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 <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
Cc: [email protected]
This commit is contained in:
Dan Williams 2011-11-08 16:22:06 +11:00 • committed by NeilBrown
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)