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Commit 9124d3fe authored by Dongsu Park's avatar Dongsu Park Committed by Jens Axboe
Browse files

block: rewrite and split __bio_copy_iov() 



Rewrite __bio_copy_iov using the copy_page_{from,to}_iter helpers, and
split it into two simpler functions.

This commit should contain only literal replacements, without
functional changes.

Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarDongsu Park <dongsu.park@profitbricks.com>
[hch: removed the __bio_copy_iov wrapper]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMing Lei <tom.leiming@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 37f19e57

block/bio.c

+56 −34
Original line number Diff line number Diff line
@@ -1036,43 +1036,66 @@ static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count, 
		       sizeof(struct iovec) * iov_count, gfp_mask);

}



static int __bio_copy_iov(struct bio *bio, const struct iov_iter *iter,

			  int to_user, int from_user)

/**

 * bio_copy_from_iter - copy all pages from iov_iter to bio

 * @bio: The &struct bio which describes the I/O as destination

 * @iter: iov_iter as source

 *

 * Copy all pages from iov_iter to bio.

 * Returns 0 on success, or error on failure.

 */

static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter)

{

	int ret = 0, i;

	int i;

	struct bio_vec *bvec;

	struct iov_iter iov_iter = *iter;



	bio_for_each_segment_all(bvec, bio, i) {

		char *bv_addr = page_address(bvec->bv_page);

		unsigned int bv_len = bvec->bv_len;



		while (bv_len && iov_iter.count) {

			struct iovec iov = iov_iter_iovec(&iov_iter);

			unsigned int bytes = min_t(unsigned int, bv_len,

						   iov.iov_len);



			if (!ret) {

				if (to_user)

					ret = copy_to_user(iov.iov_base,

							   bv_addr, bytes);



				if (from_user)

					ret = copy_from_user(bv_addr,

							     iov.iov_base,

							     bytes);

		ssize_t ret;



				if (ret)

					ret = -EFAULT;

		ret = copy_page_from_iter(bvec->bv_page,

					  bvec->bv_offset,

					  bvec->bv_len,

					  &iter);



		if (!iov_iter_count(&iter))

			break;



		if (ret < bvec->bv_len)

			return -EFAULT;

	}



			bv_len -= bytes;

			bv_addr += bytes;

			iov_iter_advance(&iov_iter, bytes);

	return 0;

}



/**

 * bio_copy_to_iter - copy all pages from bio to iov_iter

 * @bio: The &struct bio which describes the I/O as source

 * @iter: iov_iter as destination

 *

 * Copy all pages from bio to iov_iter.

 * Returns 0 on success, or error on failure.

 */

static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)

{

	int i;

	struct bio_vec *bvec;



	bio_for_each_segment_all(bvec, bio, i) {

		ssize_t ret;



		ret = copy_page_to_iter(bvec->bv_page,

					bvec->bv_offset,

					bvec->bv_len,

					&iter);



		if (!iov_iter_count(&iter))

			break;



		if (ret < bvec->bv_len)

			return -EFAULT;

	}



	return ret;

	return 0;

}



static void bio_free_pages(struct bio *bio)
@@ -1101,9 +1124,8 @@ int bio_uncopy_user(struct bio *bio) 
		 * if we're in a workqueue, the request is orphaned, so

		 * don't copy into a random user address space, just free.

		 */

		if (current->mm)

			ret = __bio_copy_iov(bio, &bmd->iter,

					     bio_data_dir(bio) == READ, 0);

		if (current->mm && bio_data_dir(bio) == READ)

			ret = bio_copy_to_iter(bio, bmd->iter);

		if (bmd->is_our_pages)

			bio_free_pages(bio);

	}
@@ -1228,7 +1250,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 
	 */

	if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||

	    (map_data && map_data->from_user)) {

		ret = __bio_copy_iov(bio, iter, 0, 1);

		ret = bio_copy_from_iter(bio, *iter);

		if (ret)

			goto cleanup;

	}