Premapped buffers don't require a generic bio_vec since these have already been dma mapped. Repurpose the bi_io_vec space to strore dmabuf maps as they are mutually exclusive.
Suggested-by: Keith Busch kbusch@kernel.org Signed-off-by: Pavel Begunkov asml.silence@gmail.com --- block/bio.c | 25 ++++++++++++++++++++++++- block/blk-merge.c | 14 ++++++++++++++ block/blk.h | 3 ++- block/fops.c | 2 ++ include/linux/bio.h | 19 ++++++++++++++++--- include/linux/blk_types.h | 8 +++++++- 6 files changed, 65 insertions(+), 6 deletions(-)
diff --git a/block/bio.c b/block/bio.c index 0734b50d4992..bdc91777c288 100644 --- a/block/bio.c +++ b/block/bio.c @@ -851,7 +851,13 @@ static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp) bio->bi_write_hint = bio_src->bi_write_hint; bio->bi_write_stream = bio_src->bi_write_stream; bio->bi_iter = bio_src->bi_iter; - bio->bi_io_vec = bio_src->bi_io_vec; + + if (!bio_flagged(bio_src, BIO_DMABUF_MAP)) { + bio->bi_io_vec = bio_src->bi_io_vec; + } else { + bio->dmabuf_map = bio_src->dmabuf_map; + bio_set_flag(bio, BIO_DMABUF_MAP); + }
if (bio->bi_bdev) { if (bio->bi_bdev == bio_src->bi_bdev && @@ -1183,6 +1189,18 @@ void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter) bio_set_flag(bio, BIO_CLONED); }
+void bio_dmabuf_map_set(struct bio *bio, struct iov_iter *iter) +{ + WARN_ON_ONCE(bio->bi_max_vecs); + + bio->dmabuf_map = iter->dmabuf_map; + bio->bi_vcnt = 0; + bio->bi_iter.bi_bvec_done = iter->iov_offset; + bio->bi_iter.bi_size = iov_iter_count(iter); + bio->bi_opf |= REQ_NOMERGE; + bio_set_flag(bio, BIO_DMABUF_MAP); +} + /* * Aligns the bio size to the len_align_mask, releasing excessive bio vecs that * __bio_iov_iter_get_pages may have inserted, and reverts the trimmed length @@ -1252,6 +1270,11 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, iov_iter_advance(iter, bio->bi_iter.bi_size); return 0; } + if (iov_iter_is_dmabuf_map(iter)) { + bio_dmabuf_map_set(bio, iter); + iov_iter_advance(iter, bio->bi_iter.bi_size); + return 0; + }
if (iov_iter_extract_will_pin(iter)) bio_set_flag(bio, BIO_PAGE_PINNED); diff --git a/block/blk-merge.c b/block/blk-merge.c index fcf09325b22e..fc2c0c428001 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -348,6 +348,19 @@ int bio_split_io_at(struct bio *bio, const struct queue_limits *lim, len_align_mask |= (bc->bc_key->crypto_cfg.data_unit_size - 1); }
+ if (bio_flagged(bio, BIO_DMABUF_MAP)) { + nsegs = 1; + + if ((bio->bi_iter.bi_bvec_done & lim->dma_alignment) || + (bio->bi_iter.bi_size & len_align_mask)) + return -EINVAL; + if (bio->bi_iter.bi_size > max_bytes) { + bytes = max_bytes; + goto split; + } + goto out; + } + bio_for_each_bvec(bv, bio, iter) { if (bv.bv_offset & start_align_mask || bv.bv_len & len_align_mask) @@ -378,6 +391,7 @@ int bio_split_io_at(struct bio *bio, const struct queue_limits *lim, bvprvp = &bvprv; }
