NFS/RDMA Release resources in svcrdma when device is removed

[ Queued for upstream v4.3 ]

When removing underlying RDMA device, the rmmod will hang forever if there
are any outstanding NFS/RDMA client mounts. The outstanding NFS/RDMA counts
could also prevent the server from shutting down. Further debugging shows
that the existing connections are not teared down and resource are not
released when receiving RDMA_CM_EVENT_DEVICE_REMOVAL event. It seems the
original code missing svc_xprt_put() in RDMA_CM_EVENT_REMOVAL event handler
thus svc_xprt_free is never invoked to release the existing connection
resources.

The patch has been passed removing, adding device back and forth without
stopping NFS/RDMA service. This will also allow a device to be unplugged
and swapped out without shutting down NFS service.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=252
Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 3b4c2ff66a2f7376f8a721585fbecbd97c1fd187..1e64e1bdb275987a90679189953ff324b79d5840 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -653,6 +653,7 @@ static int rdma_cma_handler(struct rdma_cm_id *cma_id,
                if (xprt) {
                        set_bit(XPT_CLOSE, &xprt->xpt_flags);
                        svc_xprt_enqueue(xprt);
+                       svc_xprt_put(xprt);
                }
                break;
        default: