block: Check for gaps on front and back merges
We are checking for gaps to previous bio_vec, which can
only detect back merges gaps. Moreover, at the point where
we check for a gap, we don't know if we will attempt a back
or a front merge. Thus, check for gap to prev in a back merge
attempt and check for a gap to next in a front merge attempt.
Signed-off-by: Jens Axboe <axboe@fb.com>
[sagig: Minor rename change]
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a622f27..2ff94de 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1368,6 +1368,26 @@
((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
}
+static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
+ struct bio *next)
+{
+ if (!bio_has_data(prev))
+ return false;
+
+ return bvec_gap_to_prev(q, &prev->bi_io_vec[prev->bi_vcnt - 1],
+ next->bi_io_vec[0].bv_offset);
+}
+
+static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
+{
+ return bio_will_gap(req->q, req->biotail, bio);
+}
+
+static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
+{
+ return bio_will_gap(req->q, bio, req->bio);
+}
+
struct work_struct;
int kblockd_schedule_work(struct work_struct *work);
int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);