In netfs_extract_user_iter(), if iov_iter_extract_pages() failed to extract user pages, bail out on -ENOMEM, otherwise return the error code only if @npages == 0, allowing short DIO reads and writes to be issued. This fixes mmapstress02 from LTP tests against CIFS. Reported-by: Xiaoli Feng Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator") Signed-off-by: Paulo Alcantara (Red Hat) Reviewed-by: David Howells Cc: netfs@lists.linux.dev Cc: stable@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org --- fs/netfs/iterator.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index 72a435e5fc6d..dc1039b41cf4 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -22,7 +22,7 @@ * * Extract the page fragments from the given amount of the source iterator and * build up a second iterator that refers to all of those bits. This allows - * the original iterator to disposed of. + * the original iterator to be disposed of. * * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA be * allowed on the pages extracted. @@ -67,8 +67,8 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, ret = iov_iter_extract_pages(orig, &pages, count, max_pages - npages, extraction_flags, &offset); - if (ret < 0) { - pr_err("Couldn't get user pages (rc=%zd)\n", ret); + if (unlikely(ret <= 0)) { + ret = ret ?: -EIO; break; } @@ -97,6 +97,13 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, npages += cur_npages; } + if (ret < 0 && (ret == -ENOMEM || npages == 0)) { + for (i = 0; i < npages; i++) + unpin_user_page(bv[i].bv_page); + kvfree(bv); + return ret; + } + iov_iter_bvec(new, orig->data_source, bv, npages, orig_len - count); return npages; } -- 2.53.0