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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>
This commit is contained in:
Michel Lespinasse 2010-08-09 17:21:20 -07:00 committed by Linus Torvalds
parent 424acaaeb3
commit a8618a0e8a
1 changed files with 10 additions and 15 deletions
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25
lib/rwsem.c
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@ -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);
}
/*