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-rw-r--r--block/blk-core.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 62cf92550512..279e3c432d7b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -143,6 +143,7 @@ static const struct {
[BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
[BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
[BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
+ [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
/* device mapper special case, should not leak out: */
[BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
@@ -1314,6 +1315,11 @@ retry:
if (!IS_ERR(rq))
return rq;
+ if (op & REQ_NOWAIT) {
+ blk_put_rl(rl);
+ return ERR_PTR(-EAGAIN);
+ }
+
if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) {
blk_put_rl(rl);
return rq;
@@ -1961,6 +1967,14 @@ generic_make_request_checks(struct bio *bio)
goto end_io;
}
+ /*
+ * For a REQ_NOWAIT based request, return -EOPNOTSUPP
+ * if queue is not a request based queue.
+ */
+
+ if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q))
+ goto not_supported;
+
part = bio->bi_bdev->bd_part;
if (should_fail_request(part, bio->bi_iter.bi_size) ||
should_fail_request(&part_to_disk(part)->part0,
@@ -2118,7 +2132,7 @@ blk_qc_t generic_make_request(struct bio *bio)
do {
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
- if (likely(blk_queue_enter(q, false) == 0)) {
+ if (likely(blk_queue_enter(q, bio->bi_opf & REQ_NOWAIT) == 0)) {
struct bio_list lower, same;
/* Create a fresh bio_list for all subordinate requests */
@@ -2143,7 +2157,11 @@ blk_qc_t generic_make_request(struct bio *bio)
bio_list_merge(&bio_list_on_stack[0], &same);
bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
} else {
- bio_io_error(bio);
+ if (unlikely(!blk_queue_dying(q) &&
+ (bio->bi_opf & REQ_NOWAIT)))
+ bio_wouldblock_error(bio);
+ else
+ bio_io_error(bio);
}
bio = bio_list_pop(&bio_list_on_stack[0]);
} while (bio);
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