Commit 858c708d authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: move the bi_size update out of __bio_try_merge_page 



The update of bi_size is the only thing in __bio_try_merge_page that
needs a bio.  Move it to the callers, and merge __bio_try_merge_page
and page_is_mergeable into a single bvec_try_merge_page that only takes
the current bvec instead of a full bio.  This will allow reusing this
function for supporting multi-page integrity payload bvecs.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJinyoung Choi <j-young.choi@samsung.com>
Link: https://lore.kernel.org/r/20230724165433.117645-8-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 80232b52

block/bio.c

+20 −37
Original line number Diff line number Diff line
@@ -903,9 +903,8 @@ static inline bool bio_full(struct bio *bio, unsigned len) 
	return false;

}



static inline bool page_is_mergeable(const struct bio_vec *bv,

		struct page *page, unsigned int len, unsigned int off,

		bool *same_page)

static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page,

		unsigned int len, unsigned int off, bool *same_page)

{

	size_t bv_end = bv->bv_offset + bv->bv_len;

	phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;
@@ -919,38 +918,14 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, 
		return false;



	*same_page = ((vec_end_addr & PAGE_MASK) == page_addr);

	if (*same_page)

		return true;

	else if (IS_ENABLED(CONFIG_KMSAN))

	if (!*same_page) {

		if (IS_ENABLED(CONFIG_KMSAN))

			return false;

		if (bv->bv_page + bv_end / PAGE_SIZE != page + off / PAGE_SIZE)

			return false;

	return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE);

	}



/**

 * __bio_try_merge_page - try appending data to an existing bvec.

 * @bio: destination bio

 * @page: start page to add

 * @len: length of the data to add

 * @off: offset of the data relative to @page

 * @same_page: return if the segment has been merged inside the same page

 *

 * Try to add the data at @page + @off to the last bvec of @bio.  This is a

 * useful optimisation for file systems with a block size smaller than the

 * page size.

 *

 * Warn if (@len, @off) crosses pages in case that @same_page is true.

 *

 * Return %true on success or %false on failure.

 */

static bool __bio_try_merge_page(struct bio *bio, struct page *page,

		unsigned int len, unsigned int off, bool *same_page)

{

	struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];



	if (!page_is_mergeable(bv, page, len, off, same_page))

		return false;

	bv->bv_len += len;

	bio->bi_iter.bi_size += len;

	return true;

}
@@ -972,7 +947,7 @@ static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio, 
		return false;

	if (bv->bv_len + len > queue_max_segment_size(q))

		return false;

	return __bio_try_merge_page(bio, page, len, offset, same_page);

	return bvec_try_merge_page(bv, page, len, offset, same_page);

}



/**
@@ -1001,8 +976,11 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio, 
		return 0;



	if (bio->bi_vcnt > 0) {

		if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))

		if (bio_try_merge_hw_seg(q, bio, page, len, offset,

				same_page)) {

			bio->bi_iter.bi_size += len;

			return len;

		}



		if (bio->bi_vcnt >=

		    min(bio->bi_max_vecs, queue_max_segments(q)))
@@ -1123,8 +1101,11 @@ int bio_add_page(struct bio *bio, struct page *page, 
		return 0;



	if (bio->bi_vcnt > 0 &&

	    __bio_try_merge_page(bio, page, len, offset, &same_page))

	    bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],

				page, len, offset, &same_page)) {

		bio->bi_iter.bi_size += len;

		return len;

	}



	if (bio->bi_vcnt >= bio->bi_max_vecs)

		return 0;
@@ -1206,7 +1187,9 @@ static int bio_iov_add_page(struct bio *bio, struct page *page, 
		return -EIO;



	if (bio->bi_vcnt > 0 &&

	    __bio_try_merge_page(bio, page, len, offset, &same_page)) {

	    bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],

				page, len, offset, &same_page)) {

		bio->bi_iter.bi_size += len;

		if (same_page)

			bio_release_page(bio, page);

		return 0;