If bio sets 'bi_failover_rq' callback it'll get transfered to the appropriate request's 'failover_rq' using blk_init_request_from_bio().
This callback is expected to use the blk_steal_bios() interface to transfer a request's bios back to a bio-based request_queue. This will be used by both NVMe multipath and DM multipath. Without it DM multipath cannot get access to NVMe-specific error handling that NVMe core provides in nvme_complete_rq(). Signed-off-by: Mike Snitzer <[email protected]> --- block/blk-core.c | 2 ++ block/blk-mq.c | 1 + include/linux/blk_types.h | 4 ++++ include/linux/blkdev.h | 6 ++++++ 4 files changed, 13 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index b8881750a3ac..95bdc4f2b11d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1872,6 +1872,8 @@ void blk_init_request_from_bio(struct request *req, struct bio *bio) else req->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); req->write_hint = bio->bi_write_hint; + if (bio->bi_failover_rq) + req->failover_rq = bio->bi_failover_rq; blk_rq_bio_prep(req->q, req, bio); } EXPORT_SYMBOL_GPL(blk_init_request_from_bio); diff --git a/block/blk-mq.c b/block/blk-mq.c index 11097477eeab..bb52f8283f07 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -320,6 +320,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, rq->end_io = NULL; rq->end_io_data = NULL; + rq->failover_rq = NULL; rq->next_rq = NULL; data->ctx->rq_dispatched[op_is_sync(op)]++; diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index a1e628e032da..c3a952991814 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -18,6 +18,9 @@ struct io_context; struct cgroup_subsys_state; typedef void (bio_end_io_t) (struct bio *); +struct request; +typedef void (rq_failover_fn)(struct request *); + /* * Block error status values. See block/blk-core:blk_errors for the details. */ @@ -77,6 +80,7 @@ struct bio { atomic_t __bi_remaining; bio_end_io_t *bi_end_io; + rq_failover_fn *bi_failover_rq; void *bi_private; #ifdef CONFIG_BLK_CGROUP diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 8089ca17db9a..46bcd782debe 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -237,6 +237,12 @@ struct request { rq_end_io_fn *end_io; void *end_io_data; + /* + * callback to failover request's bios back to upper layer + * bio-based queue using blk_steal_bios(). + */ + rq_failover_fn *failover_rq; + /* for bidi */ struct request *next_rq; }; -- 2.15.0 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
