Skip to content
Commit 61e02392 authored by Will Deacon's avatar Will Deacon Committed by Ingo Molnar
Browse files

locking/atomic/bitops: Document and clarify ordering semantics for failed test_and_{}_bit()



A test_and_{}_bit() operation fails if the value of the bit is such that
the modification does not take place. For example, if test_and_set_bit()
returns 1. In these cases, follow the behaviour of cmpxchg and allow the
operation to be unordered. This also applies to test_and_set_bit_lock()
if the lock is found to be be taken already.

Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1518528619-20049-1-git-send-email-will.deacon@arm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 11dc1322
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment