xprtrdma: Fix corner cases when handling device removal

Michal Kalderon has found some corner cases around device unload
with active NFS mounts that I didn't have the imagination to test
when xprtrdma device removal was added last year.

- The ULP device removal handler is responsible for deallocating
  the PD. That wasn't clear to me initially, and my own testing
  suggested it was not necessary, but that is incorrect.

- The transport destruction path can no longer assume that there
  is a valid ID.

- When destroying a transport, ensure that ib_free_cq() is not
  invoked on a CQ that was already released.

Reported-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Fixes: bebd031866ca ("xprtrdma: Support unplugging an HCA from ...")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 6a7a5a277e75..fe5eaca2d197 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -250,7 +250,6 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
                 wait_for_completion(&ia->ri_remove_done);
 
                 ia->ri_id = NULL;
-                ia->ri_pd = NULL;
                 ia->ri_device = NULL;
                 /* Return 1 to ensure the core destroys the id. */
                 return 1;
@@ -447,7 +446,9 @@ rpcrdma_ia_remove(struct rpcrdma_ia *ia)
                 ia->ri_id->qp = NULL;
         }
         ib_free_cq(ep->rep_attr.recv_cq);
+        ep->rep_attr.recv_cq = NULL;
         ib_free_cq(ep->rep_attr.send_cq);
+        ep->rep_attr.send_cq = NULL;
 
         /* The ULP is responsible for ensuring all DMA
          * mappings and MRs are gone.
@@ -460,6 +461,8 @@ rpcrdma_ia_remove(struct rpcrdma_ia *ia)
                 rpcrdma_dma_unmap_regbuf(req->rl_recvbuf);
         }
         rpcrdma_mrs_destroy(buf);
+        ib_dealloc_pd(ia->ri_pd);
+        ia->ri_pd = NULL;
 
         /* Allow waiters to continue */
         complete(&ia->ri_remove_done);
@@ -627,14 +630,16 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 {
         cancel_delayed_work_sync(&ep->rep_connect_worker);
 
-        if (ia->ri_id->qp) {
+        if (ia->ri_id && ia->ri_id->qp) {
                 rpcrdma_ep_disconnect(ep, ia);
                 rdma_destroy_qp(ia->ri_id);
                 ia->ri_id->qp = NULL;
         }
 
-        ib_free_cq(ep->rep_attr.recv_cq);
-        ib_free_cq(ep->rep_attr.send_cq);
+        if (ep->rep_attr.recv_cq)
+                ib_free_cq(ep->rep_attr.recv_cq);
+        if (ep->rep_attr.send_cq)
+                ib_free_cq(ep->rep_attr.send_cq);
 }
 
 /* Re-establish a connection after a device removal event.