From ef71de8b15d891b27b8c983a9a8972b11cb4576a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 2 Nov 2017 21:29:51 +0300 Subject: [PATCH] block: add a blk_steal_bios helper 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 Reviewed-by: Sagi Grimberg Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- block/blk-core.c | 21 +++++++++++++++++++++ include/linux/blkdev.h | 2 ++ 2 files changed, 23 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index 96aaa3a419a3..68cfe6780a9b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2769,6 +2769,27 @@ struct request *blk_fetch_request(struct request_queue *q) } EXPORT_SYMBOL(blk_fetch_request); +/* + * Steal bios from a request and add them to a bio list. + * 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 eda3d25c0f68..fddda6a1f9b5 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1094,6 +1094,8 @@ 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. *