From 9a6469060316674230c0666c5706f7097e9278bb Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 9 Jun 2022 10:37:57 -0400 Subject: [PATCH] block: convert to advancing variants of iov_iter_get_pages{,_alloc}() ... doing revert if we end up not using some pages Signed-off-by: Al Viro --- block/bio.c | 25 ++++++++++++++----------- block/blk-map.c | 7 ++++--- 2 files changed, 18 insertions(+), 14 deletions(-) diff --git a/block/bio.c b/block/bio.c index 082436736d69..d3bc05ed0783 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1200,7 +1200,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) struct page **pages = (struct page **)bv; ssize_t size, left; unsigned len, i; - size_t offset; + size_t offset, trim; int ret = 0; /* @@ -1218,16 +1218,19 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) * result to ensure the bio's total size is correct. The remainder of * the iov data will be picked up in the next bio iteration. */ - size = iov_iter_get_pages(iter, pages, UINT_MAX - bio->bi_iter.bi_size, + size = iov_iter_get_pages2(iter, pages, UINT_MAX - bio->bi_iter.bi_size, nr_pages, &offset); - if (size > 0) { - nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE); - size = ALIGN_DOWN(size, bdev_logical_block_size(bio->bi_bdev)); - } else - nr_pages = 0; - - if (unlikely(size <= 0)) { - ret = size ? size : -EFAULT; + if (unlikely(size <= 0)) + return size ? size : -EFAULT; + + nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE); + + trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1); + iov_iter_revert(iter, trim); + + size -= trim; + if (unlikely(!size)) { + ret = -EFAULT; goto out; } @@ -1246,7 +1249,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) offset = 0; } - iov_iter_advance(iter, size - left); + iov_iter_revert(iter, left); out: while (i < nr_pages) put_page(pages[i++]); diff --git a/block/blk-map.c b/block/blk-map.c index df8b066cd548..7196a6b64c80 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -254,7 +254,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter, size_t offs, added = 0; int npages; - bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs); + bytes = iov_iter_get_pages_alloc2(iter, &pages, LONG_MAX, &offs); if (unlikely(bytes <= 0)) { ret = bytes ? bytes : -EFAULT; goto out_unmap; @@ -284,7 +284,6 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter, bytes -= n; offs = 0; } - iov_iter_advance(iter, added); } /* * release the pages we didn't map into the bio, if any @@ -293,8 +292,10 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter, put_page(pages[j++]); kvfree(pages); /* couldn't stuff something into bio? */ - if (bytes) + if (bytes) { + iov_iter_revert(iter, bytes); break; + } } ret = blk_rq_append_bio(rq, bio); -- 2.36.1