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authorMartin K. Petersen <martin.petersen@oracle.com>2010-09-10 20:50:10 +0200
committerJens Axboe <axboe@carl.home.kernel.dk>2010-09-10 20:50:10 +0200
commit13f05c8d8e98bbdce89158bfdb2e380940695a88 (patch)
tree055215e7e2b1bdc684ead64daa61b30b35eaa3c5 /block/blk-integrity.c
parentc8bf1336824ebd698d37b71763e1c43190f2229a (diff)
downloadkernel-13f05c8d8e98bbdce89158bfdb2e380940695a88.tar.gz
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>
Diffstat (limited to 'block/blk-integrity.c')
-rw-r--r--block/blk-integrity.c93
1 files changed, 72 insertions, 21 deletions
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index edce1ef7933d..885cbb59967e 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -32,24 +32,37 @@ static struct kmem_cache *integrity_cachep;
/**
* 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 (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
+ goto new_segment;
+
+ if (seg_size + iv->bv_len > queue_max_segment_size(q))
+ goto new_segment;
- if (!ivprv || !BIOVEC_PHYS_MERGEABLE(ivprv, iv))
+ seg_size += iv->bv_len;
+ } else {
+new_segment:
segments++;
+ seg_size = iv->bv_len;
+ }
ivprv = iv;
}
@@ -60,30 +73,34 @@ EXPORT_SYMBOL(blk_rq_count_integrity_sg);
/**
* 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 @@ int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
}
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 *);