sunrpc: rpc_pipe_poll may miss available data in some cases
Pipe messages start out life on a queue on the inode, but when first
read they're moved to the filp's private pointer. So it's possible for
a poll here to return null even though there's a partially read message
available.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 18f0a8d..c59f3ca 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -280,7 +280,7 @@
mask = POLLOUT | POLLWRNORM;
if (rpci->ops == NULL)
mask |= POLLERR | POLLHUP;
- if (!list_empty(&rpci->pipe))
+ if (filp->private_data || !list_empty(&rpci->pipe))
mask |= POLLIN | POLLRDNORM;
return mask;
}