From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Tue, 8 Sep 2015 01:01:14 -0300 Subject: Linux-libre 4.2-gnu --- drivers/md/dm-bio-prison.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/md/dm-bio-prison.h') diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h index 74cf01144..54352f009 100644 --- a/drivers/md/dm-bio-prison.h +++ b/drivers/md/dm-bio-prison.h @@ -101,6 +101,19 @@ void dm_cell_visit_release(struct dm_bio_prison *prison, void (*visit_fn)(void *, struct dm_bio_prison_cell *), void *context, struct dm_bio_prison_cell *cell); +/* + * Rather than always releasing the prisoners in a cell, the client may + * want to promote one of them to be the new holder. There is a race here + * though between releasing an empty cell, and other threads adding new + * inmates. So this function makes the decision with its lock held. + * + * This function can have two outcomes: + * i) An inmate is promoted to be the holder of the cell (return value of 0). + * ii) The cell has no inmate for promotion and is released (return value of 1). + */ +int dm_cell_promote_or_release(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell); + /*----------------------------------------------------------------*/ /* -- cgit v1.2.3