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| author | Michel Lespinasse <walken@google.com> | 2010-08-10 02:21:20 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-10 05:45:11 +0200 |
| commit | a8618a0e8a06f75c6efec2a5477861d704d48b28 (patch) | |
| tree | 02679a316c5dea69e337ff65219d7c116f5a59aa /lib/rwsem.c | |
| parent | rwsem: wake queued readers when writer blocks on active read lock (diff) | |
| download | linux-a8618a0e8a06f75c6efec2a5477861d704d48b28.tar.xz linux-a8618a0e8a06f75c6efec2a5477861d704d48b28.zip | |
rwsem: smaller wrappers around rwsem_down_failed_common
More code can be pushed from rwsem_down_read_failed and
rwsem_down_write_failed into rwsem_down_failed_common.
Following change adding down_read_critical infrastructure support also
enjoys having flags available in a register rather than having to fish it
out in the struct rwsem_waiter...
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Mike Waychison <mikew@google.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Ying Han <yinghan@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/rwsem.c')
| -rw-r--r-- | lib/rwsem.c | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/lib/rwsem.c b/lib/rwsem.c index 318d435dcebb..f236d7cd5cf3 100644 --- a/lib/rwsem.c +++ b/lib/rwsem.c @@ -171,8 +171,9 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wake_type) */ static struct rw_semaphore __sched * rwsem_down_failed_common(struct rw_semaphore *sem, - struct rwsem_waiter *waiter, signed long adjustment) + unsigned int flags, signed long adjustment) { + struct rwsem_waiter waiter; struct task_struct *tsk = current; signed long count; @@ -180,12 +181,13 @@ rwsem_down_failed_common(struct rw_semaphore *sem, /* set up my own style of waitqueue */ spin_lock_irq(&sem->wait_lock); - waiter->task = tsk; + waiter.task = tsk; + waiter.flags = flags; get_task_struct(tsk); if (list_empty(&sem->wait_list)) adjustment += RWSEM_WAITING_BIAS; - list_add_tail(&waiter->list, &sem->wait_list); + list_add_tail(&waiter.list, &sem->wait_list); /* we're now waiting on the lock, but no longer actively locking */ count = rwsem_atomic_update(adjustment, sem); @@ -206,7 +208,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, /* wait to be given the lock */ for (;;) { - if (!waiter->task) + if (!waiter.task) break; schedule(); set_task_state(tsk, TASK_UNINTERRUPTIBLE); @@ -223,11 +225,8 @@ rwsem_down_failed_common(struct rw_semaphore *sem, asmregparm struct rw_semaphore __sched * rwsem_down_read_failed(struct rw_semaphore *sem) { - struct rwsem_waiter waiter; - - waiter.flags = RWSEM_WAITING_FOR_READ; - rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_READ_BIAS); - return sem; + return rwsem_down_failed_common(sem, RWSEM_WAITING_FOR_READ, + -RWSEM_ACTIVE_READ_BIAS); } /* @@ -236,12 +235,8 @@ rwsem_down_read_failed(struct rw_semaphore *sem) asmregparm struct rw_semaphore __sched * rwsem_down_write_failed(struct rw_semaphore *sem) { - struct rwsem_waiter waiter; - - waiter.flags = RWSEM_WAITING_FOR_WRITE; - rwsem_down_failed_common(sem, &waiter, -RWSEM_ACTIVE_WRITE_BIAS); - - return sem; + return rwsem_down_failed_common(sem, RWSEM_WAITING_FOR_WRITE, + -RWSEM_ACTIVE_WRITE_BIAS); } /* |