[PATCH v9 01/17] block: Introduce more member variables related to zone write locking
From: Bart Van Assche <bvanassche@acm.org>
Date: 2023-08-16 19:55:53
Also in:
linux-scsi
Subsystem:
block layer, the rest, zoned block device (block layer) · Maintainers:
Jens Axboe, Linus Torvalds, Damien Le Moal
Many but not all storage controllers require serialization of zoned writes. Introduce two new request queue limit member variables related to write serialization. 'driver_preserves_write_order' allows block drivers to indicate that the order of write commands is preserved and hence that serialization of writes per zone is not required. 'use_zone_write_lock' is set by disk_set_zoned() if and only if the block device has zones and if the block driver does not preserve the order of write requests. Cc: Damien Le Moal <dlemoal@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <redacted> Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- block/blk-settings.c | 15 +++++++++++++++ block/blk-zoned.c | 1 + include/linux/blkdev.h | 10 ++++++++++ 3 files changed, 26 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 0046b447268f..4c776c08f190 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c@@ -56,6 +56,8 @@ void blk_set_default_limits(struct queue_limits *lim) lim->alignment_offset = 0; lim->io_opt = 0; lim->misaligned = 0; + lim->driver_preserves_write_order = false; + lim->use_zone_write_lock = false; lim->zoned = BLK_ZONED_NONE; lim->zone_write_granularity = 0; lim->dma_alignment = 511;
@@ -82,6 +84,8 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_dev_sectors = UINT_MAX; lim->max_write_zeroes_sectors = UINT_MAX; lim->max_zone_append_sectors = UINT_MAX; + /* Request-based stacking drivers do not reorder requests. */ + lim->driver_preserves_write_order = true; } EXPORT_SYMBOL(blk_set_stacking_limits);
@@ -685,6 +689,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, b->max_secure_erase_sectors); t->zone_write_granularity = max(t->zone_write_granularity, b->zone_write_granularity); + t->driver_preserves_write_order = t->driver_preserves_write_order && + b->driver_preserves_write_order; + t->use_zone_write_lock = t->use_zone_write_lock || + b->use_zone_write_lock; t->zoned = max(t->zoned, b->zoned); return ret; }
@@ -949,6 +957,13 @@ void disk_set_zoned(struct gendisk *disk, enum blk_zoned_model model) } q->limits.zoned = model; + /* + * Use the zone write lock only for zoned block devices and only if + * the block driver does not preserve the order of write commands. + */ + q->limits.use_zone_write_lock = model != BLK_ZONED_NONE && + !q->limits.driver_preserves_write_order; + if (model != BLK_ZONED_NONE) { /* * Set the zone write granularity to the device logical block
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 619ee41a51cc..112620985bff 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c@@ -631,6 +631,7 @@ void disk_clear_zone_settings(struct gendisk *disk) q->limits.chunk_sectors = 0; q->limits.zone_write_granularity = 0; q->limits.max_zone_append_sectors = 0; + q->limits.use_zone_write_lock = false; blk_mq_unfreeze_queue(q); }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4feed1fc141f..e6d5450c8488 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h@@ -316,6 +316,16 @@ struct queue_limits { unsigned char misaligned; unsigned char discard_misaligned; unsigned char raid_partial_stripes_expensive; + /* + * Whether or not the block driver preserves the order of write + * requests. Set by the block driver. + */ + bool driver_preserves_write_order; + /* + * Whether or not zone write locking should be used. Set by + * disk_set_zoned(). + */ + bool use_zone_write_lock; enum blk_zoned_model zoned; /*