Commit 10b1e59c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: add a bdev_rw_virt helper 



Add a helper to perform synchronous I/O on a kernel direct map range.
Currently this is implemented in various places in usually not very
efficient ways, so provide a generic helper instead.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250507120451.4000627-3-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 850e210d

block/bio.c

+30 −0
Original line number Diff line number Diff line
@@ -1319,6 +1319,36 @@ int submit_bio_wait(struct bio *bio) 
}

EXPORT_SYMBOL(submit_bio_wait);



/**

 * bdev_rw_virt - synchronously read into / write from kernel mapping

 * @bdev:	block device to access

 * @sector:	sector to access

 * @data:	data to read/write

 * @len:	length in byte to read/write

 * @op:		operation (e.g. REQ_OP_READ/REQ_OP_WRITE)

 *

 * Performs synchronous I/O to @bdev for @data/@len.  @data must be in

 * the kernel direct mapping and not a vmalloc address.

 */

int bdev_rw_virt(struct block_device *bdev, sector_t sector, void *data,

		size_t len, enum req_op op)

{

	struct bio_vec bv;

	struct bio bio;

	int error;



	if (WARN_ON_ONCE(is_vmalloc_addr(data)))

		return -EIO;



	bio_init(&bio, bdev, &bv, 1, op);

	bio.bi_iter.bi_sector = sector;

	bio_add_virt_nofail(&bio, data, len);

	error = submit_bio_wait(&bio);

	bio_uninit(&bio);

	return error;

}

EXPORT_SYMBOL_GPL(bdev_rw_virt);



static void bio_wait_end_io(struct bio *bio)

{

	complete(bio->bi_private);

include/linux/bio.h

+4 −1
Original line number Diff line number Diff line
@@ -402,7 +402,6 @@ static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs) 


struct request_queue;



extern int submit_bio_wait(struct bio *bio);

void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table,

	      unsigned short max_vecs, blk_opf_t opf);

extern void bio_uninit(struct bio *);
@@ -419,6 +418,10 @@ void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len, 
			  size_t off);

void bio_add_virt_nofail(struct bio *bio, void *vaddr, unsigned len);



int submit_bio_wait(struct bio *bio);

int bdev_rw_virt(struct block_device *bdev, sector_t sector, void *data,

		size_t len, enum req_op op);



int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);

void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter);

void __bio_release_pages(struct bio *bio, bool mark_dirty);