[CIFS] Can't rely on iov length and base when kernel_recvmsg returns error

When retrying kernel_recvmsg, reset iov_base and iov_len.

Note comment from Sridhar: "In the normal path, iov.iov_len is clearly set to 4. But i think you are
running into a case where kernel_recvmsg() is called via 'goto incomplete_rcv'
It happens if the previous call fails with EAGAIN.
If you want to call recvmsg() after EAGAIN failure, you need to reset iov."

Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index e9f9248cb3fe..c682be8f2984 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -417,9 +417,14 @@ incomplete_rcv:
                         msleep(1); /* minimum sleep to prevent looping
                                 allowing socket to clear and app threads to set
                                 tcpStatus CifsNeedReconnect if server hung */
-                        if (pdu_length < 4)
+                        if (pdu_length < 4) {
+                                iov.iov_base = (4 - pdu_length) +
+                                                        (char *)smb_buffer;
+                                iov.iov_len = pdu_length;
+                                smb_msg.msg_control = NULL;
+                                smb_msg.msg_controllen = 0;
                                 goto incomplete_rcv;
-                        else
+                        } else
                                 continue;
                 } else if (length <= 0) {
                         if (server->tcpStatus == CifsNew) {