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anolis: virtio-blk: add blk_rq_map_sg_bidirectional helper 

ANBZ: #12584

If a request is bidirectional, we should divide bios into different
sglist, according to its IO direction.

Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Link: https://gitee.com/anolis/cloud-kernel/pulls/4272
This commit is contained in:
Ferry Meng 2024-07-22 16:42:42 +08:00
parent 45a746d87c
commit fb9c8a40b3
2 changed files with 73 additions and 0 deletions
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69
block/blk-merge.c
View File

@ -551,6 +551,75 @@ int __blk_rq_map_sg(struct request_queue *q, struct request *rq,
}
EXPORT_SYMBOL(__blk_rq_map_sg);
static int __blk_bios_map_sg_bidir(struct request_queue *q, struct bio *bio,
struct scatterlist *sglist[], struct scatterlist **sg[])
{
struct bio_vec bvec, bvprv = { NULL };
struct bvec_iter iter;
int nsegs = 0;
bool new_bio = false, write = false, prev_write = false;
/* we have ensure that a bidir req only have two bio in the list,
* what we do here is to map the two bio to two scatterlist.
*/
for_each_bio(bio) {
write = op_is_write(bio_op(bio));
bio_for_each_bvec(bvec, bio, iter) {
/*
* Only try to merge bvecs from two bios given we
* have done bio internal merge when adding pages
* to bio.
* For first time enter this loop, 'new_bio' is
* false, ignore prev_write and write until next
* loop.
*/
if (new_bio && prev_write == write &&
__blk_segment_map_sg_merge(q, &bvec, &bvprv, sg[prev_write]))
goto next_bvec;
if (bvec.bv_offset + bvec.bv_len <= PAGE_SIZE)
nsegs += __blk_bvec_map_sg(bvec, sglist[write], sg[write]);
else
nsegs += blk_bvec_map_sg(q, &bvec, sglist[write], sg[write]);
next_bvec:
new_bio = false;
}
if (likely(bio->bi_iter.bi_size)) {
bvprv = bvec;
new_bio = true;
prev_write = write;
}
}
return nsegs;
}
int blk_rq_map_sg_bidir(struct request_queue *q, struct request *rq,
struct scatterlist *sglist_write, struct scatterlist *sglist_read)
{
int nsegs = 0;
struct scatterlist *sglist[2] = {sglist_read, sglist_write};
struct scatterlist *last_sg_write = NULL, *last_sg_read = NULL;
struct scatterlist **sglist_last[2] = {&last_sg_write, &last_sg_read};
if (rq->bio)
nsegs = __blk_bios_map_sg_bidir(q, rq->bio, sglist, sglist_last);
if (last_sg_write)
sg_mark_end(last_sg_write);
if (last_sg_read)
sg_mark_end(last_sg_read);
/*
* Something must have been wrong if the figured number of
* segment is bigger than number of req's physical segments
*/
WARN_ON(nsegs > blk_rq_nr_phys_segments(rq));
return nsegs;
}
EXPORT_SYMBOL(blk_rq_map_sg_bidir);
static inline unsigned int blk_rq_get_max_segments(struct request *rq)
{
if (req_op(rq) == REQ_OP_DISCARD)

4
include/linux/blkdev.h
View File

@ -1269,6 +1269,10 @@ static inline int blk_rq_map_sg(struct request_queue *q, struct request *rq,
return __blk_rq_map_sg(q, rq, sglist, &last_sg);
}
int blk_rq_map_sg_bidir(struct request_queue *q, struct request *rq,
struct scatterlist *sglist_write, struct scatterlist *sglist_read);
extern void blk_dump_rq_flags(struct request *, char *);
bool __must_check blk_get_queue(struct request_queue *);