+out: *segs = nsegs; bio->bi_bvec_gap_bit = ffs(gaps); return 0; diff --git a/block/blk.h b/block/blk.h index b998a7761faf..b4b09abebce8 100644 --- a/block/blk.h +++ b/block/blk.h @@ -424,7 +424,8 @@ static inline struct bio *__bio_split_to_limits(struct bio *bio, switch (bio_op(bio)) { case REQ_OP_READ: case REQ_OP_WRITE: - if (bio_may_need_split(bio, lim)) + if (bio_may_need_split(bio, lim) || + bio_flagged(bio, BIO_DMABUF_MAP)) return bio_split_rw(bio, lim, nr_segs); *nr_segs = 1; return bio; diff --git a/block/fops.c b/block/fops.c index bb6642b45937..713a3ba3f457 100644 --- a/block/fops.c +++ b/block/fops.c @@ -349,6 +349,8 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, * bio_iov_iter_get_pages() and set the bvec directly. */ bio_iov_bvec_set(bio, iter); + } else if (iov_iter_is_dmabuf_map(iter)) { + bio_dmabuf_map_set(bio, iter); } else { ret = blkdev_iov_iter_get_pages(bio, iter, bdev); if (unlikely(ret)) diff --git a/include/linux/bio.h b/include/linux/bio.h index 97d747320b35..0c43fa6b0900 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -108,16 +108,26 @@ static inline bool bio_next_segment(const struct bio *bio, #define bio_for_each_segment_all(bvl, bio, iter) \ for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
+static inline void bio_advance_iter_dmabuf_map(struct bvec_iter *iter, + unsigned int bytes) +{ + iter->bi_bvec_done += bytes; + iter->bi_size -= bytes; +} + static inline void bio_advance_iter(const struct bio *bio, struct bvec_iter *iter, unsigned int bytes) { iter->bi_sector += bytes >> 9;
- if (bio_no_advance_iter(bio)) + if (bio_no_advance_iter(bio)) { iter->bi_size -= bytes; - else + } else if (bio_flagged(bio, BIO_DMABUF_MAP)) { + bio_advance_iter_dmabuf_map(iter, bytes); + } else { bvec_iter_advance(bio->bi_io_vec, iter, bytes); /* TODO: It is reasonable to complete bio with error here. */ + } }
/* @bytes should be less or equal to bvec[i->bi_idx].bv_len */ @@ -129,6 +139,8 @@ static inline void bio_advance_iter_single(const struct bio *bio,
if (bio_no_advance_iter(bio)) iter->bi_size -= bytes; + else if (bio_flagged(bio, BIO_DMABUF_MAP)) + bio_advance_iter_dmabuf_map(iter, bytes); else bvec_iter_advance_single(bio->bi_io_vec, iter, bytes); } @@ -391,7 +403,7 @@ static inline void bio_wouldblock_error(struct bio *bio) */ static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs) { - if (iov_iter_is_bvec(iter)) + if (iov_iter_is_bvec(iter) || iov_iter_is_dmabuf_map(iter)) return 0; return iov_iter_npages(iter, max_segs); } @@ -471,6 +483,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, unsigned len_align_mask);
void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter); +void bio_dmabuf_map_set(struct bio *bio, struct iov_iter *iter); void __bio_release_pages(struct bio *bio, bool mark_dirty); extern void bio_set_pages_dirty(struct bio *bio); extern void bio_check_pages_dirty(struct bio *bio); diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 8808ee76e73c..d5ad085b701d 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -233,7 +233,12 @@ struct bio { atomic_t __bi_remaining;
/* The actual vec list, preserved by bio_reset() */ - struct bio_vec *bi_io_vec; + union { + struct bio_vec *bi_io_vec; + /* Driver specific dma map, present only with BIO_DMABUF_MAP */ + struct io_dmabuf_map *dmabuf_map; + }; + struct bvec_iter bi_iter;
union { @@ -322,6 +327,7 @@ enum { BIO_REMAPPED, BIO_ZONE_WRITE_PLUGGING, /* bio handled through zone write plugging */ BIO_EMULATES_ZONE_APPEND, /* bio emulates a zone append operation */ + BIO_DMABUF_MAP, /* Using premmaped dma buffers */ BIO_FLAG_LAST };