruptible{,_exclusive}_locked{,_irq} macros added. They work just like versions without _locked* suffix but require the wait queue's lock to be held. Also __wake_up_locked() is now exported as to pair it with the above macros. The use case of this new facility is when one uses wait queue's lock to protect a data structure. This may be advantageous if the structure needs to be protected by a spinlock anyway. In particular, with additional spinlock the following code has to be used to wait for a condition: spin_lock(&data.lock); ... for (ret = 0; !ret && !(condition); ) { spin_unlock(&data.lock); ret = wait_event_interruptible(data.wqh, (condition)); spin_lock(&data.lock); } ... spin_unlock(&data.lock); This looks bizarre plus wait_event_interruptible() locks the wait queue's lock anyway so there is a unlock+lock sequence where it could be avoided. To avoid those problems and benefit from wait queue's lock, a code similar to the following should be used: /* Waiting */ spin_lock(&data.wqh.lock); ... ret = wait_event_interruptible_locked(data.wqh, (condition)); ... spin_unlock(&data.wqh.lock); /* Waiting exclusively */ spin_lock(&data.whq.lock); ... ret = wait_event_interruptible_exclusive_locked(data.whq, (condition)); ... spin_unlock(&data.whq.lock); /* Waking up */ spin_lock(&data.wqh.lock); ... wake_up_locked(&data.wqh); ... spin_unlock(&data.wqh.lock); When spin_lock_irq() is used matching versions of macros need to be used (*_locked_irq()). Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Takashi Iwai <tiwai@suse.de> Cc: David Howells <dhowells@redhat.com> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | sched, wait: Use wrapper functionsChangli Gao2010-05-111-20/+15Star
|/ | | | | | | | | | | | | | | | | | | | | epoll should not touch flags in wait_queue_t. This patch introduces a new function __add_wait_queue_exclusive(), for the users, who use wait queue as a LIFO queue. __add_wait_queue_tail_exclusive() is introduced too instead of add_wait_queue_exclusive_locked(). remove_wait_queue_locked() is removed, as it is a duplicate of __remove_wait_queue(), disliked by users, and with less users. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: <containers@lists.linux-foundation.org> LKML-Reference: <1273214006-2979-1-git-send-email-xiaosuo@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Rename sync argumentsPeter Zijlstra2009-09-151-2/+2
| | | | | | | | | | In order to extend the functions to have more than 1 flag (sync), rename the argument to flags, and explicitly define a WF_ space for individual flags. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* locking, sched: Give waitqueue spinlocks their own lockdep classesPeter Zijlstra2009-08-101-1/+8
| | | | | | | | | | | | | | | | | | | Give waitqueue spinlocks their own lockdep classes when they are initialised from init_waitqueue_head(). This means that struct wait_queue::func functions can operate other waitqueues. This is used by CacheFiles to catch the page from a backing fs being unlocked and to wake up another thread to take a copy of it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Takashi Iwai <tiwai@suse.de> Cc: linux-cachefs@redhat.com Cc: torvalds@osdl.org Cc: akpm@linux-foundation.org LKML-Reference: <20090810113305.17284.81508.stgit@warthog.procyon.org.uk> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge commit 'v2.6.30-rc5' into sched/coreIngo Molnar2009-05-111-2/+4
|\ | | | | | | | | | | Merge reason: sched/core was on .30-rc1 before, update to latest fixes Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * net: Avoid extra wakeups of threads blocked in wait_for_packet()Eric Dumazet2009-04-281-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In 2.6.25 we added UDP mem accounting. This unfortunatly added a penalty when a frame is transmitted, since we have at TX completion time to call sock_wfree() to perform necessary memory accounting. This calls sock_def_write_space() and utimately scheduler if any thread is waiting on the socket. Thread(s) waiting for an incoming frame was scheduled, then had to sleep again as event was meaningless. (All threads waiting on a socket are using same sk_sleep anchor) This adds lot of extra wakeups and increases latencies, as noted by Christoph Lameter, and slows down softirq handler. Reference : http://marc.info/?l=linux-netdev&m=124060437012283&w=2 Fortunatly, Davide Libenzi recently added concept of keyed wakeups into kernel, and particularly for sockets (see commit 37e5540b3c9d838eb20f2ca8ea2eb8072271e403 epoll keyed wakeups: make sockets use keyed wakeups) Davide goal was to optimize epoll, but this new wakeup infrastructure can help non epoll users as well, if they care to setup an appropriate handler. This patch introduces new DEFINE_WAIT_FUNC() helper and uses it in wait_for_packet(), so that only relevant event can wakeup a thread blocked in this function. Trace of function calls from bnx2 TX completion bnx2_poll_work() is : __kfree_skb() skb_release_head_state() sock_wfree() sock_def_write_space() __wake_up_sync_key() __wake_up_common() receiver_wake_function() : Stops here since thread is waiting for an INPUT Reported-by: Christoph Lameter <cl@linux.com> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | wait: don't use __wake_up_common()Johannes Weiner2009-04-141-2/+0Star
