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Commit 054bdf64 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

block: Add bio_advance() 



This is prep work for immutable bio vecs; we first want to centralize
where bvecs are modified.

Next two patches convert some existing code to use this function.

Signed-off-by: default avatarKent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
parent 9f060e22

fs/bio.c

+41 −0
Original line number Original line Diff line number Diff line
@@ -752,6 +752,47 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len, 
}

}

EXPORT_SYMBOL(bio_add_page);

EXPORT_SYMBOL(bio_add_page);





/**

 * bio_advance - increment/complete a bio by some number of bytes

 * @bio:	bio to advance

 * @bytes:	number of bytes to complete

 *

 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to

 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will

 * be updated on the last bvec as well.

 *

 * @bio will then represent the remaining, uncompleted portion of the io.

 */

void bio_advance(struct bio *bio, unsigned bytes)

{

	if (bio_integrity(bio))

		bio_integrity_advance(bio, bytes);



	bio->bi_sector += bytes >> 9;

	bio->bi_size -= bytes;



	if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)

		return;



	while (bytes) {

		if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {

			WARN_ONCE(1, "bio idx %d >= vcnt %d\n",

				  bio->bi_idx, bio->bi_vcnt);

			break;

		}



		if (bytes >= bio_iovec(bio)->bv_len) {

			bytes -= bio_iovec(bio)->bv_len;

			bio->bi_idx++;

		} else {

			bio_iovec(bio)->bv_len -= bytes;

			bio_iovec(bio)->bv_offset += bytes;

			bytes = 0;

		}

	}

}

EXPORT_SYMBOL(bio_advance);



struct bio_map_data {

struct bio_map_data {

	struct bio_vec *iovecs;

	struct bio_vec *iovecs;

	struct sg_iovec *sgvecs;

	struct sg_iovec *sgvecs;

include/linux/bio.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -248,6 +248,8 @@ extern void bio_endio(struct bio *, int); 
struct request_queue;

struct request_queue;

extern int bio_phys_segments(struct request_queue *, struct bio *);

extern int bio_phys_segments(struct request_queue *, struct bio *);





extern void bio_advance(struct bio *, unsigned);



extern void bio_init(struct bio *);

extern void bio_init(struct bio *);

extern void bio_reset(struct bio *);

extern void bio_reset(struct bio *);

include/linux/blk_types.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -197,6 +197,8 @@ enum rq_flag_bits { 
	 REQ_SECURE)

	 REQ_SECURE)

#define REQ_CLONE_MASK		REQ_COMMON_MASK

#define REQ_CLONE_MASK		REQ_COMMON_MASK





#define BIO_NO_ADVANCE_ITER_MASK	(REQ_DISCARD|REQ_WRITE_SAME)



/* This mask is used for both bio and request merge checking */

/* This mask is used for both bio and request merge checking */

#define REQ_NOMERGE_FLAGS \

#define REQ_NOMERGE_FLAGS \

	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)

	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)