[RFC PATCH 10/28] block: Create generic vec_split_segs() from bvec_split_segs()

Logan Gunthorpe
2019-06-20T16:12:22Z

bvec_split_segs() only requires the address and length of the
vector. In order to generalize it to work with dma_vecs, we just
take the address and length directly instead of the bio_vec.

The function is renamed to vec_split_segs() and a helper is added
to avoid having to adjust the existing callsites.

Note: the new bvec_split_segs() helper will be removed in a subsequent
patch.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
block/blk-merge.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 17713d7d98d5..3581c7ac3c1b 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -158,13 +158,13 @@ static unsigned get_max_segment_size(struct request_queue *q,
}

/*
- * Split the bvec @bv into segments, and update all kinds of
- * variables.
+ * Split the an address/offset and length into segments, and
+ * update all kinds of variables.
*/
-static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
- unsigned *nsegs, unsigned *sectors, unsigned max_segs)
+static bool vec_split_segs(struct request_queue *q, unsigned offset,
+ unsigned len, unsigned *nsegs, unsigned *sectors,
+ unsigned max_segs)
{
- unsigned len = bv->bv_len;
unsigned total_len = 0;
unsigned new_nsegs = 0, seg_size = 0;

@@ -173,14 +173,14 @@ static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
* current bvec has to be splitted as multiple segments.
*/
while (len && new_nsegs + *nsegs < max_segs) {
- seg_size = get_max_segment_size(q, bv->bv_offset + total_len);
+ seg_size = get_max_segment_size(q, offset + total_len);
seg_size = min(seg_size, len);

new_nsegs++;
total_len += seg_size;
len -= seg_size;

- if ((bv->bv_offset + total_len) & queue_virt_boundary(q))
+ if ((offset + total_len) & queue_virt_boundary(q))
break;
}

@@ -194,6 +194,13 @@ static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
return !!len;
}

+static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
+ unsigned *nsegs, unsigned *sectors, unsigned max_segs)
+{
+ return vec_split_segs(q, bv->bv_offset, bv->bv_len, nsegs,
+ sectors, max_segs);
+}
+
static struct bio *blk_bio_segment_split(struct request_queue *q,
struct bio *bio,
struct bio_set *bs,
--
2.20.1