From: Goldwyn Rodrigues <rgold...@suse.com>
A new flag BIO_NONBLOCKING is introduced to identify bio's
orignating from iocb with IOCB_NONBLOCKING. struct request
are requested using BLK_MQ_REQ_NOWAIT if BIO_NONBLOCKING is set.
Signed-off-by: Goldwyn Rodrigues <rgold...@suse.com>
---
block/blk-core.c | 13 +++++++++++--
block/blk-mq.c | 18 ++++++++++++++++--
fs/direct-io.c | 11 +++++++++--
include/linux/blk_types.h | 1 +
4 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 14d7c07..9767573 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1257,6 +1257,11 @@ static struct request *get_request(struct request_queue
*q, int op,
if (!IS_ERR(rq))
return rq;
+ if (bio_flagged(bio, BIO_NONBLOCKING)) {
+ 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;
@@ -2035,7 +2040,7 @@ 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_flagged(bio,
BIO_NONBLOCKING)) == 0)) {
ret = q->make_request_fn(q, bio);
blk_queue_exit(q);
@@ -2044,7 +2049,11 @@ blk_qc_t generic_make_request(struct bio *bio)
} else {
struct bio *bio_next = bio_list_pop(current->bio_list);
- bio_io_error(bio);
+ if (unlikely(bio_flagged(bio, BIO_NONBLOCKING))) {
+ bio->bi_error = -EAGAIN;
+ bio_endio(bio);
+ } else
+ bio_io_error(bio);
bio = bio_next;
}
} while (bio);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 81caceb..7a7c674 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1213,6 +1213,8 @@ static struct request *blk_mq_map_request(struct
request_queue *q,
trace_block_getrq(q, bio, op);
blk_mq_set_alloc_data(&alloc_data, q, 0, ctx, hctx);
+ if (bio_flagged(bio, BIO_NONBLOCKING))
+ alloc_data.flags |= BLK_MQ_REQ_NOWAIT;
rq = __blk_mq_alloc_request(&alloc_data, op, op_flags);
data->hctx = alloc_data.hctx;
@@ -1286,8 +1288,14 @@ static blk_qc_t blk_mq_make_request(struct request_queue
*q, struct bio *bio)
return BLK_QC_T_NONE;
rq = blk_mq_map_request(q, bio, &data);
- if (unlikely(!rq))
+ if (unlikely(!rq)) {
+ if (bio_flagged(bio, BIO_NONBLOCKING))
+ bio->bi_error = -EAGAIN;
+ else
+ bio->bi_error = -EIO;
+ bio_endio(bio);
return BLK_QC_T_NONE;
+ }
cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
@@ -1381,8 +1389,14 @@ static blk_qc_t blk_sq_make_request(struct request_queue
*q, struct bio *bio)
request_count = blk_plug_queued_count(q);
rq = blk_mq_map_request(q, bio, &data);
- if (unlikely(!rq))
+ if (unlikely(!rq)) {
+ if (bio_flagged(bio, BIO_NONBLOCKING))
+ bio->bi_error = -EAGAIN;
+ else
+ bio->bi_error = -EIO;
+ bio_endio(bio);
return BLK_QC_T_NONE;
+ }
cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index fb9aa16..9997fed 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -386,6 +386,9 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
else
bio->bi_end_io = dio_bio_end_io;
+ if (dio->iocb->ki_flags & IOCB_NONBLOCKING)
+ bio_set_flag(bio, BIO_NONBLOCKING);
+
sdio->bio = bio;
sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
}
@@ -480,8 +483,12 @@ static int dio_bio_complete(struct dio *dio, struct bio
*bio)
unsigned i;
int err;
- if (bio->bi_error)
- dio->io_error = -EIO;
+ if (bio->bi_error) {
+ if (bio_flagged(bio, BIO_NONBLOCKING))
+ dio->io_error = bio->bi_error;
+ else
+ dio->io_error = -EIO;
+ }
if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty) {
err = bio->bi_error;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index cd395ec..94855cf 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -119,6 +119,7 @@ struct bio {
#define BIO_QUIET 6 /* Make BIO Quiet */
#define BIO_CHAIN 7 /* chained bio, ->bi_remaining in effect */
#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */
+#define BIO_NONBLOCKING 9 /* don't block over blk device congestion */
/*
* Flags starting here get preserved by bio_reset() - this includes
--
2.10.2
