[PATCH] 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.

Signed-off-by: Dan Williams
---

This at least was the guarantee we had with sh->lock...

drivers/md/raid5.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index dbae459..bd95123 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3116,7 +3116,7 @@ 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);
@@ -3377,7 +3377,7 @@ finish:

return_io(s.return_bi);

- clear_bit(STRIPE_ACTIVE, &sh->state);
+ clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
}

static void raid5_activate_delayed(raid5_conf_t *conf)

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