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>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 18f0a8dcc095..c59f3ca2b41b 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -280,7 +280,7 @@ rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
         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;
 }