This helpers allows to bounce steal the uncompleted bios from a request so that they can be reissued on another path.
Signed-off-by: Christoph Hellwig <[email protected]> Reviewed-by: Sagi Grimberg <[email protected]> --- block/blk-core.c | 20 ++++++++++++++++++++ include/linux/blkdev.h | 2 ++ 2 files changed, 22 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index f02eb346c910..6f3db2c14843 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2724,6 +2724,26 @@ struct request *blk_fetch_request(struct request_queue *q) } EXPORT_SYMBOL(blk_fetch_request); +/* + * Steal bios from a request. The request must not have been partially + * completed before. + */ +void blk_steal_bios(struct bio_list *list, struct request *rq) +{ + if (rq->bio) { + if (list->tail) + list->tail->bi_next = rq->bio; + else + list->head = rq->bio; + list->tail = rq->biotail; + } + + rq->bio = NULL; + rq->biotail = NULL; + rq->__data_len = 0; +} +EXPORT_SYMBOL_GPL(blk_steal_bios); + /** * blk_update_request - Special helper function for request stacking drivers * @req: the request being processed diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 86dfeea16d4c..0ca5525ee5ce 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1109,6 +1109,8 @@ extern struct request *blk_peek_request(struct request_queue *q); extern void blk_start_request(struct request *rq); extern struct request *blk_fetch_request(struct request_queue *q); +void blk_steal_bios(struct bio_list *list, struct request *rq); + /* * Request completion related functions. * -- 2.14.1
