Provide a way for the caller to specify that IO should be marked with REQ_NOWAIT to avoid blocking on allocation.
Signed-off-by: Jens Axboe <[email protected]> --- block/blk-core.c | 6 ++++++ include/linux/blkdev.h | 1 + 2 files changed, 7 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index 03252af8c82c..62a4904db921 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -958,6 +958,7 @@ generic_make_request_checks(struct bio *bio) struct request_queue *q; int nr_sectors = bio_sectors(bio); blk_status_t status = BLK_STS_IOERR; + struct blk_plug *plug; char b[BDEVNAME_SIZE]; might_sleep(); @@ -971,6 +972,10 @@ generic_make_request_checks(struct bio *bio) goto end_io; } + plug = blk_mq_plug(q, bio); + if (plug && plug->nowait) + bio->bi_opf |= REQ_NOWAIT; + /* * For a REQ_NOWAIT based request, return -EOPNOTSUPP * if queue is not a request based queue. @@ -1800,6 +1805,7 @@ void blk_start_plug(struct blk_plug *plug) INIT_LIST_HEAD(&plug->cb_list); plug->rq_count = 0; plug->multiple_queues = false; + plug->nowait = false; /* * Store ordering should not be needed here, since a potential diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 8fd900998b4e..6e067dca94cf 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1189,6 +1189,7 @@ struct blk_plug { struct list_head cb_list; /* md requires an unplug callback */ unsigned short rq_count; bool multiple_queues; + bool nowait; }; #define BLK_MAX_REQUEST_COUNT 16 #define BLK_PLUG_FLUSH_SIZE (128 * 1024) -- 2.27.0
