md/raid5: STRIPE_ACTIVE has lock semantics, add barriers

All updates that occur under STRIPE_ACTIVE should be globally visible
when STRIPE_ACTIVE clears.  test_and_set_bit() implies a barrier, but
clear_bit() does not.

This is suitable for 3.1-stable.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
This commit is contained in:
Dan Williams 2011-11-08 16:22:06 +11:00 committed by NeilBrown
parent 9a3f530f39
commit 257a4b42af

View File

@ -3110,7 +3110,7 @@ static void handle_stripe(struct stripe_head *sh)
struct r5dev *pdev, *qdev;
clear_bit(STRIPE_HANDLE, &sh->state);
if (test_and_set_bit(STRIPE_ACTIVE, &sh->state)) {
if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
/* already being handled, ensure it gets handled
* again when current action finishes */
set_bit(STRIPE_HANDLE, &sh->state);
@ -3375,7 +3375,7 @@ finish:
return_io(s.return_bi);
clear_bit(STRIPE_ACTIVE, &sh->state);
clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
}
static void raid5_activate_delayed(struct r5conf *conf)