|/ | | | | | | | | | | | | | | | | | | | | '777c6c5 wait: prevent exclusive waiter starvation' made __wake_up_common() global to be used from abort_exclusive_wait(). It was needed to do a wake-up with the waitqueue lock held while passing down a key to the wake-up function. Since '4ede816 epoll keyed wakeups: add __wake_up_locked_key() and __wake_up_sync_key()' there is an appropriate wrapper for this case: __wake_up_locked_key(). Use it here and make __wake_up_common() private to the scheduler again. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1239720785-19661-1-git-send-email-hannes@cmpxchg.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* epoll keyed wakeups: introduce new *_poll() wakeup macrosDavide Libenzi2009-04-011-13/+9Star
| | | | | | | | | | | | | | | Introduce new wakeup macros that allow passing an event mask to the wakeup targets. They exactly mimic their non-_poll() counterpart, with the added event mask passing capability. I did add only the ones currently requested, avoiding the _nr() and _all() for the moment. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: William Lee Irwin III <wli@movementarian.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll keyed wakeups: add __wake_up_locked_key() and __wake_up_sync_key()Davide Libenzi2009-04-011-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset introduces wakeup hints for some of the most popular (from epoll POV) devices, so that epoll code can avoid spurious wakeups on its waiters. The problem with epoll is that the callback-based wakeups do not, ATM, carry any information about the events the wakeup is related to. So the only choice epoll has (not being able to call f_op->poll() from inside the callback), is to add the file* to a ready-list and resolve the real events later on, at epoll_wait() (or its own f_op->poll()) time. This can cause spurious wakeups, since the wake_up() itself might be for an event the caller is not interested into. The rate of these spurious wakeup can be pretty high in case of many network sockets being monitored. By allowing devices to report the events the wakeups refer to (at least the two major classes - POLLIN/POLLOUT), we are able to spare useless wakeups by proper handling inside the epoll's poll callback. Epoll will have in any case to call f_op->poll() on the file* later on, since the change to be done in order to have the full event set sent via wakeup, is too invasive for the way our f_op->poll() system works (the full event set is calculated inside the poll function - there are too many of them to even start thinking the change - also poll/select would need change too). Epoll is changed in a way that both devices which send event hints, and the ones that don't, are correctly handled. The former will gain some efficiency though. As a general rule for devices, would be to add an event mask by using key-aware wakeup macros, when making up poll wait queues. I tested it (together with the epoll's poll fix patch Andrew has in -mm) and wakeups for the supported devices are correctly filtered. Test program available here: http://www.xmailserver.org/epoll_test.c This patch: Nothing revolutionary here. Just using the available "key" that our wakeup core already support. The __wake_up_locked_key() was no brainer, since both __wake_up_locked() and __wake_up_locked_key() are thin wrappers around __wake_up_common(). The __wake_up_sync() function had a body, so the choice was between borrowing the body for __wake_up_sync_key() and calling it from __wake_up_sync(), or make an inline and calling it from both. I chose the former since in most archs it all resolves to "mov $0, REG; jmp ADDR". Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: William Lee Irwin III <wli@movementarian.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: prevent exclusive waiter starvationJohannes Weiner2009-02-051-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With exclusive waiters, every process woken up through the wait queue must ensure that the next waiter down the line is woken when it has finished. Interruptible waiters don't do that when aborting due to a signal. And if an aborting waiter is concurrently woken up through the waitqueue, noone will ever wake up the next waiter. This has been observed with __wait_on_bit_lock() used by lock_page_killable(): the first contender on the queue was aborting when the actual lock holder woke it up concurrently. The aborted contender didn't acquire the lock and therefor never did an unlock followed by waking up the next waiter. Add abort_exclusive_wait() which removes the process' wait descriptor from the waitqueue, iff still queued, or wakes up the next waiter otherwise. It does so under the waitqueue lock. Racing with a wake up means the aborting process is either already woken (removed from the queue) and will wake up the next waiter, or it will remove itself from the queue and the concurrent wake up will apply to the next waiter after it. Use abort_exclusive_wait() in __wait_event_interruptible_exclusive() and __wait_on_bit_lock() when they were interrupted by other means than a wake up through the queue. [akpm@linux-foundation.org: coding-style fixes] Reported-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Mentored-by: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chuck Lever <cel@citi.umich.edu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> ["after some testing"] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wait: kill is_sync_wait()Tejun Heo2008-10-161-9/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | is_sync_wait() is used to distinguish between sync and async waits. Basically sync waits are the ones initialized with init_waitqueue_entry() and async ones with init_waitqueue_func_entry(). The sync/async distinction is used only in prepare_to_wait[_exclusive]() and its only function is to skip setting the current task state if the wait is async. This has a few problems. * No one uses it. None of func_entry users use prepare_to_wait() functions, so the code path never gets executed. * The distinction is bogus. Maybe back when func_entry is used only by aio but it's now also used by epoll and in future possibly by 9p and poll/select. * Taking @state as argument and ignoring it silenly depending on how @wait is initialized is just a bad error-prone API. * It prevents func_entry waits from using wait->private for no good reason. This patch kills is_sync_wait() and the associated code paths from prepare_to_wait[_exclusive](). As there was no user of these code paths, this patch doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux: Remove all users of FASTCALL() macroHarvey Harrison2008-02-141-18/+16Star
| | | | | | | | | FASTCALL() is always expanded to empty, remove it. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockdep: annotate epollPeter Zijlstra2008-02-051-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Sat, 2008-01-05 at 13:35 -0800, Davide Libenzi wrote: > I remember I talked with Arjan about this time ago. Basically, since 1) > you can drop an epoll fd inside another epoll fd 2) callback-based wakeups > are used, you can see a wake_up() from inside another wake_up(), but they > will never refer to the same lock instance. > Think about: > > dfd = socket(...); > efd1 = epoll_create(); > efd2 = epoll_create(); > epoll_ctl(efd1, EPOLL_CTL_ADD, dfd, ...); > epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...); > > When a packet arrives to the device underneath "dfd", the net code will > issue a wake_up() on its poll wake list. Epoll (efd1) has installed a > callback wakeup entry on that queue, and the wake_up() performed by the > "dfd" net code will end up in ep_poll_callback(). At this point epoll > (efd1) notices that it may have some event ready, so it needs to wake up > the waiters on its poll wait list (efd2). So it calls ep_poll_safewake() > that ends up in another wake_up(), after having checked about the > recursion constraints. That are, no more than EP_MAX_POLLWAKE_NESTS, to > avoid stack blasting. Never hit the same queue, to avoid loops like: > > epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...); > epoll_ctl(efd3, EPOLL_CTL_ADD, efd2, ...); > epoll_ctl(efd4, EPOLL_CTL_ADD, efd3, ...); > epoll_ctl(efd1, EPOLL_CTL_ADD, efd4, ...); > > The code "if (tncur->wq == wq || ..." prevents re-entering the same > queue/lock. Since the epoll code is very careful to not nest same instance locks allow the recursion. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add wait_event_killableMatthew Wilcox2007-12-061-0/+41
| | | | Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
* wait: Use TASK_NORMALMatthew Wilcox2007-12-061-5/+6
| | | | | | Also move wake_up_locked() to be with the related functions Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
* sched: clean up sleep_on() APIsIngo Molnar2007-07-091-8/+8
| | | | | | | | | clean up the sleep_on() APIs: - do not use fastcall - replace fragile macro magic with proper inline functions Signed-off-by: Ingo Molnar <mingo@elte.hu>
* [PATCH] lockdep: annotate DECLARE_WAIT_QUEUE_HEADPeter Zijlstra2006-10-301-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel: INFO: trying to register non-static key. kernel: the code is fine but needs lockdep annotation. kernel: turning off the locking correctness validator. kernel: [<c04051ed>] show_trace_log_lvl+0x58/0x16a kernel: [<c04057fa>] show_trace+0xd/0x10 kernel: [<c0405913>] dump_stack+0x19/0x1b kernel: [<c043b1e2>] __lock_acquire+0xf0/0x90d kernel: [<c043bf70>] lock_acquire+0x4b/0x6b kernel: [<c061472f>] _spin_lock_irqsave+0x22/0x32 kernel: [<c04363d3>] prepare_to_wait+0x17/0x4b kernel: [<f89a24b6>] lpfc_do_work+0xdd/0xcc2 [lpfc] kernel: [<c04361b9>] kthread+0xc3/0xf2 kernel: [<c0402005>] kernel_thread_helper+0x5/0xb Another case of non-static lockdep keys; duplicate the paradigm set by DECLARE_COMPLETION_ONSTACK and introduce DECLARE_WAIT_QUEUE_HEAD_ONSTACK. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Greg KH <gregkh@suse.de> Cc: Markus Lidel <markus.lidel@shadowconnect.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Arjan van de Ven <arjan@infradead.org> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>