[PATCH 3.16.y-ckt 146/185] 9p: forgetting to cancel request on interrupted zero-copy RPC

[Luis Henriques]

3.16.7-ckt15 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <viro at zeniv.linux.org.uk>

commit a84b69cb6e0a41e86bc593904faa6def3b957343 upstream.

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.

Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/9p/client.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 0004cbaac4a4..55a55ce92dc1 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -850,7 +850,8 @@ 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);