9p: forgetting to cancel request on interrupted zero-copy RPC

If we'd already sent a request and decide to abort it, we *must*
issue TFLUSH properly and not just blindly reuse the tag, or
we'll get seriously screwed when response eventually arrives
and we confuse it for response to later request that had reused
the same tag.

Cc: stable@vger.kernel.org # v3.2 and later
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/net/9p/client.c b/net/9p/client.c
index 6f4c4c8..28f36e4 100644 (file)
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -843,7 +843,8 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
        if (err < 0) {
                if (err == -EIO)
                        c->status = Disconnected;
-               goto reterr;
+               if (err != -ERESTARTSYS)
+                       goto reterr;
        }
        if (req->status == REQ_STATUS_ERROR) {
                p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);