block/scsi: Provide a limit on the number of integrity segments
Some controllers have a hardware limit on the number of protection
information scatter-gather list segments they can handle.
Introduce a max_integrity_segments limit in the block layer and provide
a new scsi_host_template setting that allows HBA drivers to provide a
value suitable for the hardware.
Add support for honoring the integrity segment limit when merging both
bios and requests.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index edce1ef..885cbb5 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -32,24 +32,37 @@
/**
* blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
- * @rq: request with integrity metadata attached
+ * @q: request queue
+ * @bio: bio with integrity metadata attached
*
* Description: Returns the number of elements required in a
- * scatterlist corresponding to the integrity metadata in a request.
+ * scatterlist corresponding to the integrity metadata in a bio.
*/
-int blk_rq_count_integrity_sg(struct request *rq)
+int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
{
- struct bio_vec *iv, *ivprv;
- struct req_iterator iter;
- unsigned int segments;
+ struct bio_vec *iv, *ivprv = NULL;
+ unsigned int segments = 0;
+ unsigned int seg_size = 0;
+ unsigned int i = 0;
- ivprv = NULL;
- segments = 0;
+ bio_for_each_integrity_vec(iv, bio, i) {
- rq_for_each_integrity_segment(iv, rq, iter) {
+ if (ivprv) {
+ if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
+ goto new_segment;
- if (!ivprv || !BIOVEC_PHYS_MERGEABLE(ivprv, iv))
+ if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
+ goto new_segment;
+
+ if (seg_size + iv->bv_len > queue_max_segment_size(q))
+ goto new_segment;
+
+ seg_size += iv->bv_len;
+ } else {
+new_segment:
segments++;
+ seg_size = iv->bv_len;
+ }
ivprv = iv;
}
@@ -60,30 +73,34 @@
/**
* blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
- * @rq: request with integrity metadata attached
+ * @q: request queue
+ * @bio: bio with integrity metadata attached
* @sglist: target scatterlist
*
* Description: Map the integrity vectors in request into a
* scatterlist. The scatterlist must be big enough to hold all
* elements. I.e. sized using blk_rq_count_integrity_sg().
*/
-int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist)
+int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
+ struct scatterlist *sglist)
{
- struct bio_vec *iv, *ivprv;
- struct req_iterator iter;
- struct scatterlist *sg;
- unsigned int segments;
+ struct bio_vec *iv, *ivprv = NULL;
+ struct scatterlist *sg = NULL;
+ unsigned int segments = 0;
+ unsigned int i = 0;
- ivprv = NULL;
- sg = NULL;
- segments = 0;
-
- rq_for_each_integrity_segment(iv, rq, iter) {
+ bio_for_each_integrity_vec(iv, bio, i) {
if (ivprv) {
if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
goto new_segment;
+ if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
+ goto new_segment;
+
+ if (sg->length + iv->bv_len > queue_max_segment_size(q))
+ goto new_segment;
+
sg->length += iv->bv_len;
} else {
new_segment:
@@ -162,6 +179,40 @@
}
EXPORT_SYMBOL(blk_integrity_compare);
+int blk_integrity_merge_rq(struct request_queue *q, struct request *req,
+ struct request *next)
+{
+ if (blk_integrity_rq(req) != blk_integrity_rq(next))
+ return -1;
+
+ if (req->nr_integrity_segments + next->nr_integrity_segments >
+ q->limits.max_integrity_segments)
+ return -1;
+
+ return 0;
+}
+EXPORT_SYMBOL(blk_integrity_merge_rq);
+
+int blk_integrity_merge_bio(struct request_queue *q, struct request *req,
+ struct bio *bio)
+{
+ int nr_integrity_segs;
+ struct bio *next = bio->bi_next;
+
+ bio->bi_next = NULL;
+ nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
+ bio->bi_next = next;
+
+ if (req->nr_integrity_segments + nr_integrity_segs >
+ q->limits.max_integrity_segments)
+ return -1;
+
+ req->nr_integrity_segments += nr_integrity_segs;
+
+ return 0;
+}
+EXPORT_SYMBOL(blk_integrity_merge_bio);
+
struct integrity_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct blk_integrity *, char *);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 3b0cd42..6a72546 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -205,12 +205,11 @@
{
int nr_phys_segs = bio_phys_segments(q, bio);
- if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) {
- req->cmd_flags |= REQ_NOMERGE;
- if (req == q->last_merge)
- q->last_merge = NULL;
- return 0;
- }
+ if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q))
+ goto no_merge;
+
+ if (bio_integrity(bio) && blk_integrity_merge_bio(q, req, bio))
+ goto no_merge;
/*
* This will form the start of a new hw segment. Bump both
@@ -218,6 +217,12 @@
*/
req->nr_phys_segments += nr_phys_segs;
return 1;
+
+no_merge:
+ req->cmd_flags |= REQ_NOMERGE;
+ if (req == q->last_merge)
+ q->last_merge = NULL;
+ return 0;
}
int ll_back_merge_fn(struct request_queue *q, struct request *req,
@@ -301,6 +306,9 @@
if (total_phys_segments > queue_max_segments(q))
return 0;
+ if (blk_integrity_rq(req) && blk_integrity_merge_rq(q, req, next))
+ return 0;
+
/* Merge is OK... */
req->nr_phys_segments = total_phys_segments;
return 1;
@@ -372,9 +380,6 @@
|| next->special)
return 0;
- if (blk_integrity_rq(req) != blk_integrity_rq(next))
- return 0;
-
/*
* If we are allowed to merge, then append bio list
* from next to rq and release next. merge_requests_fn
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 8d592b5..f8f2ddf 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -111,6 +111,7 @@
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->max_segment_size = BLK_MAX_SEGMENT_SIZE;
lim->max_sectors = BLK_DEF_MAX_SECTORS;
@@ -509,6 +510,8 @@
b->seg_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,
+ b->max_integrity_segments);
t->max_segment_size = min_not_zero(t->max_segment_size,
b->max_segment_size);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 001ab18..b014f77 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -112,6 +112,11 @@
return queue_var_show(queue_max_segments(q), (page));
}
+static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(q->limits.max_integrity_segments, (page));
+}
+
static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
{
if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
@@ -288,6 +293,11 @@
.show = queue_max_segments_show,
};
+static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
+ .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
+ .show = queue_max_integrity_segments_show,
+};
+
static struct queue_sysfs_entry queue_max_segment_size_entry = {
.attr = {.name = "max_segment_size", .mode = S_IRUGO },
.show = queue_max_segment_size_show,
@@ -375,6 +385,7 @@
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
&queue_max_segments_entry.attr,
+ &queue_max_integrity_segments_entry.attr,
&queue_max_segment_size_entry.attr,
&queue_iosched_entry.attr,
&queue_hw_sector_size_entry.attr,
diff --git a/block/blk.h b/block/blk.h
index 6e7dc87..6738831 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -132,14 +132,6 @@
return q->nr_congestion_off;
}
-#if defined(CONFIG_BLK_DEV_INTEGRITY)
-
-#define rq_for_each_integrity_segment(bvl, _rq, _iter) \
- __rq_for_each_bio(_iter.bio, _rq) \
- bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
-
-#endif /* BLK_DEV_INTEGRITY */
-
static inline int blk_cpu_to_group(int cpu)
{
#ifdef CONFIG_SCHED_MC