From ccdbf0aad2523ca133cceb22ce0f8306730e7ac3 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Mon, 8 Apr 2024 10:41:09 +0900 Subject: block: Allow zero value of max_zone_append_sectors queue limit In preparation for adding a generic zone append emulation using zone write plugging, allow device drivers supporting zoned block device to set a the max_zone_append_sectors queue limit of a device to 0 to indicate the lack of native support for zone append operations and that the block layer should emulate these operations using regular write operations. blk_queue_max_zone_append_sectors() is modified to allow passing 0 as the max_zone_append_sectors argument. The function queue_max_zone_append_sectors() is also modified to ensure that the minimum of the max_hw_sectors and chunk_sectors limit is used whenever the max_zone_append_sectors limit is 0. This minimum is consistent with the value set for the max_zone_append_sectors limit by the function blk_validate_zoned_limits() when limits for a queue are validated. The helper functions queue_emulates_zone_append() and bdev_emulates_zone_append() are added to test if a queue (or block device) emulates zone append operations. In order for blk_revalidate_disk_zones() to accept zoned block devices relying on zone append emulation, the direct check to the max_zone_append_sectors queue limit of the disk is replaced by a check using the value returned by queue_max_zone_append_sectors(). Similarly, queue_zone_append_max_show() is modified to use the same accessor so that the sysfs attribute advertizes the non-zero limit that will be used, regardless if it is for native or emulated commands. For stacking drivers, a top device should not need to care if the underlying devices have native or emulated zone append operations. blk_stack_limits() is thus modified to set the top device max_zone_append_sectors limit using the new accessor queue_limits_max_zone_append_sectors(). queue_max_zone_append_sectors() is modified to use this function as well. Stacking drivers that require zone append emulation, e.g. dm-crypt, can still request this feature by calling blk_queue_max_zone_append_sectors() with a 0 limit. Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Bart Van Assche Tested-by: Hans Holmberg Tested-by: Dennis Maisenbacher Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20240408014128.205141-10-dlemoal@kernel.org Signed-off-by: Jens Axboe --- block/blk-settings.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) (limited to 'block/blk-settings.c') diff --git a/block/blk-settings.c b/block/blk-settings.c index cdbaef159c4b..c0197e1e7485 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -412,24 +412,32 @@ 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 + * + * Sets the maximum number of sectors allowed for zone append commands. If + * Specifying 0 for @max_zone_append_sectors indicates that the queue does + * not natively support zone append operations and that the block layer must + * emulate these operations using regular writes. **/ void blk_queue_max_zone_append_sectors(struct request_queue *q, unsigned int max_zone_append_sectors) { - unsigned int max_sectors; + unsigned int max_sectors = 0; if (WARN_ON(!blk_queue_is_zoned(q))) return; - max_sectors = min(q->limits.max_hw_sectors, max_zone_append_sectors); - max_sectors = min(q->limits.chunk_sectors, max_sectors); + if (max_zone_append_sectors) { + max_sectors = min(q->limits.max_hw_sectors, + max_zone_append_sectors); + max_sectors = min(q->limits.chunk_sectors, max_sectors); - /* - * Signal eventual driver bugs resulting in the max_zone_append sectors limit - * being 0 due to a 0 argument, the chunk_sectors limit (zone size) not set, - * or the max_hw_sectors limit not set. - */ - WARN_ON(!max_sectors); + /* + * Signal eventual driver bugs resulting in the max_zone_append + * sectors limit being 0 due to the chunk_sectors limit (zone + * size) not set or the max_hw_sectors limit not set. + */ + WARN_ON_ONCE(!max_sectors); + } q->limits.max_zone_append_sectors = max_sectors; } @@ -756,8 +764,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_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->max_zone_append_sectors = min(queue_limits_max_zone_append_sectors(t), + queue_limits_max_zone_append_sectors(b)); t->bounce = max(t->bounce, b->bounce); t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, -- cgit v1.2.3