block: Remove zone write locking

Zone write locking is now unused and replaced with zone write plugging.
Remove all code that was implementing zone write locking, that is, the
various helper functions controlling request zone write locking and
the gendisk attached zone bitmaps.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-27-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 4 insertions, 115 deletions

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 60090c8366fb..89ba6b16fe8b 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -54,8 +54,6 @@ typedef __u32 __bitwise req_flags_t;
 /* Look at ->special_vec for the actual data payload instead of the
    bio chain. */
 #define RQF_SPECIAL_PAYLOAD	((__force req_flags_t)(1 << 18))
-/* The per-zone write lock is held for this request */
-#define RQF_ZONE_WRITE_LOCKED	((__force req_flags_t)(1 << 19))
 /* The request completion needs to be signaled to zone write pluging. */
 #define RQF_ZONE_WRITE_PLUGGING	((__force req_flags_t)(1 << 20))
 /* ->timeout has been called, don't expire again */
@@ -1152,85 +1150,4 @@ static inline int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 }
 void blk_dump_rq_flags(struct request *, char *);
 
-#ifdef CONFIG_BLK_DEV_ZONED
-static inline unsigned int blk_rq_zone_no(struct request *rq)
-{
-	return disk_zone_no(rq->q->disk, blk_rq_pos(rq));
-}
-
-static inline unsigned int blk_rq_zone_is_seq(struct request *rq)
-{
-	return disk_zone_is_seq(rq->q->disk, blk_rq_pos(rq));
-}
-
-/**
- * blk_rq_is_seq_zoned_write() - Check if @rq requires write serialization.
- * @rq: Request to examine.
- *
- * Note: REQ_OP_ZONE_APPEND requests do not require serialization.
- */
-static inline bool blk_rq_is_seq_zoned_write(struct request *rq)
-{
-	return op_needs_zoned_write_locking(req_op(rq)) &&
-		blk_rq_zone_is_seq(rq);
-}
-
-bool blk_req_needs_zone_write_lock(struct request *rq);
-bool blk_req_zone_write_trylock(struct request *rq);
-void __blk_req_zone_write_lock(struct request *rq);
-void __blk_req_zone_write_unlock(struct request *rq);
-
-static inline void blk_req_zone_write_lock(struct request *rq)
-{
-	if (blk_req_needs_zone_write_lock(rq))
-		__blk_req_zone_write_lock(rq);
-}
-
-static inline void blk_req_zone_write_unlock(struct request *rq)
-{
-	if (rq->rq_flags & RQF_ZONE_WRITE_LOCKED)
-		__blk_req_zone_write_unlock(rq);
-}
-
-static inline bool blk_req_zone_is_write_locked(struct request *rq)
-{
-	return rq->q->disk->seq_zones_wlock &&
-		test_bit(blk_rq_zone_no(rq), rq->q->disk->seq_zones_wlock);
-}
-
-static inline bool blk_req_can_dispatch_to_zone(struct request *rq)
-{
-	if (!blk_req_needs_zone_write_lock(rq))
-		return true;
-	return !blk_req_zone_is_write_locked(rq);
-}
-#else /* CONFIG_BLK_DEV_ZONED */
-static inline bool blk_rq_is_seq_zoned_write(struct request *rq)
-{
-	return false;
-}
-
-static inline bool blk_req_needs_zone_write_lock(struct request *rq)
-{
-	return false;
-}
-
-static inline void blk_req_zone_write_lock(struct request *rq)
-{
-}
-
-static inline void blk_req_zone_write_unlock(struct request *rq)
-{
-}
-static inline bool blk_req_zone_is_write_locked(struct request *rq)
-{
-	return false;
-}
-
-static inline bool blk_req_can_dispatch_to_zone(struct request *rq)
-{
-	return true;
-}
-#endif /* CONFIG_BLK_DEV_ZONED */
-
 #endif /* BLK_MQ_H */
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index ffe0c112b128..5751292fee6a 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -297,7 +297,6 @@ enum {
 	BIO_QOS_THROTTLED,	/* bio went through rq_qos throttle path */
 	BIO_QOS_MERGED,		/* but went through rq_qos merge path */
 	BIO_REMAPPED,
-	BIO_ZONE_WRITE_LOCKED,	/* Owns a zoned device zone write lock */
 	BIO_ZONE_WRITE_PLUGGING, /* bio handled through zone write plugging */
 	BIO_EMULATES_ZONE_APPEND, /* bio emulates a zone append operation */
 	BIO_FLAG_LAST
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 017e9d064177..7e8a68805324 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -177,23 +177,14 @@ struct gendisk {
 
 #ifdef CONFIG_BLK_DEV_ZONED
 	/*
-	 * Zoned block device information for request dispatch control.
-	 * nr_zones is the total number of zones of the device. This is always
-	 * 0 for regular block devices. conv_zones_bitmap is a bitmap of nr_zones
-	 * bits which indicates if a zone is conventional (bit set) or
-	 * sequential (bit clear). seq_zones_wlock is a bitmap of nr_zones
-	 * bits which indicates if a zone is write locked, that is, if a write
-	 * request targeting the zone was dispatched.
-	 *
-	 * Reads of this information must be protected with blk_queue_enter() /
-	 * blk_queue_exit(). Modifying this information is only allowed while
-	 * no requests are being processed. See also blk_mq_freeze_queue() and
-	 * blk_mq_unfreeze_queue().
+	 * Zoned block device information. Reads of this information must be
+	 * protected with blk_queue_enter() / blk_queue_exit(). Modifying this
+	 * information is only allowed while no requests are being processed.
+	 * See also blk_mq_freeze_queue() and blk_mq_unfreeze_queue().
 	 */
 	unsigned int		nr_zones;
 	unsigned int		zone_capacity;
 	unsigned long		*conv_zones_bitmap;
-	unsigned long		*seq_zones_wlock;
 	unsigned int            zone_wplugs_hash_bits;
 	spinlock_t              zone_wplugs_lock;
 	struct mempool_s	*zone_wplugs_pool;
@@ -635,15 +626,6 @@ static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
 	return sector >> ilog2(disk->queue->limits.chunk_sectors);
 }
 
-static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t sector)
-{
-	if (!blk_queue_is_zoned(disk->queue))
-		return false;
-	if (!disk->conv_zones_bitmap)
-		return true;
-	return !test_bit(disk_zone_no(disk, sector), disk->conv_zones_bitmap);
-}
-
 static inline void disk_set_max_open_zones(struct gendisk *disk,
 		unsigned int max_open_zones)
 {
@@ -677,10 +659,6 @@ static inline unsigned int disk_nr_zones(struct gendisk *disk)
 {
 	return 0;
 }
-static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t sector)
-{
-	return false;
-}
 static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
 {
 	return 0;
@@ -869,11 +847,6 @@ static inline bool bio_straddles_zones(struct bio *bio)
 		disk_zone_no(bio->bi_bdev->bd_disk, bio_end_sector(bio) - 1);
 }
 
-static inline unsigned int bio_zone_is_seq(struct bio *bio)
-{
-	return disk_zone_is_seq(bio->bi_bdev->bd_disk, bio->bi_iter.bi_sector);
-}
-
 /*
  * Return how much of the chunk is left to be used for I/O at a given offset.
  */