From c9c77418a98273fe96835c42666f7427b3883f48 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 5 Jan 2023 12:51:46 -0800 Subject: [PATCH] block: save user max_sectors limit The user can set the max_sectors limit to any valid value via sysfs /sys/block//queue/max_sectors_kb attribute. If the device limits are ever rescanned, though, the limit reverts back to the potentially artificially low BLK_DEF_MAX_SECTORS value. Preserve the user's setting as the max_sectors limit as long as it's valid. The user can reset back to defaults by writing 0 to the sysfs file. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20230105205146.3610282-3-kbusch@meta.com Signed-off-by: Jens Axboe --- Documentation/ABI/stable/sysfs-block | 3 ++- block/blk-settings.c | 9 +++++++-- block/blk-sysfs.c | 21 +++++++++++++++------ include/linux/blkdev.h | 1 + 4 files changed, 25 insertions(+), 9 deletions(-) diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block index cd14ecb..ac1e519 100644 --- a/Documentation/ABI/stable/sysfs-block +++ b/Documentation/ABI/stable/sysfs-block @@ -432,7 +432,8 @@ Contact: linux-block@vger.kernel.org Description: [RW] This is the maximum number of kilobytes that the block layer will allow for a filesystem request. Must be smaller than - or equal to the maximum size allowed by the hardware. + or equal to the maximum size allowed by the hardware. Write 0 + to use default kernel settings. What: /sys/block//queue/max_segment_size diff --git a/block/blk-settings.c b/block/blk-settings.c index 9875ca1..9c9713c 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -40,7 +40,7 @@ void blk_set_default_limits(struct queue_limits *lim) lim->virt_boundary_mask = 0; lim->max_segment_size = BLK_MAX_SEGMENT_SIZE; lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS; - lim->max_dev_sectors = 0; + lim->max_user_sectors = lim->max_dev_sectors = 0; lim->chunk_sectors = 0; lim->max_write_zeroes_sectors = 0; lim->max_zone_append_sectors = 0; @@ -135,7 +135,12 @@ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto limits->max_hw_sectors = max_hw_sectors; max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors); - max_sectors = min(max_sectors, BLK_DEF_MAX_SECTORS); + + if (limits->max_user_sectors) + max_sectors = min(max_sectors, limits->max_user_sectors); + else + max_sectors = min(max_sectors, BLK_DEF_MAX_SECTORS); + max_sectors = round_down(max_sectors, limits->logical_block_size >> SECTOR_SHIFT); limits->max_sectors = max_sectors; diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 93d9e9c..5486b6c 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -239,19 +239,28 @@ static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page) static ssize_t queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) { - unsigned long max_sectors_kb, + unsigned long var; + unsigned int max_sectors_kb, max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1, page_kb = 1 << (PAGE_SHIFT - 10); - ssize_t ret = queue_var_store(&max_sectors_kb, page, count); + ssize_t ret = queue_var_store(&var, page, count); if (ret < 0) return ret; - max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long) + max_sectors_kb = (unsigned int)var; + max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, q->limits.max_dev_sectors >> 1); - - if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) - return -EINVAL; + if (max_sectors_kb == 0) { + q->limits.max_user_sectors = 0; + max_sectors_kb = min(max_hw_sectors_kb, + BLK_DEF_MAX_SECTORS >> 1); + } else { + if (max_sectors_kb > max_hw_sectors_kb || + max_sectors_kb < page_kb) + return -EINVAL; + q->limits.max_user_sectors = max_sectors_kb << 1; + } spin_lock_irq(&q->queue_lock); q->limits.max_sectors = max_sectors_kb << 1; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 2b85161..b87ed82 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -288,6 +288,7 @@ struct queue_limits { unsigned int max_dev_sectors; unsigned int chunk_sectors; unsigned int max_sectors; + unsigned int max_user_sectors; unsigned int max_segment_size; unsigned int physical_block_size; unsigned int logical_block_size; -- 2.7.4