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Petersen" , "linux-fsdevel @ vger . kernel . org" , Johannes Thumshirn Subject: [PATCH v6 04/11] block: Introduce REQ_OP_ZONE_APPEND Date: Wed, 15 Apr 2020 18:05:06 +0900 Message-Id: <20200415090513.5133-5-johannes.thumshirn@wdc.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200415090513.5133-1-johannes.thumshirn@wdc.com> References: <20200415090513.5133-1-johannes.thumshirn@wdc.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Keith Busch Define REQ_OP_ZONE_APPEND to append-write sectors to a zone of a zoned block device. This is a no-merge write operation. A zone append write BIO must: * Target a zoned block device * Have a sector position indicating the start sector of the target zone * The target zone must be a sequential write zone * The BIO must not cross a zone boundary * The BIO size must not be split to ensure that a single range of LBAs is written with a single command. Implement these checks in generic_make_request_checks() using the helper function blk_check_zone_append(). To avoid write append BIO splitting, introduce the new max_zone_append_sectors queue limit attribute and ensure that a BIO size is always lower than this limit. Export this new limit through sysfs and check these limits in bio_full(). Also when a LLDD can't dispatch a request to a specific zone, it will return BLK_STS_ZONE_RESOURCE indicating this request needs to be delayed, e.g. because the zone it will be dispatched to is still write-locked. If this happens set the request aside in a local list to continue trying dispatching requests such as READ requests or a WRITE/ZONE_APPEND requests targetting other zones. This way we can still keep a high queue depth without starving other requests even if one request can't be served due to zone write-locking. Finally, make sure that the bio sector position indicates the actual write position as indicated by the device on completion. Signed-off-by: Keith Busch [ jth: added zone-append specific add_page and merge_page helpers ] Signed-off-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Reviewed-by: Daniel Wagner --- block/bio.c | 65 +++++++++++++++++++++++++++++++++++---- block/blk-core.c | 52 +++++++++++++++++++++++++++++++ block/blk-mq.c | 27 ++++++++++++++++ block/blk-settings.c | 23 ++++++++++++++ block/blk-sysfs.c | 13 ++++++++ drivers/scsi/scsi_lib.c | 1 + include/linux/blk_types.h | 14 +++++++++ include/linux/blkdev.h | 11 +++++++ 8 files changed, 200 insertions(+), 6 deletions(-) diff --git a/block/bio.c b/block/bio.c index 0f0e337e46b4..ba10076ced9c 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1000,13 +1000,12 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) struct page *page = pages[i]; len = min_t(size_t, PAGE_SIZE - offset, left); - if (__bio_try_merge_page(bio, page, len, offset, &same_page)) { if (same_page) put_page(page); } else { if (WARN_ON_ONCE(bio_full(bio, len))) - return -EINVAL; + return -EINVAL; __bio_add_page(bio, page, len, offset); } offset = 0; @@ -1016,6 +1015,50 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) return 0; } +static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter) +{ + unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt; + unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt; + struct request_queue *q = bio->bi_disk->queue; + unsigned int max_append_sectors = queue_max_zone_append_sectors(q); + struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; + struct page **pages = (struct page **)bv; + ssize_t size, left; + unsigned len, i; + size_t offset; + + if (WARN_ON_ONCE(!max_append_sectors)) + return 0; + + /* + * Move page array up in the allocated memory for the bio vecs as far as + * possible so that we can start filling biovecs from the beginning + * without overwriting the temporary page array. + */ + BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); + pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); + + size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); + if (unlikely(size <= 0)) + return size ? size : -EFAULT; + + for (left = size, i = 0; left > 0; left -= len, i++) { + struct page *page = pages[i]; + bool same_page = false; + + len = min_t(size_t, PAGE_SIZE - offset, left); + if (bio_add_hw_page(q, bio, page, len, offset, + max_append_sectors, &same_page) != len) + return -EINVAL; + if (same_page) + put_page(page); + offset = 0; + } + + iov_iter_advance(iter, size); + return 0; +} + /** * bio_iov_iter_get_pages - add user or kernel pages to a bio * @bio: bio to add pages to @@ -1045,10 +1088,16 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) return -EINVAL; do { - if (is_bvec) - ret = __bio_iov_bvec_add_pages(bio, iter); - else - ret = __bio_iov_iter_get_pages(bio, iter); + if (bio_op(bio) == REQ_OP_ZONE_APPEND) { + if (WARN_ON_ONCE(is_bvec)) + return -EINVAL; + ret = __bio_iov_append_get_pages(bio, iter); + } else { + if (is_bvec) + ret = __bio_iov_bvec_add_pages(bio, iter); + else + ret = __bio_iov_iter_get_pages(bio, iter); + } } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); if (is_bvec) @@ -1451,6 +1500,10 @@ struct bio *bio_split(struct bio *bio, int sectors, BUG_ON(sectors <= 0); BUG_ON(sectors >= bio_sectors(bio)); + /* Zone append commands cannot be split */ + if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND)) + return NULL; + split = bio_clone_fast(bio, gfp, bs); if (!split) return NULL; diff --git a/block/blk-core.c b/block/blk-core.c index 7e4a1da0715e..34fe47a728c3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -135,6 +135,7 @@ static const char *const blk_op_name[] = { REQ_OP_NAME(ZONE_OPEN), REQ_OP_NAME(ZONE_CLOSE), REQ_OP_NAME(ZONE_FINISH), + REQ_OP_NAME(ZONE_APPEND), REQ_OP_NAME(WRITE_SAME), REQ_OP_NAME(WRITE_ZEROES), REQ_OP_NAME(SCSI_IN), @@ -240,6 +241,17 @@ static void req_bio_endio(struct request *rq, struct bio *bio, bio_advance(bio, nbytes); + if (req_op(rq) == REQ_OP_ZONE_APPEND && error == BLK_STS_OK) { + /* + * Partial zone append completions cannot be supported as the + * BIO fragments may end up not being written sequentially. + */ + if (bio->bi_iter.bi_size) + bio->bi_status = BLK_STS_IOERR; + else + bio->bi_iter.bi_sector = rq->__sector; + } + /* don't actually finish bio if it's part of flush sequence */ if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) bio_endio(bio); @@ -871,6 +883,41 @@ static inline int blk_partition_remap(struct bio *bio) return ret; } +/* + * Check write append to a zoned block device. + */ +static inline blk_status_t blk_check_zone_append(struct request_queue *q, + struct bio *bio) +{ + sector_t pos = bio->bi_iter.bi_sector; + int nr_sectors = bio_sectors(bio); + + /* Only applicable to zoned block devices */ + if (!blk_queue_is_zoned(q)) + return BLK_STS_NOTSUPP; + + /* The bio sector must point to the start of a sequential zone */ + if (pos & (blk_queue_zone_sectors(q) - 1) || + !blk_queue_zone_is_seq(q, pos)) + return BLK_STS_IOERR; + + /* + * Not allowed to cross zone boundaries. Otherwise, the BIO will be + * split and could result in non-contiguous sectors being written in + * different zones. + */ + if (blk_queue_zone_no(q, pos) != blk_queue_zone_no(q, pos + nr_sectors)) + return BLK_STS_IOERR; + + /* Make sure the BIO is small enough and will not get split */ + if (nr_sectors > q->limits.max_zone_append_sectors) + return BLK_STS_IOERR; + + bio->bi_opf |= REQ_NOMERGE; + + return BLK_STS_OK; +} + static noinline_for_stack bool generic_make_request_checks(struct bio *bio) { @@ -943,6 +990,11 @@ generic_make_request_checks(struct bio *bio) if (!q->limits.max_write_same_sectors) goto not_supported; break; + case REQ_OP_ZONE_APPEND: + status = blk_check_zone_append(q, bio); + if (status != BLK_STS_OK) + goto end_io; + break; case REQ_OP_ZONE_RESET: case REQ_OP_ZONE_OPEN: case REQ_OP_ZONE_CLOSE: diff --git a/block/blk-mq.c b/block/blk-mq.c index 8e56884fd2e9..50e216a218ee 