On Tue, 24 Jul 2007, Trond Myklebust wrote:
>
> That's not what the Documentation/memory-barriers.txt states:
Hmm.. You're right. We only actually need it for the unconditional bitops,
like the *unlock* side.
IOW, if you do a spinlock with the bitops, the locking side should be able
to use a "test_and_set_bit()" on its own, but the unlocking side should be
smp_mb__before_clear_bit();
clear_bit();
because the ones that don't return a value also don't imply a memory
barrier.
Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
