From ccdbf0aad2523ca133cceb22ce0f8306730e7ac3 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Mon, 8 Apr 2024 10:41:09 +0900 Subject: [PATCH] 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-core.c | 2 +- block/blk-settings.c | 30 +++++++++++++++++++----------- block/blk-sysfs.c | 2 +- block/blk-zoned.c | 2 +- include/linux/blkdev.h | 23 ++++++++++++++++++++--- 5 files changed, 42 insertions(+), 17 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index a16b5abdbbf5..3bf28149e104 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -602,7 +602,7 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q, return BLK_STS_IOERR; /* Make sure the BIO is small enough and will not get split */ - if (nr_sectors > q->limits.max_zone_append_sectors) + if (nr_sectors > queue_max_zone_append_sectors(q)) return BLK_STS_IOERR; bio->bi_opf |= REQ_NOMERGE; 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, diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 8c8f69d8ba48..e3ed5a921aff 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -224,7 +224,7 @@ static ssize_t queue_zone_write_granularity_show(struct request_queue *q, static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page) { - unsigned long long max_sectors = q->limits.max_zone_append_sectors; + unsigned long long max_sectors = queue_max_zone_append_sectors(q); return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT); } diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 4b21a1ec00d4..fcc1284b7c19 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -1692,7 +1692,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk, return -ENODEV; } - if (!q->limits.max_zone_append_sectors) { + if (!queue_max_zone_append_sectors(q)) { pr_warn("%s: Invalid 0 maximum zone append limit\n", disk->disk_name); return -ENODEV; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 348b57ca0425..46613bf6a402 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1173,12 +1173,29 @@ 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) +static inline unsigned int queue_limits_max_zone_append_sectors(struct queue_limits *l) { + unsigned int max_sectors = min(l->chunk_sectors, l->max_hw_sectors); - const struct queue_limits *l = &q->limits; + return min_not_zero(l->max_zone_append_sectors, max_sectors); +} - return min(l->max_zone_append_sectors, l->max_sectors); +static inline unsigned int queue_max_zone_append_sectors(struct request_queue *q) +{ + if (!blk_queue_is_zoned(q)) + return 0; + + return queue_limits_max_zone_append_sectors(&q->limits); +} + +static inline bool queue_emulates_zone_append(struct request_queue *q) +{ + return blk_queue_is_zoned(q) && !q->limits.max_zone_append_sectors; +} + +static inline bool bdev_emulates_zone_append(struct block_device *bdev) +{ + return queue_emulates_zone_append(bdev_get_queue(bdev)); } static inline unsigned int