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| author |   Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:27:03 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:34 +0200 |
| commit | f9852b74bec0117b888da39d070c323ea1cb7f4c (patch) | |
| tree | 7a0414aeaa3fd15a67754f8f87ce511fff8dc0d6 /kernel/locking | |
| parent | locking/atomic, arch/mips: Convert to _relaxed atomics (diff) | |
| download | linux-dev-f9852b74bec0117b888da39d070c323ea1cb7f4c.tar.xz linux-dev-f9852b74bec0117b888da39d070c323ea1cb7f4c.zip | |
locking/atomic, arch/qrwlock: Employ atomic_fetch_add_acquire()
The only reason for the current code is to make GCC emit only the
"LOCK XADD" instruction on x86 (and not do a pointless extra ADD on
the result), do so nicer.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <waiman.long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/qrwlock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c index fec082338668..19248ddf37ce 100644 --- a/kernel/locking/qrwlock.c +++ b/kernel/locking/qrwlock.c @@ -93,7 +93,7 @@ void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts) * that accesses can't leak upwards out of our subsequent critical * section in the case that the lock is currently held for write. */ - cnts = atomic_add_return_acquire(_QR_BIAS, &lock->cnts) - _QR_BIAS; + cnts = atomic_fetch_add_acquire(_QR_BIAS, &lock->cnts); rspin_until_writer_unlock(lock, cnts); /* |