[PATCH v8 1/9] block: Introduce more member variables related to zone write locking
From: Bart Van Assche <bvanassche@acm.org>
Date: 2023-08-11 21:36:13
Also in:
linux-scsi
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Many but not all storage controllers require serialization of zoned writes. Introduce a new request queue limit member variable (driver_preserves_write_order) that allows block drivers to indicate that the order of write commands is preserved and hence that serialization of writes per zone is not required. Make disk_set_zoned() set 'use_zone_write_lock' 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 | 7 +++++++ include/linux/blkdev.h | 10 ++++++++++ 2 files changed, 17 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 0046b447268f..3a7748af1bef 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;
@@ -685,6 +687,9 @@ 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); + /* Request-based stacking drivers do not reorder requests. */ + t->driver_preserves_write_order = b->driver_preserves_write_order; + t->use_zone_write_lock = b->use_zone_write_lock; t->zoned = max(t->zoned, b->zoned); return ret; }
@@ -949,6 +954,8 @@ void disk_set_zoned(struct gendisk *disk, enum blk_zoned_model model) } q->limits.zoned = model; + 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/include/linux/blkdev.h b/include/linux/blkdev.h
index 2f5371b8482c..2c090a28ec78 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; /*