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-rw-r--r--block/blk-merge.c55
1 files changed, 41 insertions, 14 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 3eec75a9e91d..2642e5fc8b69 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -94,9 +94,31 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
bool do_split = true;
struct bio *new = NULL;
const unsigned max_sectors = get_max_io_size(q, bio);
+ unsigned bvecs = 0;
bio_for_each_segment(bv, bio, iter) {
/*
+ * With arbitrary bio size, the incoming bio may be very
+ * big. We have to split the bio into small bios so that
+ * each holds at most BIO_MAX_PAGES bvecs because
+ * bio_clone() can fail to allocate big bvecs.
+ *
+ * It should have been better to apply the limit per
+ * request queue in which bio_clone() is involved,
+ * instead of globally. The biggest blocker is the
+ * bio_clone() in bio bounce.
+ *
+ * If bio is splitted by this reason, we should have
+ * allowed to continue bios merging, but don't do
+ * that now for making the change simple.
+ *
+ * TODO: deal with bio bounce's bio_clone() gracefully
+ * and convert the global limit into per-queue limit.
+ */
+ if (bvecs++ >= BIO_MAX_PAGES)
+ goto split;
+
+ /*
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
*/
@@ -172,12 +194,18 @@ void blk_queue_split(struct request_queue *q, struct bio **bio,
struct bio *split, *res;
unsigned nsegs;
- if (bio_op(*bio) == REQ_OP_DISCARD)
+ switch (bio_op(*bio)) {
+ case REQ_OP_DISCARD:
+ case REQ_OP_SECURE_ERASE:
split = blk_bio_discard_split(q, *bio, bs, &nsegs);
- else if (bio_op(*bio) == REQ_OP_WRITE_SAME)
+ break;
+ case REQ_OP_WRITE_SAME:
split = blk_bio_write_same_split(q, *bio, bs, &nsegs);
- else
+ break;
+ default:
split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs);
+ break;
+ }
/* physical segments can be figured out during splitting */
res = split ? split : *bio;
@@ -213,7 +241,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
* This should probably be returning 0, but blk_add_request_payload()
* (Christoph!!!!)
*/
- if (bio_op(bio) == REQ_OP_DISCARD)
+ if (bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_SECURE_ERASE)
return 1;
if (bio_op(bio) == REQ_OP_WRITE_SAME)
@@ -385,7 +413,9 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio,
nsegs = 0;
cluster = blk_queue_cluster(q);
- if (bio_op(bio) == REQ_OP_DISCARD) {
+ switch (bio_op(bio)) {
+ case REQ_OP_DISCARD:
+ case REQ_OP_SECURE_ERASE:
/*
* This is a hack - drivers should be neither modifying the
* biovec, nor relying on bi_vcnt - but because of
@@ -393,19 +423,16 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio,
* a payload we need to set up here (thank you Christoph) and
* bi_vcnt is really the only way of telling if we need to.
*/
-
- if (bio->bi_vcnt)
- goto single_segment;
-
- return 0;
- }
-
- if (bio_op(bio) == REQ_OP_WRITE_SAME) {
-single_segment:
+ if (!bio->bi_vcnt)
+ return 0;
+ /* Fall through */
+ case REQ_OP_WRITE_SAME:
*sg = sglist;
bvec = bio_iovec(bio);
sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset);
return 1;
+ default:
+ break;
}
for_each_bio(bio)