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authorMartin K. Petersen <martin.petersen@oracle.com>2015-11-13 16:46:48 -0500
committerMartin K. Petersen <martin.petersen@oracle.com>2015-11-25 21:38:58 -0500
commitca369d51b3e1649be4a72addd6d6a168cfb3f537 (patch)
tree38f0d07a92f6939da923b0ef8948ea6e8b44b2a6 /block/blk-settings.c
parentf7f9f26b139e53d798ea76465223a5f237d90fd3 (diff)
downloadlinux-linaro-stable-ca369d51b3e1649be4a72addd6d6a168cfb3f537.tar.gz
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 <martin.petersen@oracle.com> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93581 Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: sweeneygj@gmx.com Tested-by: Arzeets <anatol.pomozov@gmail.com> Tested-by: David Eisner <david.eisner@oriel.oxon.org> Tested-by: Mario Kicherer <dev@kicherer.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r--block/blk-settings.c36
1 files changed, 16 insertions, 20 deletions
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/<device>/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);