From mboxrd@z Thu Jan 1 00:00:00 1970 From: Long Li Subject: [PATCH] CIFS: use the correct length when pinning memory for direct I/O for write Date: Sun, 16 Dec 2018 23:17:04 +0000 Message-ID: <20181216231704.16761-1-longli@linuxonhyperv.com> Reply-To: longli@microsoft.com Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: Steve French , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org Cc: Long Li , stable@vger.kernel.org List-Id: linux-rdma@vger.kernel.org From: Long Li The current code attempts to pin memory using the largest possible wsize based on the currect SMB credits. This doesn't cause kernel oops but this is not optimal as we may pin more pages then actually needed. Fix this by only pinning what are needed for doing this write I/O. Signed-off-by: Long Li Cc: stable@vger.kernel.org --- fs/cifs/file.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 3467351..c23bf9d 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2617,11 +2617,13 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from, if (rc) break; + cur_len = min_t(const size_t, len, wsize); + if (ctx->direct_io) { ssize_t result; result = iov_iter_get_pages_alloc( - from, &pagevec, wsize, &start); + from, &pagevec, cur_len, &start); if (result < 0) { cifs_dbg(VFS, "direct_writev couldn't get user pages " -- 2.7.4