block: introduce rq_list_move

When iterating a list, a particular request may need to be moved for
special handling. Provide a helper function to achieve that so drivers
don't need to reimplement rqlist manipulation.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220105170518.3181469-4-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Keith Busch 2022-01-05 09:05:17 -08:00 committed by Jens Axboe
parent 3764fd05e1
commit d2528be7a8

View file

@ -249,6 +249,23 @@ static inline unsigned short req_get_ioprio(struct request *req)
#define rq_list_next(rq) (rq)->rq_next
#define rq_list_empty(list) ((list) == (struct request *) NULL)
/**
* rq_list_move() - move a struct request from one list to another
* @src: The source list @rq is currently in
* @dst: The destination list that @rq will be appended to
* @rq: The request to move
* @prev: The request preceding @rq in @src (NULL if @rq is the head)
*/
static void inline rq_list_move(struct request **src, struct request **dst,
struct request *rq, struct request *prev)
{
if (prev)
prev->rq_next = rq->rq_next;
else
*src = rq->rq_next;
rq_list_add(dst, rq);
}
enum blk_eh_timer_return {
BLK_EH_DONE, /* drivers has completed the command */
BLK_EH_RESET_TIMER, /* reset timer and try again */