ANDROID: block: Support submitting passthrough requests with small segments

If the segment size is smaller than the page size there may be multiple
segments per bvec even if a bvec only contains a single page. Hence this
patch.

Bug: 308663717
Bug: 319125789
Change-Id: I81516bf6da8ce3e4e60651ab2bd379080e7d3482
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Juan Yescas <jyescas@google.com>
This commit is contained in:
Bart Van Assche 2023-06-12 13:33:11 -07:00 committed by Juan Yescas
parent c5b8696597
commit 879eff2954
2 changed files with 19 additions and 1 deletions

View File

@ -531,7 +531,7 @@ int blk_rq_append_bio(struct request *rq, struct bio *bio)
unsigned int nr_segs = 0;
bio_for_each_bvec(bv, bio, iter)
nr_segs++;
nr_segs += blk_segments(&rq->q->limits, bv.bv_len);
if (!rq->bio) {
blk_rq_bio_prep(rq, bio, nr_segs);

View File

@ -91,6 +91,24 @@ struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,
gfp_t gfp_mask);
void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs);
/* Number of DMA segments required to transfer @bytes data. */
static inline unsigned int blk_segments(const struct queue_limits *limits,
unsigned int bytes)
{
if (!blk_queue_sub_page_limits(limits))
return 1;
{
const unsigned int mss = limits->max_segment_size;
if (bytes <= mss)
return 1;
if (is_power_of_2(mss))
return round_up(bytes, mss) >> ilog2(mss);
return (bytes + mss - 1) / mss;
}
}
static inline bool biovec_phys_mergeable(struct request_queue *q,
struct bio_vec *vec1, struct bio_vec *vec2)
{