Don't keep blk_bio_segment_split()'s fast path hand coded in
__blk_queue_split(), extract it into a function. It's inlined perfectly
well.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
block/blk-merge.c | 84 ++++++++++++++++++++++++++---------------------
1 file changed, 46 insertions(+), 38 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 808768f6b174..84b9635b5d57 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -223,29 +223,10 @@ static bool bvec_split_segs(const struct request_queue *q,
return len > 0 || bv->bv_len > max_len;
}
-/**
- * blk_bio_segment_split - split a bio in two bios
- * @q: [in] request queue pointer
- * @bio: [in] bio to be split
- * @bs: [in] bio set to allocate the clone from
- * @segs: [out] number of segments in the bio with the first half of the sectors
- *
- * Clone @bio, update the bi_iter of the clone to represent the first sectors
- * of @bio and update @bio->bi_iter to represent the remaining sectors. The
- * following is guaranteed for the cloned bio:
- * - That it has at most get_max_io_size(@q, @bio) sectors.
- * - That it has at most queue_max_segments(@q) segments.
- *
- * Except for discard requests the cloned bio will point at the bi_io_vec of
- * the original bio. It is the responsibility of the caller to ensure that the
- * original bio is not freed before the cloned bio. The caller is also
- * responsible for ensuring that @bs is only destroyed after processing of the
- * split bio has finished.
- */
-static struct bio *blk_bio_segment_split(struct request_queue *q,
- struct bio *bio,
- struct bio_set *bs,
- unsigned *segs)
+static struct bio *__blk_bio_segment_split(struct request_queue *q,
+ struct bio *bio,
+ struct bio_set *bs,
+ unsigned *segs)
{
struct bio_vec bv, bvprv, *bvprvp = NULL;
struct bvec_iter iter;
@@ -290,6 +271,48 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
return bio_split(bio, sectors, GFP_NOIO, bs);
}
+/**
+ * blk_bio_segment_split - split a bio in two bios
+ * @q: [in] request queue pointer
+ * @bio: [in] bio to be split
+ * @bs: [in] bio set to allocate the clone from
+ * @segs: [out] number of segments in the bio with the first half of the sectors
+ *
+ * Clone @bio, update the bi_iter of the clone to represent the first sectors
+ * of @bio and update @bio->bi_iter to represent the remaining sectors. The
+ * following is guaranteed for the cloned bio:
+ * - That it has at most get_max_io_size(@q, @bio) sectors.
+ * - That it has at most queue_max_segments(@q) segments.
+ *
+ * Except for discard requests the cloned bio will point at the bi_io_vec of
+ * the original bio. It is the responsibility of the caller to ensure that the
+ * original bio is not freed before the cloned bio. The caller is also
+ * responsible for ensuring that @bs is only destroyed after processing of the
+ * split bio has finished.
+ */
+static inline struct bio *blk_bio_segment_split(struct request_queue *q,
+ struct bio *bio,
+ struct bio_set *bs,
+ unsigned *nr_segs)
+{
+ /*
+ * All drivers must accept single-segments bios that are <=
+ * PAGE_SIZE. This is a quick and dirty check that relies on
+ * the fact that bi_io_vec[0] is always valid if a bio has data.
+ * The check might lead to occasional false negatives when bios
+ * are cloned, but compared to the performance impact of cloned
+ * bios themselves the loop below doesn't matter anyway.
+ */
+ if (!q->limits.chunk_sectors && bio->bi_vcnt == 1 &&
+ (bio->bi_io_vec[0].bv_len +
+ bio->bi_io_vec[0].bv_offset) <= PAGE_SIZE) {
+ *nr_segs = 1;
+ return NULL;
+ }
+
+ return __blk_bio_segment_split(q, bio, bs, nr_segs);
+}
+
/**
* __blk_queue_split - split a bio and submit the second half
* @bio: [in, out] bio to be split
@@ -322,21 +345,6 @@ void __blk_queue_split(struct bio **bio, unsigned int *nr_segs)
nr_segs);
break;
default:
- /*
- * All drivers must accept single-segments bios that are <=
- * PAGE_SIZE. This is a quick and dirty check that relies on
- * the fact that bi_io_vec[0] is always valid if a bio has data.
- * The check might lead to occasional false negatives when bios
- * are cloned, but compared to the performance impact of cloned
- * bios themselves the loop below doesn't matter anyway.
- */
- if (!q->limits.chunk_sectors &&
- (*bio)->bi_vcnt == 1 &&
- ((*bio)->bi_io_vec[0].bv_len +
- (*bio)->bi_io_vec[0].bv_offset) <= PAGE_SIZE) {
- *nr_segs = 1;
- break;
- }
split = blk_bio_segment_split(q, *bio, &q->bio_split, nr_segs);
break;
}
--
2.24.0
