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>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index f5df8f687b4d..5f68d0a391ce 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -108,7 +108,7 @@ static inline unsigned __read_seqcount_begin(const seqcount_t *s)
         unsigned ret;
 
 repeat:
-        ret = ACCESS_ONCE(s->sequence);
+        ret = READ_ONCE(s->sequence);
         if (unlikely(ret & 1)) {
                 cpu_relax();
                 goto repeat;
@@ -127,7 +127,7 @@ repeat:
  */
 static inline unsigned raw_read_seqcount(const seqcount_t *s)
 {
-        unsigned ret = ACCESS_ONCE(s->sequence);
+        unsigned ret = READ_ONCE(s->sequence);
         smp_rmb();
         return ret;
 }
@@ -179,7 +179,7 @@ static inline unsigned read_seqcount_begin(const seqcount_t *s)
  */
 static inline unsigned raw_seqcount_begin(const seqcount_t *s)
 {
-        unsigned ret = ACCESS_ONCE(s->sequence);
+        unsigned ret = READ_ONCE(s->sequence);
         smp_rmb();
         return ret & ~1;
 }