On Thu, 13 Sep 2007, Jens Axboe wrote:
> +
> +     /*
> +      * Ensure ordering with tag section
> +      */
> +     smp_mb__before_clear_bit();
> +
> +     if (unlikely(!test_and_clear_bit(tag, bqt->tag_map))) {

You don't need the "smp_mb__before_clear_bit()" there.

The regular "clear_bit()" needs it, but the "test_and_xxx()" versions are 
architecturally defined to be memory barriers, exactly because they are 
regularly used for locking.

This is even documented - see Documentation/atomic_ops.txt.

                Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to