Commit 076098e5 authored by Al Viro's avatar Al Viro
Browse files

bio_map_user_iov(): switch to iov_iter_get_pages()/iov_iter_advance() 



... and to hell with iov_for_each() nonsense

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 1cfd0ddd

block/bio.c

+24 −33
Original line number Diff line number Diff line
@@ -1328,7 +1328,7 @@ struct bio *bio_map_user_iov(struct request_queue *q, 
	struct page **pages;

	struct bio *bio;

	int cur_page = 0;

	int ret, offset;

	int ret;

	struct iov_iter i;

	struct iovec iov;

	struct bio_vec *bvec;
@@ -1365,43 +1365,32 @@ struct bio *bio_map_user_iov(struct request_queue *q, 
	if (!pages)

		goto out;



	iov_for_each(iov, i, *iter) {

		unsigned long uaddr = (unsigned long) iov.iov_base;

		unsigned long len = iov.iov_len;

		unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;

		unsigned long start = uaddr >> PAGE_SHIFT;

		const int local_nr_pages = end - start;

		const int page_limit = cur_page + local_nr_pages;



		ret = get_user_pages_fast(uaddr, local_nr_pages,

				(iter->type & WRITE) != WRITE,

				&pages[cur_page]);

		if (unlikely(ret < local_nr_pages)) {

			for (j = cur_page; j < page_limit; j++) {

				if (!pages[j])

					break;

				put_page(pages[j]);

			}

			ret = -EFAULT;

	i = *iter;

	while (iov_iter_count(&i)) {

		ssize_t bytes;

		size_t offs, added = 0;

		int npages;



		bytes = iov_iter_get_pages(&i, pages + cur_page, LONG_MAX,

						nr_pages - cur_page, &offs);

		if (unlikely(bytes <= 0)) {

			ret = bytes ? bytes : -EFAULT;

			goto out_unmap;

		}



		offset = offset_in_page(uaddr);

		for (j = cur_page; j < page_limit; j++) {

			unsigned int bytes = PAGE_SIZE - offset;

			unsigned short prev_bi_vcnt = bio->bi_vcnt;

		npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);



			if (len <= 0)

				break;

		for (j = cur_page; j < cur_page + npages; j++) {

			unsigned int n = PAGE_SIZE - offs;

			unsigned short prev_bi_vcnt = bio->bi_vcnt;



			if (bytes > len)

				bytes = len;

			if (n > bytes)

				n = bytes;



			/*

			 * sorry...

			 */

			if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <

					    bytes)

			if (bio_add_pc_page(q, bio, pages[j], n, offs) < n)

				break;



			/*
@@ -1411,16 +1400,18 @@ struct bio *bio_map_user_iov(struct request_queue *q, 
			if (bio->bi_vcnt == prev_bi_vcnt)

				put_page(pages[j]);



			len -= bytes;

			offset = 0;

			added += n;

			bytes -= n;

			offs = 0;

		}

		iov_iter_advance(&i, added);



		cur_page = j;

		/*

		 * release the pages we didn't map into the bio, if any

		 */

		while (j < page_limit)

		while (j < cur_page + npages)

			put_page(pages[j++]);

		cur_page = j;

	}



	kfree(pages);