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author | Keith Busch <kbusch@kernel.org> | 2020-05-12 17:55:47 +0900 |
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committer | Jens Axboe <axboe@kernel.dk> | 2020-05-12 20:36:28 -0600 |
commit | 0512a75b98f847c2e9a4b664013424e603e202f7 (patch) | |
tree | 06cfd06a4bc26fb345a3afb40fa0fa58ba54062c /include | |
parent | e4581105771b3523ced88f781eb2672195d217aa (diff) | |
download | lwn-0512a75b98f847c2e9a4b664013424e603e202f7.tar.gz lwn-0512a75b98f847c2e9a4b664013424e603e202f7.zip |
block: Introduce REQ_OP_ZONE_APPEND
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 <kbusch@kernel.org>
[ jth: added zone-append specific add_page and merge_page helpers ]
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/blk_types.h | 14 | ||||
-rw-r--r-- | include/linux/blkdev.h | 11 |
2 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 90895d594e64..b90dca1fa430 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 d736acf7f564..5647c78bb876 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -332,6 +332,7 @@ 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; @@ -750,6 +751,9 @@ 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) @@ -1084,6 +1088,8 @@ 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); @@ -1301,6 +1307,11 @@ 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; |