From ca369d51b3e1649be4a72addd6d6a168cfb3f537 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Fri, 13 Nov 2015 16:46:48 -0500 Subject: block/sd: Fix device-imposed transfer length limits Commit 4f258a46346c ("sd: Fix maximum I/O size for BLOCK_PC requests") had the unfortunate side-effect of removing an implicit clamp to BLK_DEF_MAX_SECTORS for REQ_TYPE_FS requests in the block layer code. This caused problems for some SMR drives. Debugging this issue revealed a few problems with the existing infrastructure since the block layer didn't know how to deal with device-imposed limits, only limits set by the I/O controller. - Introduce a new queue limit, max_dev_sectors, which is used by the ULD to signal the maximum sectors for a REQ_TYPE_FS request. - Ensure that max_dev_sectors is correctly stacked and taken into account when overriding max_sectors through sysfs. - Rework sd_read_block_limits() so it saves the max_xfer and opt_xfer values for later processing. - In sd_revalidate() set the queue's max_dev_sectors based on the MAXIMUM TRANSFER LENGTH value in the Block Limits VPD. If this value is not reported, fall back to a cap based on the CDB TRANSFER LENGTH field size. - In sd_revalidate(), use OPTIMAL TRANSFER LENGTH from the Block Limits VPD--if reported and sane--to signal the preferred device transfer size for FS requests. Otherwise use BLK_DEF_MAX_SECTORS. - blk_limits_max_hw_sectors() is no longer used and can be removed. Signed-off-by: Martin K. Petersen Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93581 Reviewed-by: Christoph Hellwig Tested-by: sweeneygj@gmx.com Tested-by: Arzeets Tested-by: David Eisner Tested-by: Mario Kicherer Signed-off-by: Martin K. Petersen --- block/blk-settings.c | 36 ++++++++++++++++-------------------- block/blk-sysfs.c | 3 +++ 2 files changed, 19 insertions(+), 20 deletions(-) (limited to 'block') diff --git a/block/blk-settings.c b/block/blk-settings.c index 7d8f129a1516..dd4973583978 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -91,7 +91,8 @@ void blk_set_default_limits(struct queue_limits *lim) lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; 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_sectors = lim->max_dev_sectors = lim->max_hw_sectors = + BLK_SAFE_MAX_SECTORS; lim->chunk_sectors = 0; lim->max_write_same_sectors = 0; lim->max_discard_sectors = 0; @@ -127,6 +128,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_hw_sectors = UINT_MAX; lim->max_segment_size = UINT_MAX; lim->max_sectors = UINT_MAX; + lim->max_dev_sectors = UINT_MAX; lim->max_write_same_sectors = UINT_MAX; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -214,8 +216,8 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr) EXPORT_SYMBOL(blk_queue_bounce_limit); /** - * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request - * @limits: the queue limits + * blk_queue_max_hw_sectors - set max sectors for a request for this queue + * @q: the request queue for the device * @max_hw_sectors: max hardware sectors in the usual 512b unit * * Description: @@ -224,13 +226,19 @@ EXPORT_SYMBOL(blk_queue_bounce_limit); * the device driver based upon the capabilities of the I/O * controller. * + * max_dev_sectors is a hard limit imposed by the storage device for + * READ/WRITE requests. It is set by the disk driver. + * * max_sectors is a soft limit imposed by the block layer for * filesystem type requests. This value can be overridden on a * per-device basis in /sys/block//queue/max_sectors_kb. * The soft limit can not exceed max_hw_sectors. **/ -void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors) +void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) { + struct queue_limits *limits = &q->limits; + unsigned int max_sectors; + if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) { max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9); printk(KERN_INFO "%s: set to minimum %d\n", @@ -238,22 +246,9 @@ void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_ } limits->max_hw_sectors = max_hw_sectors; - limits->max_sectors = min_t(unsigned int, max_hw_sectors, - BLK_DEF_MAX_SECTORS); -} -EXPORT_SYMBOL(blk_limits_max_hw_sectors); - -/** - * blk_queue_max_hw_sectors - set max sectors for a request for this queue - * @q: the request queue for the device - * @max_hw_sectors: max hardware sectors in the usual 512b unit - * - * Description: - * See description for blk_limits_max_hw_sectors(). - **/ -void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) -{ - blk_limits_max_hw_sectors(&q->limits, max_hw_sectors); + max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors); + max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS); + limits->max_sectors = max_sectors; } EXPORT_SYMBOL(blk_queue_max_hw_sectors); @@ -527,6 +522,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); + t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors); t->max_write_same_sectors = min(t->max_write_same_sectors, b->max_write_same_sectors); t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 3e44a9da2a13..55c637b9c42b 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -205,6 +205,9 @@ queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) if (ret < 0) return ret; + max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long) + q->limits.max_dev_sectors >> 1); + if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) return -EINVAL; -- cgit v1.2.3