linux-kernel - [PATCH 5.4 094/203] xprtrdma: Fix completion wait during device removal

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Message-Id: <20200116231753.886716695@linuxfoundation.org>
Date:   Fri, 17 Jan 2020 00:16:51 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chuck Lever <chuck.lever@...cle.com>,
        Anna Schumaker <Anna.Schumaker@...app.com>
Subject: [PATCH 5.4 094/203] xprtrdma: Fix completion wait during device removal

From: Chuck Lever <chuck.lever@...cle.com>

commit 13cb886c591f341a8759f175292ddf978ef903a1 upstream.

I've found that on occasion, "rmmod <dev>" will hang while if an NFS
is under load.

Ensure that ri_remove_done is initialized only just before the
transport is woken up to force a close. This avoids the completion
possibly getting initialized again while the CM event handler is
waiting for a wake-up.

Fixes: bebd031866ca ("xprtrdma: Support unplugging an HCA from under an NFS mount")
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@...app.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/sunrpc/xprtrdma/verbs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -245,6 +245,7 @@ rpcrdma_cm_event_handler(struct rdma_cm_
 			ia->ri_id->device->name,
 			rpcrdma_addrstr(r_xprt), rpcrdma_portstr(r_xprt));
 #endif
+		init_completion(&ia->ri_remove_done);
 		set_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags);
 		ep->rep_connected = -ENODEV;
 		xprt_force_disconnect(xprt);
@@ -299,7 +300,6 @@ rpcrdma_create_id(struct rpcrdma_xprt *x
 	trace_xprtrdma_conn_start(xprt);
 
 	init_completion(&ia->ri_done);
-	init_completion(&ia->ri_remove_done);
 
 	id = rdma_create_id(xprt->rx_xprt.xprt_net, rpcrdma_cm_event_handler,
 			    xprt, RDMA_PS_TCP, IB_QPT_RC);