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>
diff --git a/block/bio.c b/block/bio.c
index 425d6d4..b1f198f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -742,8 +742,7 @@
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
*/
- if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
- bvec_gap_to_prev(prev, offset))
+ if (bvec_gap_to_prev(q, prev, offset))
return 0;
}
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 0027def..0e0d9fd 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -82,8 +82,7 @@
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
*/
- if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
- prev && bvec_gap_to_prev(&bvprv, bv.bv_offset))
+ if (prev && bvec_gap_to_prev(q, &bvprv, bv.bv_offset))
goto split;
if (prev && blk_queue_cluster(q)) {
@@ -484,12 +483,12 @@
return !q->mq_ops && req->special;
}
-static int req_gap_to_prev(struct request *req, struct request *next)
+static int req_gap_to_prev(struct request *req, struct bio *next)
{
struct bio *prev = req->biotail;
- return bvec_gap_to_prev(&prev->bi_io_vec[prev->bi_vcnt - 1],
- next->bio->bi_io_vec[0].bv_offset);
+ return bvec_gap_to_prev(req->q, &prev->bi_io_vec[prev->bi_vcnt - 1],
+ next->bi_io_vec[1].bv_offset);
}
static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
@@ -506,8 +505,7 @@
if (req_no_special_merge(req) || req_no_special_merge(next))
return 0;
- if (test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags) &&
- req_gap_to_prev(req, next))
+ if (req_gap_to_prev(req, next->bio))
return 0;
/*
@@ -692,8 +690,6 @@
bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
{
- struct request_queue *q = rq->q;
-
if (!rq_mergeable(rq) || !bio_mergeable(bio))
return false;
@@ -718,13 +714,8 @@
return false;
/* Only check gaps if the bio carries data */
- if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) && bio_has_data(bio)) {
- struct bio_vec *bprev;
-
- bprev = &rq->biotail->bi_io_vec[rq->biotail->bi_vcnt - 1];
- if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset))
- return false;
- }
+ if (bio_has_data(bio) && req_gap_to_prev(rq, bio))
+ return false;
return true;
}
diff --git a/block/blk-settings.c b/block/blk-settings.c
index d27b4e2..f96c721 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -89,6 +89,7 @@
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 @@
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,
@@ -772,6 +775,17 @@
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
* @mask: alignment mask