block: Replace SG_GAPS with new queue limits mask

The SG_GAPS queue flag caused checks for bio vector alignment against
PAGE_SIZE, but the device may have different constraints. This patch
adds a queue limits so a driver with such constraints can set to allow
requests that would have been unnecessarily split. The new gaps check
takes the request_queue as a parameter to simplify the logic around
invoking this function.

This new limit makes the queue flag redundant, so removing it and
all usage. Device-mappers will inherit the correct settings through
blk_stack_limits().

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Keith Busch
2015-08-19 14:24:05 -07:00
committed by Jens Axboe
parent d2be537c3b
commit 03100aada9
7 changed files with 43 additions and 42 deletions

View File

@@ -89,6 +89,7 @@ void blk_set_default_limits(struct queue_limits *lim)
lim->max_segments = BLK_MAX_SEGMENTS;
lim->max_integrity_segments = 0;
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->chunk_sectors = 0;
@@ -532,6 +533,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
b->seg_boundary_mask);
t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
b->virt_boundary_mask);
t->max_segments = min_not_zero(t->max_segments, b->max_segments);
t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
@@ -771,6 +774,17 @@ void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
}
EXPORT_SYMBOL(blk_queue_segment_boundary);
/**
* blk_queue_virt_boundary - set boundary rules for bio merging
* @q: the request queue for the device
* @mask: the memory boundary mask
**/
void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
{
q->limits.virt_boundary_mask = mask;
}
EXPORT_SYMBOL(blk_queue_virt_boundary);
/**
* blk_queue_dma_alignment - set dma length and memory alignment
* @q: the request queue for the device