SUNRPC: Fix Oopsable condition in rpc_pipefs

 The elements on rpci->in_upcall are tracked by the filp->private_data,
 which will ensure that they get released when the file is closed.

 The exception is if rpc_close_pipes() gets called first, since that
 sets rpci->ops to NULL.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/rpc_pipe.c

@@ -59,7 +59,6 @@ __rpc_purge_upcall(struct inode *inode, int err)
 	struct rpc_inode *rpci = RPC_I(inode);
 
 	__rpc_purge_list(rpci, &rpci->pipe, err);
-	__rpc_purge_list(rpci, &rpci->in_upcall, err);
 	rpci->pipelen = 0;
 	wake_up(&rpci->waitq);
 }
@@ -119,6 +118,7 @@ rpc_close_pipes(struct inode *inode)
 	down(&inode->i_sem);
 	if (rpci->ops != NULL) {
 		rpci->nreaders = 0;
+		__rpc_purge_list(rpci, &rpci->in_upcall, -EPIPE);
 		__rpc_purge_upcall(inode, -EPIPE);
 		rpci->nwriters = 0;
 		if (rpci->ops->release_pipe)