[5/8] nowait aio: return on congested block device

Message ID	20170414120257.8932-6-rgoldwyn@suse.de (mailing list archive)
State	Not Applicable
Headers	show Return-Path: <linux-btrfs-owner@kernel.org> From: Goldwyn Rodrigues <rgoldwyn@suse.de> To: linux-fsdevel@vger.kernel.org Cc: jack@suse.com, hch@infradead.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, sagi@grimberg.me, avi@scylladb.com, axboe@kernel.dk, linux-api@vger.kernel.org, willy@infradead.org, tom.leiming@gmail.com, Goldwyn Rodrigues <rgoldwyn@suse.com> Subject: [PATCH 5/8] nowait aio: return on congested block device Date: Fri, 14 Apr 2017 07:02:54 -0500 Message-Id: <20170414120257.8932-6-rgoldwyn@suse.de> In-Reply-To: <20170414120257.8932-1-rgoldwyn@suse.de> References: <20170414120257.8932-1-rgoldwyn@suse.de> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk

diff --git a/block/blk-core.c b/block/blk-core.c index d772c221cc17..54698521756b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1232,6 +1232,11 @@ static struct request *get_request(struct request_queue *q, unsigned int op, if (!IS_ERR(rq)) return rq; + if (bio && (bio->bi_opf & 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; @@ -1870,6 +1875,18 @@ generic_make_request_checks(struct bio *bio) goto end_io; } + if (bio->bi_opf & REQ_NOWAIT) { + if (!blk_queue_nowait(q)) { + err = -EOPNOTSUPP; + goto end_io; + } + if (!(bio->bi_opf & REQ_SYNC)) { + err = -EINVAL; + goto end_io; + } + } + + part = bio->bi_bdev->bd_part; if (should_fail_request(part, bio->bi_iter.bi_size) || should_fail_request(&part_to_disk(part)->part0, @@ -2021,7 +2038,7 @@ 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 */ @@ -2046,7 +2063,10 @@ 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); diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index c974a1bbf4cb..9f88190ff395 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -119,6 +119,9 @@ struct request *blk_mq_sched_get_request(struct request_queue *q, if (likely(!data->hctx)) data->hctx = blk_mq_map_queue(q, data->ctx->cpu); + if (bio && (bio->bi_opf & REQ_NOWAIT)) + data->flags |= BLK_MQ_REQ_NOWAIT; + if (e) { data->flags |= BLK_MQ_REQ_INTERNAL; diff --git a/block/blk-mq.c b/block/blk-mq.c index 572966f49596..8b9b1a411ce2 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1538,6 +1538,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data); if (unlikely(!rq)) { __wbt_done(q->rq_wb, wb_acct); + if (bio && (bio->bi_opf & REQ_NOWAIT)) + bio_wouldblock_error(bio); return BLK_QC_T_NONE; } @@ -1662,6 +1664,8 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio) rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data); if (unlikely(!rq)) { __wbt_done(q->rq_wb, wb_acct); + if (bio && (bio->bi_opf & REQ_NOWAIT)) + bio_wouldblock_error(bio); return BLK_QC_T_NONE; } diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 1d4c9f8bc1e1..7481124c5025 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -731,6 +731,9 @@ static int virtblk_probe(struct virtio_device *vdev) /* No real sector limit. */ blk_queue_max_hw_sectors(q, -1U); + /* Request queue supports BIO_NOWAIT */ + queue_flag_set_unlocked(QUEUE_FLAG_NOWAIT, q); + /* Host can optionally specify maximum segment size and number of * segments. */ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index fcfeddc79331..9df85ee165be 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3177,6 +3177,9 @@ static int sd_probe(struct device *dev) SD_MOD_TIMEOUT); } + /* Support BIO_NOWAIT */ + queue_flag_set_unlocked(QUEUE_FLAG_NOWAIT, sdp->request_queue); + device_initialize(&sdkp->dev); sdkp->dev.parent = dev; sdkp->dev.class = &sd_disk_class; diff --git a/fs/direct-io.c b/fs/direct-io.c index a04ebea77de8..a802168284e1 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -480,8 +480,12 @@ 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->bi_opf & REQ_NOWAIT) + dio->io_error = -EAGAIN; + else + dio->io_error = -EIO; + } if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty) { err = bio->bi_error; @@ -1197,6 +1201,8 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, if (iov_iter_rw(iter) == WRITE) { dio->op = REQ_OP_WRITE; dio->op_flags = REQ_SYNC | REQ_IDLE; + if (iocb->ki_flags & IOCB_NOWAIT) + dio->op_flags |= REQ_NOWAIT; } else { dio->op = REQ_OP_READ; } diff --git a/include/linux/bio.h b/include/linux/bio.h index 8e521194f6fc..1a9270744b1e 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -425,6 +425,12 @@ static inline void bio_io_error(struct bio *bio) bio_endio(bio); } +static inline void bio_wouldblock_error(struct bio *bio) +{ + bio->bi_error = -EAGAIN; + bio_endio(bio); +} + struct request_queue; extern int bio_phys_segments(struct request_queue *, struct bio *); diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index d703acb55d0f..5ce4da30ba43 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -187,6 +187,7 @@ enum req_flag_bits { __REQ_PREFLUSH, /* request for cache flush */ __REQ_RAHEAD, /* read ahead, can fail anytime */ __REQ_BACKGROUND, /* background IO */ + __REQ_NOWAIT, /* Don't wait if request will block */ __REQ_NR_BITS, /* stops here */ }; @@ -203,6 +204,7 @@ enum req_flag_bits { #define REQ_PREFLUSH (1ULL << __REQ_PREFLUSH) #define REQ_RAHEAD (1ULL << __REQ_RAHEAD) #define REQ_BACKGROUND (1ULL << __REQ_BACKGROUND) +#define REQ_NOWAIT (1ULL << __REQ_NOWAIT) #define REQ_FAILFAST_MASK \ (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 7548f332121a..df0b1245d955 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -610,6 +610,8 @@ struct request_queue { #define QUEUE_FLAG_FLUSH_NQ 25 /* flush not queueuable */ #define QUEUE_FLAG_DAX 26 /* device supports DAX */ #define QUEUE_FLAG_STATS 27 /* track rq completion times */ +/* can return immediately on congestion (for REQ_NOWAIT) */ +#define QUEUE_FLAG_NOWAIT 28 #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ @@ -700,6 +702,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) #define blk_queue_secure_erase(q) \ (test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags)) #define blk_queue_dax(q) test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags) +#define blk_queue_nowait(q) test_bit(QUEUE_FLAG_NOWAIT, &(q)->queue_flags) #define blk_noretry_request(rq) \ ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \

[5/8] nowait aio: return on congested block device

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