• bio->bi_io_vec = bio_src->bi_io_vec;

• if (op_is_dmabuf(bio->bi_opf)) {

• bio->bi_dmabuf_map = bio_src->bi_dmabuf_map;
  

• } else {

• bio->bi_io_vec = bio_src->bi_io_vec;
  

• }

No need for the braces. But given that these are the fields why even bother doing both sides and not rely on the union?

+void bio_dmabuf_map_set(struct bio *bio, struct iov_iter *iter) +{

• WARN_ON_ONCE(bio->bi_max_vecs);
• bio->bi_dmabuf_map = iter->dmabuf_map;
• bio->bi_vcnt = 0;
• bio->bi_iter.bi_offset = iter->iov_offset;
• bio->bi_iter.bi_size = iov_iter_count(iter);
• bio->bi_opf |= REQ_NOMERGE | REQ_DMABUF;

This seems to be largely copied from bio_iov_bvec_set, but misses the REQ_CLONE there that we should probably set as well to indicate that the data descriptor is not owned (although not setting it is not really a bug).

What about merging these two into a single and easier to use interface like this:

diff --git a/block/bio.c b/block/bio.c index cc2bb9183c1a..25393bdd119d 100644 --- a/block/bio.c +++ b/block/bio.c @@ -860,12 +860,9 @@ 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; - - if (op_is_dmabuf(bio->bi_opf)) { - bio->bi_dmabuf_map = bio_src->bi_dmabuf_map; - } else { - bio->bi_io_vec = bio_src->bi_io_vec; - } + static_assert(offsetof(struct bio, bi_io_vec) == + offsetof(struct bio, bi_dmabuf_map)); + bio->bi_io_vec = bio_src->bi_io_vec;

if (bio->bi_bdev) { if (bio->bi_bdev == bio_src->bi_bdev && @@ -1186,26 +1183,21 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty) } EXPORT_SYMBOL_GPL(__bio_release_pages);

-void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter) +bool bio_iov_iter_set(struct bio *bio, const struct iov_iter *iter) { WARN_ON_ONCE(bio->bi_max_vecs);

+ if (!iov_iter_is_bvec(iter) && !iov_iter_is_dmabuf_map(iter)) + return false; + bio->bi_io_vec = (struct bio_vec *)iter->bvec; bio->bi_iter.bi_idx = 0; bio->bi_iter.bi_offset = iter->iov_offset; bio->bi_iter.bi_size = iov_iter_count(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->bi_dmabuf_map = iter->dmabuf_map; - bio->bi_vcnt = 0; - bio->bi_iter.bi_offset = iter->iov_offset; - bio->bi_iter.bi_size = iov_iter_count(iter); - bio->bi_opf |= REQ_NOMERGE | REQ_DMABUF; + if (iov_iter_is_dmabuf_map(iter)) + bio->bi_opf |= REQ_NOMERGE | REQ_DMABUF; + return true; }

/* @@ -1265,13 +1257,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) return -EIO;

- if (iov_iter_is_bvec(iter)) { - bio_iov_bvec_set(bio, 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); + if (bio_iov_iter_set(bio, iter)) { iov_iter_advance(iter, bio->bi_iter.bi_size); return 0; } diff --git a/block/blk-map.c b/block/blk-map.c index d1d6bbe0ecf1..34816e6e64de 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -473,7 +473,7 @@ static int blk_rq_map_user_bvec(struct request *rq, const struct iov_iter *iter) bio = blk_rq_map_bio_alloc(rq, 0, GFP_KERNEL); if (!bio) return -ENOMEM; - bio_iov_bvec_set(bio, iter); + bio_iov_iter_set(bio, iter);

ret = blk_rq_append_bio(rq, bio); if (ret) diff --git a/block/fops.c b/block/fops.c index d83cdbab65a6..97fb124a19b2 100644 --- a/block/fops.c +++ b/block/fops.c @@ -340,17 +340,12 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, bio->bi_end_io = blkdev_bio_end_io_async; bio->bi_ioprio = iocb->ki_ioprio;

- if (iov_iter_is_bvec(iter)) { - /* - * Users don't rely on the iterator being in any particular - * state for async I/O returning -EIOCBQUEUED, hence we can - * avoid expensive iov_iter_advance(). Bypass - * 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 { + /* + * Users don't rely on the iterator being in any particular state for + * async I/O returning -EIOCBQUEUED, hence we can avoid the expensive + * iov_iter_advance() if we could set the bvec/dmabuf directly. + */ + if (!bio_iov_iter_set(bio, iter)) { ret = blkdev_iov_iter_get_pages(bio, iter, bdev); if (unlikely(ret)) goto out_bio_put; diff --git a/include/linux/bio.h b/include/linux/bio.h index c053e9444514..1eff02a843ef 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -484,8 +484,7 @@ int bdev_rw_virt(struct block_device *bdev, sector_t sector, void *data, 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); +bool bio_iov_iter_set(struct bio *bio, const 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);