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1195,6 +1195,19 @@ static void blk_mq_handle_dev_resource(struct request *rq, __blk_mq_requeue_request(rq); } +static void blk_mq_handle_zone_resource(struct request *rq, + struct list_head *zone_list) +{ + /* + * If we end up here it is because we cannot dispatch a request to a + * specific zone due to LLD level zone-write locking or other zone + * related resource not being available. In this case, set the request + * aside in zone_list for retrying it later. + */ + list_add(&rq->queuelist, zone_list); + __blk_mq_requeue_request(rq); +} + /* * Returns true if we did some work AND can potentially do more. */ @@ -1206,6 +1219,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, bool no_tag = false; int errors, queued; blk_status_t ret = BLK_STS_OK; + LIST_HEAD(zone_list); if (list_empty(list)) return false; @@ -1264,6 +1278,16 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { blk_mq_handle_dev_resource(rq, list); break; + } else if (ret == BLK_STS_ZONE_RESOURCE) { + /* + * Move the request to zone_list and keep going through + * the dispatch list to find more requests the drive can + * accept. + */ + blk_mq_handle_zone_resource(rq, &zone_list); + if (list_empty(list)) + break; + continue; } if (unlikely(ret != BLK_STS_OK)) { @@ -1275,6 +1299,9 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, queued++; } while (!list_empty(list)); + if (!list_empty(&zone_list)) + list_splice_tail_init(&zone_list, list); + hctx->dispatched[queued_to_index(queued)]++; /* diff --git a/block/blk-settings.c b/block/blk-settings.c index 14397b4c4b53..58d5b49fb131 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -48,6 +48,7 @@ void blk_set_default_limits(struct queue_limits *lim) lim->chunk_sectors = 0; lim->max_write_same_sectors = 0; lim->max_write_zeroes_sectors = 0; + lim->max_zone_append_sectors = 0; lim->max_discard_sectors = 0; lim->max_hw_discard_sectors = 0; lim->discard_granularity = 0; @@ -83,6 +84,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_dev_sectors = UINT_MAX; lim->max_write_same_sectors = UINT_MAX; lim->max_write_zeroes_sectors = UINT_MAX; + lim->max_zone_append_sectors = UINT_MAX; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -221,6 +223,25 @@ void blk_queue_max_write_zeroes_sectors(struct request_queue *q, } EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors); +/** + * blk_queue_max_zone_append_sectors - set max sectors for a single zone append + * @q: the request queue for the device + * @max_zone_append_sectors: maximum number of sectors to write per command + **/ +void blk_queue_max_zone_append_sectors(struct request_queue *q, + unsigned int max_zone_append_sectors) +{ + unsigned int max_sectors; + + max_sectors = min(q->limits.max_hw_sectors, max_zone_append_sectors); + if (max_sectors) + max_sectors = min_not_zero(q->limits.chunk_sectors, + max_sectors); + + q->limits.max_zone_append_sectors = max_sectors; +} +EXPORT_SYMBOL_GPL(blk_queue_max_zone_append_sectors); + /** * blk_queue_max_segments - set max hw segments for a request for this queue * @q: the request queue for the device @@ -470,6 +491,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, b->max_write_same_sectors); t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, b->max_write_zeroes_sectors); + t->max_zone_append_sectors = min(t->max_zone_append_sectors, + b->max_zone_append_sectors); t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index fca9b158f4a0..02643e149d5e 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -218,6 +218,13 @@ static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page) (unsigned long long)q->limits.max_write_zeroes_sectors << 9); } +static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page) +{ + unsigned long long max_sectors = q->limits.max_zone_append_sectors; + + return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT); +} + static ssize_t queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) { @@ -639,6 +646,11 @@ static struct queue_sysfs_entry queue_write_zeroes_max_entry = { .show = queue_write_zeroes_max_show, }; +static struct queue_sysfs_entry queue_zone_append_max_entry = { + .attr = {.name = "zone_append_max_bytes", .mode = 0444 }, + .show = queue_zone_append_max_show, +}; + static struct queue_sysfs_entry queue_nonrot_entry = { .attr = {.name = "rotational", .mode = 0644 }, .show = queue_show_nonrot, @@ -749,6 +761,7 @@ static struct attribute *queue_attrs[] = { &queue_discard_zeroes_data_entry.attr, &queue_write_same_max_entry.attr, &queue_write_zeroes_max_entry.attr, + &queue_zone_append_max_entry.attr, &queue_nonrot_entry.attr, &queue_zoned_entry.attr, &queue_nr_zones_entry.attr, diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index ad97369ffabd..b9e8f55cf8c4 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1690,6 +1690,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, case BLK_STS_OK: break; case BLK_STS_RESOURCE: + case BLK_STS_ZONE_RESOURCE: if (atomic_read(&sdev->device_busy) || scsi_device_blocked(sdev)) ret = BLK_STS_DEV_RESOURCE; diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 70254ae11769..824ec2d89954 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -63,6 +63,18 @@ typedef u8 __bitwise blk_status_t; */ #define BLK_STS_DEV_RESOURCE ((__force blk_status_t)13) +/* + * BLK_STS_ZONE_RESOURCE is returned from the driver to the block layer if zone + * related resources are unavailable, but the driver can guarantee the queue + * will be rerun in the future once the resources become available again. + * + * This is different from BLK_STS_DEV_RESOURCE in that it explicitly references + * a zone specific resource and IO to a different zone on the same device could + * still be served. Examples of that are zones that are write-locked, but a read + * to the same zone could be served. + */ +#define BLK_STS_ZONE_RESOURCE ((__force blk_status_t)14) + /** * blk_path_error - returns true if error may be path related * @error: status the request was completed with @@ -296,6 +308,8 @@ enum req_opf { REQ_OP_ZONE_CLOSE = 11, /* Transition a zone to full */ REQ_OP_ZONE_FINISH = 12, + /* write data at the current zone write pointer */ + REQ_OP_ZONE_APPEND = 13, /* SCSI passthrough using struct scsi_request */ REQ_OP_SCSI_IN = 32, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index e47888a7d80b..774947365341 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -336,6 +336,7 @@ struct queue_limits { unsigned int max_hw_discard_sectors; unsigned int max_write_same_sectors; unsigned int max_write_zeroes_sectors; + unsigned int max_zone_append_sectors; unsigned int discard_granularity; unsigned int discard_alignment; @@ -757,6 +758,9 @@ static inline bool rq_mergeable(struct request *rq) if (req_op(rq) == REQ_OP_WRITE_ZEROES) return false; + if (req_op(rq) == REQ_OP_ZONE_APPEND) + return false; + if (rq->cmd_flags & REQ_NOMERGE_FLAGS) return false; if (rq->rq_flags & RQF_NOMERGE_FLAGS) @@ -1091,6 +1095,8 @@ extern void blk_queue_max_write_same_sectors(struct request_queue *q, extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q, unsigned int max_write_same_sectors); extern void blk_queue_logical_block_size(struct request_queue *, unsigned int); +extern void blk_queue_max_zone_append_sectors(struct request_queue *q, + unsigned int max_zone_append_sectors); extern void blk_queue_physical_block_size(struct request_queue *, unsigned int); extern void blk_queue_alignment_offset(struct request_queue *q, unsigned int alignment); @@ -1303,6 +1309,11 @@ static inline unsigned int queue_max_segment_size(const struct request_queue *q) return q->limits.max_segment_size; } +static inline unsigned int queue_max_zone_append_sectors(const struct request_queue *q) +{ + return q->limits.max_zone_append_sectors; +} + static inline unsigned queue_logical_block_size(const struct request_queue *q) { int retval = 512;