summaryrefslogtreecommitdiffstats
path: root/kernel/locking/rwsem-xadd.c
diff options
context:
space:
mode:
authorDavidlohr Bueso <dave@stgolabs.net>2015-02-22 19:31:41 -0800
committerIngo Molnar <mingo@kernel.org>2015-02-24 08:44:16 +0100
commit4d3199e4ca8e6670b54dc5ee070ffd54385988e9 (patch)
tree5529bcb16c3217c02416e0d17d7c28f277c63581 /kernel/locking/rwsem-xadd.c
parent2ae79026818e7d49fead82b79b1a543e3b9c8a23 (diff)
downloadlinux-4d3199e4ca8e6670b54dc5ee070ffd54385988e9.tar.bz2
locking: Remove ACCESS_ONCE() usage
With the new standardized functions, we can replace all ACCESS_ONCE() calls across relevant locking - this includes lockref and seqlock while at it. ACCESS_ONCE() does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Update the new calls regardless of if it is a scalar type, this is cleaner than having three alternatives. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1424662301.6539.18.camel@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/rwsem-xadd.c')
-rw-r--r--kernel/locking/rwsem-xadd.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index e4ad019e23f5..06e2214edf98 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -279,7 +279,7 @@ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
*/
static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
{
- long old, count = ACCESS_ONCE(sem->count);
+ long old, count = READ_ONCE(sem->count);
while (true) {
if (!(count == 0 || count == RWSEM_WAITING_BIAS))
@@ -304,9 +304,9 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
return false;
rcu_read_lock();
- owner = ACCESS_ONCE(sem->owner);
+ owner = READ_ONCE(sem->owner);
if (!owner) {
- long count = ACCESS_ONCE(sem->count);
+ long count = READ_ONCE(sem->count);
/*
* If sem->owner is not set, yet we have just recently entered the
* slowpath with the lock being active, then there is a possibility
@@ -385,7 +385,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
goto done;
while (true) {
- owner = ACCESS_ONCE(sem->owner);
+ owner = READ_ONCE(sem->owner);
if (owner && !rwsem_spin_on_owner(sem, owner))
break;
@@ -459,7 +459,7 @@ struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
/* we're now waiting on the lock, but no longer actively locking */
if (waiting) {
- count = ACCESS_ONCE(sem->count);
+ count = READ_ONCE(sem->count);
/*
* If there were already threads queued before us and there are