Commit 38f2dd34 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

ublk: support to copy any part of request pages 



Add 'offset' to 'struct ublk_map_data', so that ublk_copy_user_pages()
can be used to copy any sub-buffer(linear mapped) of the request.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230519065030.351216-6-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 82840669

drivers/block/ublk_drv.c

+24 −7
Original line number Diff line number Diff line
@@ -505,19 +505,36 @@ static void ublk_copy_io_pages(struct ublk_io_iter *data, 
	}

}



static bool ublk_advance_io_iter(const struct request *req,

		struct ublk_io_iter *iter, unsigned int offset)

{

	struct bio *bio = req->bio;



	for_each_bio(bio) {

		if (bio->bi_iter.bi_size > offset) {

			iter->bio = bio;

			iter->iter = bio->bi_iter;

			bio_advance_iter(iter->bio, &iter->iter, offset);

			return true;

		}

		offset -= bio->bi_iter.bi_size;

	}

	return false;

}



/*

 * Copy data between request pages and io_iter, and 'offset'

 * is the start point of linear offset of request.

 */

static size_t ublk_copy_user_pages(const struct request *req,

		struct iov_iter *uiter, int dir)

		unsigned offset, struct iov_iter *uiter, int dir)

{

	struct ublk_io_iter iter = {

		.bio	= req->bio,

		.iter	= req->bio->bi_iter,

	};

	struct ublk_io_iter iter;

	size_t done = 0;



	if (!ublk_advance_io_iter(req, &iter, offset))

		return 0;



	while (iov_iter_count(uiter) && iter.bio) {

		unsigned nr_pages;

		size_t len, off;
@@ -570,7 +587,7 @@ static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req, 
		import_single_range(dir, u64_to_user_ptr(io->addr), rq_bytes,

				&iov, &iter);



		return ublk_copy_user_pages(req, &iter, dir);

		return ublk_copy_user_pages(req, 0, &iter, dir);

	}

	return rq_bytes;

}
@@ -590,7 +607,7 @@ static int ublk_unmap_io(const struct ublk_queue *ubq, 


		import_single_range(dir, u64_to_user_ptr(io->addr), io->res,

				&iov, &iter);

		return ublk_copy_user_pages(req, &iter, dir);

		return ublk_copy_user_pages(req, 0, &iter, dir);

	}

	return rq_bytes;

}