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authorMichel Lespinasse <walken@google.com>2010-08-09 17:21:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-09 20:45:11 -0700
commita8618a0e8a06f75c6efec2a5477861d704d48b28 (patch)
tree02679a316c5dea69e337ff65219d7c116f5a59aa /lib
parent424acaaeb3a3932d64a9b4bd59df6cf72c22d8f3 (diff)
downloadblackbird-op-linux-a8618a0e8a06f75c6efec2a5477861d704d48b28.tar.gz
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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')
-rw-r--r--lib/rwsem.c25
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);
}
/*
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