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Commit ec62f40d authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
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xprtrdma: Ensure ia->ri_id->qp is not NULL when reconnecting 



Devesh Sharma <Devesh.Sharma@Emulex.Com> reports that after a
disconnect, his HCA is failing to create a fresh QP, leaving
ia_ri->ri_id->qp set to NULL. But xprtrdma still allows RPCs to
wake up and post LOCAL_INV as they exit, causing an oops.

rpcrdma_ep_connect() is allowing the wake-up by leaking the QP
creation error code (-EPERM in this case) to the RPC client's
generic layer. xprt_connect_status() does not recognize -EPERM, so
it kills pending RPC tasks immediately rather than retrying the
connect.

Re-arrange the QP creation logic so that when it fails on reconnect,
it leaves ->qp with the old QP rather than NULL.  If pending RPC
tasks wake and exit, LOCAL_INV work requests will flush rather than
oops.

On initial connect, leaving ->qp == NULL is OK, since there are no
pending RPCs that might use ->qp. But be sure not to try to destroy
a NULL QP when rpcrdma_ep_connect() is retried.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 65866f82

net/sunrpc/xprtrdma/verbs.c

+20 −9
Original line number Diff line number Diff line
@@ -867,6 +867,7 @@ rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) 
	if (ep->rep_connected != 0) {

		struct rpcrdma_xprt *xprt;

retry:

		dprintk("RPC:       %s: reconnecting...\n", __func__);

		rc = rpcrdma_ep_disconnect(ep, ia);

		if (rc && rc != -ENOTCONN)

			dprintk("RPC:       %s: rpcrdma_ep_disconnect"
@@ -879,7 +880,7 @@ rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) 
		id = rpcrdma_create_id(xprt, ia,

				(struct sockaddr *)&xprt->rx_data.addr);

		if (IS_ERR(id)) {

			rc = PTR_ERR(id);

			rc = -EHOSTUNREACH;

			goto out;

		}

		/* TEMP TEMP TEMP - fail if new device:
@@ -893,20 +894,30 @@ rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) 
			printk("RPC:       %s: can't reconnect on "

				"different device!\n", __func__);

			rdma_destroy_id(id);

			rc = -ENETDOWN;

			rc = -ENETUNREACH;

			goto out;

		}

		/* END TEMP */

		rc = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);

		if (rc) {

			dprintk("RPC:       %s: rdma_create_qp failed %i\n",

				__func__, rc);

			rdma_destroy_id(id);

			rc = -ENETUNREACH;

			goto out;

		}

		rdma_destroy_qp(ia->ri_id);

		rdma_destroy_id(ia->ri_id);

		ia->ri_id = id;

	}



	} else {

		dprintk("RPC:       %s: connecting...\n", __func__);

		rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);

		if (rc) {

			dprintk("RPC:       %s: rdma_create_qp failed %i\n",

				__func__, rc);

		goto out;

			/* do not update ep->rep_connected */

			return -ENETUNREACH;

		}

	}



/* XXX Tavor device performs badly with 2K MTU! */