SUNRPC: Eliminate task->tk_xprt accesses that bypass rcu_dereference()

tk_xprt is just a shortcut for tk_client->cl_xprt, however cl_xprt is
defined as an __rcu variable. Replace dereferences of tk_xprt with
non-rcu dereferences where it is safe to do so.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/auth_gss/auth_gss.c

@@ -1154,7 +1154,7 @@ gss_marshal(struct rpc_task *task, __be32 *p)
 
 	/* We compute the checksum for the verifier over the xdr-encoded bytes
 	 * starting with the xid and ending at the end of the credential: */
-	iov.iov_base = xprt_skip_transport_header(task->tk_xprt,
+	iov.iov_base = xprt_skip_transport_header(req->rq_xprt,
 					req->rq_snd_buf.head[0].iov_base);
 	iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
 	xdr_buf_from_iov(&iov, &verf_buf);

net/sunrpc/clnt.c

@@ -1400,7 +1400,7 @@ call_allocate(struct rpc_task *task)
 {
 	unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
 	struct rpc_rqst *req = task->tk_rqstp;
-	struct rpc_xprt *xprt = task->tk_xprt;
+	struct rpc_xprt *xprt = req->rq_xprt;
 	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 
 	dprint_status(task);
@@ -1685,7 +1685,7 @@ call_transmit(struct rpc_task *task)
 	if (rpc_reply_expected(task))
 		return;
 	task->tk_action = rpc_exit_task;
-	rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
+	rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
 }
 
 /*
@@ -1784,7 +1784,7 @@ call_bc_transmit(struct rpc_task *task)
 		 */
 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
 			"error: %d\n", task->tk_status);
-		xprt_conditional_disconnect(task->tk_xprt,
+		xprt_conditional_disconnect(req->rq_xprt,
 			req->rq_connect_cookie);
 		break;
 	default:
@@ -1836,7 +1836,7 @@ call_status(struct rpc_task *task)
 	case -ETIMEDOUT:
 		task->tk_action = call_timeout;
 		if (task->tk_client->cl_discrtry)
-			xprt_conditional_disconnect(task->tk_xprt,
+			xprt_conditional_disconnect(req->rq_xprt,
 					req->rq_connect_cookie);
 		break;
 	case -ECONNRESET:
@@ -1991,7 +1991,7 @@ call_decode(struct rpc_task *task)
 	if (task->tk_rqstp == req) {
 		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
 		if (task->tk_client->cl_discrtry)
-			xprt_conditional_disconnect(task->tk_xprt,
+			xprt_conditional_disconnect(req->rq_xprt,
 					req->rq_connect_cookie);
 	}
 }
@@ -2005,7 +2005,7 @@ rpc_encode_header(struct rpc_task *task)
 
 	/* FIXME: check buffer size? */
 
-	p = xprt_skip_transport_header(task->tk_xprt, p);
+	p = xprt_skip_transport_header(req->rq_xprt, p);
 	*p++ = req->rq_xid;		/* XID */
 	*p++ = htonl(RPC_CALL);		/* CALL */
 	*p++ = htonl(RPC_VERSION);	/* RPC version */

net/sunrpc/xprt.c

@@ -430,7 +430,9 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
  */
 void xprt_release_rqst_cong(struct rpc_task *task)
 {
-	__xprt_put_cong(task->tk_xprt, task->tk_rqstp);
+	struct rpc_rqst *req = task->tk_rqstp;
+
+	__xprt_put_cong(req->rq_xprt, req);
 }
 EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
 

net/sunrpc/xprtrdma/rpc_rdma.c

@@ -171,7 +171,7 @@ rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
 		struct rpcrdma_msg *headerp, enum rpcrdma_chunktype type)
 {
 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
-	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_task->tk_xprt);
+	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
 	int nsegs, nchunks = 0;
 	unsigned int pos;
 	struct rpcrdma_mr_seg *seg = req->rl_segments;
@@ -366,7 +366,7 @@ rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
 int
 rpcrdma_marshal_req(struct rpc_rqst *rqst)
 {
-	struct rpc_xprt *xprt = rqst->rq_task->tk_xprt;
+	struct rpc_xprt *xprt = rqst->rq_xprt;
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
 	char *base;

net/sunrpc/xprtrdma/transport.c

@@ -475,7 +475,7 @@ xprt_rdma_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 static void *
 xprt_rdma_allocate(struct rpc_task *task, size_t size)
 {
-	struct rpc_xprt *xprt = task->tk_xprt;
+	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
 	struct rpcrdma_req *req, *nreq;
 
 	req = rpcrdma_buffer_get(&rpcx_to_rdmax(xprt)->rx_buf);
@@ -627,7 +627,7 @@ static int
 xprt_rdma_send_request(struct rpc_task *task)
 {
 	struct rpc_rqst *rqst = task->tk_rqstp;
-	struct rpc_xprt *xprt = task->tk_xprt;
+	struct rpc_xprt *xprt = rqst->rq_xprt;
 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -235,13 +235,13 @@ struct rpcrdma_create_data_internal {
 };
 
 #define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
-	(rpcx_to_rdmad(rq->rq_task->tk_xprt).inline_rsize)
+	(rpcx_to_rdmad(rq->rq_xprt).inline_rsize)
 
 #define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
-	(rpcx_to_rdmad(rq->rq_task->tk_xprt).inline_wsize)
+	(rpcx_to_rdmad(rq->rq_xprt).inline_wsize)
 
 #define RPCRDMA_INLINE_PAD_VALUE(rq)\
-	rpcx_to_rdmad(rq->rq_task->tk_xprt).padding
+	rpcx_to_rdmad(rq->rq_xprt).padding
 
 /*
  * Statistics for RPCRDMA

net/sunrpc/xprtsock.c

@@ -770,7 +770,7 @@ static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 		goto out_release;
 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
 		goto out_release;
-	set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
+	set_bit(XPRT_CLOSE_WAIT, &xprt->state);
 out_release:
 	xprt_release_xprt(xprt, task);
 }