Commit 640d1930 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

block: Add bio_for_each_folio_all() 



Allow callers to iterate over each folio instead of each page.  The
bio need not have been constructed using folios originally.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarJens Axboe <axboe@kernel.dk>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 85f5a74c

Documentation/core-api/kernel-api.rst

+1 −0
Original line number Diff line number Diff line
@@ -279,6 +279,7 @@ Accounting Framework 
Block Devices

=============



.. kernel-doc:: include/linux/bio.h

.. kernel-doc:: block/blk-core.c

   :export:

include/linux/bio.h

+52 −1
Original line number Diff line number Diff line
@@ -166,7 +166,7 @@ static inline void bio_advance(struct bio *bio, unsigned int nbytes) 
 */

#define bio_for_each_bvec_all(bvl, bio, i)		\

	for (i = 0, bvl = bio_first_bvec_all(bio);	\

	     i < (bio)->bi_vcnt; i++, bvl++)		\

	     i < (bio)->bi_vcnt; i++, bvl++)



#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
@@ -260,6 +260,57 @@ static inline struct bio_vec *bio_last_bvec_all(struct bio *bio) 
	return &bio->bi_io_vec[bio->bi_vcnt - 1];

}



/**

 * struct folio_iter - State for iterating all folios in a bio.

 * @folio: The current folio we're iterating.  NULL after the last folio.

 * @offset: The byte offset within the current folio.

 * @length: The number of bytes in this iteration (will not cross folio

 *	boundary).

 */

struct folio_iter {

	struct folio *folio;

	size_t offset;

	size_t length;

	/* private: for use by the iterator */

	size_t _seg_count;

	int _i;

};



static inline void bio_first_folio(struct folio_iter *fi, struct bio *bio,

				   int i)

{

	struct bio_vec *bvec = bio_first_bvec_all(bio) + i;



	fi->folio = page_folio(bvec->bv_page);

	fi->offset = bvec->bv_offset +

			PAGE_SIZE * (bvec->bv_page - &fi->folio->page);

	fi->_seg_count = bvec->bv_len;

	fi->length = min(folio_size(fi->folio) - fi->offset, fi->_seg_count);

	fi->_i = i;

}



static inline void bio_next_folio(struct folio_iter *fi, struct bio *bio)

{

	fi->_seg_count -= fi->length;

	if (fi->_seg_count) {

		fi->folio = folio_next(fi->folio);

		fi->offset = 0;

		fi->length = min(folio_size(fi->folio), fi->_seg_count);

	} else if (fi->_i + 1 < bio->bi_vcnt) {

		bio_first_folio(fi, bio, fi->_i + 1);

	} else {

		fi->folio = NULL;

	}

}



/**

 * bio_for_each_folio_all - Iterate over each folio in a bio.

 * @fi: struct folio_iter which is updated for each folio.

 * @bio: struct bio to iterate over.

 */

#define bio_for_each_folio_all(fi, bio)				\

	for (bio_first_folio(&fi, bio, 0); fi.folio; bio_next_folio(&fi, bio))



enum bip_flags {

	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */

	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */