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| author | Davidlohr Bueso <dave@stgolabs.net> | 2015-02-23 04:31:41 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-02-24 08:44:16 +0100 |
| commit | 4d3199e4ca8e6670b54dc5ee070ffd54385988e9 (patch) | |
| tree | 5529bcb16c3217c02416e0d17d7c28f277c63581 /lib/lockref.c | |
| parent | Merge tag 'v4.0-rc1' into locking/core, to refresh the tree before merging ne... (diff) | |
| download | linux-4d3199e4ca8e6670b54dc5ee070ffd54385988e9.tar.xz linux-4d3199e4ca8e6670b54dc5ee070ffd54385988e9.zip | |
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 'lib/lockref.c')
| -rw-r--r-- | lib/lockref.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/lockref.c b/lib/lockref.c index ecb9a665ec19..494994bf17c8 100644 --- a/lib/lockref.c +++ b/lib/lockref.c @@ -18,7 +18,7 @@ #define CMPXCHG_LOOP(CODE, SUCCESS) do { \ struct lockref old; \ BUILD_BUG_ON(sizeof(old) != 8); \ - old.lock_count = ACCESS_ONCE(lockref->lock_count); \ + old.lock_count = READ_ONCE(lockref->lock_count); \ while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) { \ struct lockref new = old, prev = old; \ CODE \ |