[PATCH v2] SUNRPC: Fixup v4.1 backchannel request timeouts

[Benjamin Coddington <bcodding@xxxxxxxxxx>]

After commit 59464b262ff5 ("SUNRPC: SOFTCONN tasks should time out when on
the sending list"), any 4.1 backchannel tasks placed on the sending queue
would immediately return with -ETIMEDOUT since their req timers are zero.
We can fix this by keeping a copy of the rpc_clnt's timeout params on the
transport and using them to properly setup the timeouts on the v4.1
backchannel tasks' req.

Fixes: 59464b262ff5 ("SUNRPC: SOFTCONN tasks should time out when on the sending list")
Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
---
 include/linux/sunrpc/xprt.h |  1 +
 net/sunrpc/clnt.c           |  3 +++
 net/sunrpc/xprt.c           | 23 ++++++++++++++---------
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index f85d3a0daca2..7565902053f3 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -285,6 +285,7 @@ struct rpc_xprt {
 						 * items */
 	struct list_head	bc_pa_list;	/* List of preallocated
 						 * backchannel rpc_rqst's */
+	struct rpc_timeout	bc_timeout;	/* backchannel timeout params */
 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 
 	struct rb_root		recv_queue;	/* Receive queue */
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index d6805c1268a7..5891757c88b1 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -279,6 +279,9 @@ static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
 		clnt->cl_autobind = 1;
 
 	clnt->cl_timeout = timeout;
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+	memcpy(&xprt->bc_timeout, timeout, sizeof(struct rpc_timeout));
+#endif
 	rcu_assign_pointer(clnt->cl_xprt, xprt);
 	spin_unlock(&clnt->cl_lock);
 
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 92301e32cda4..7dce780869fc 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -653,9 +653,9 @@ static unsigned long xprt_abs_ktime_to_jiffies(ktime_t abstime)
 		jiffies + nsecs_to_jiffies(-delta);
 }
 
-static unsigned long xprt_calc_majortimeo(struct rpc_rqst *req)
+static unsigned long xprt_calc_majortimeo(struct rpc_rqst *req,
+		const struct rpc_timeout *to)
 {
-	const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
 	unsigned long majortimeo = req->rq_timeout;
 
 	if (to->to_exponential)
@@ -667,9 +667,10 @@ static unsigned long xprt_calc_majortimeo(struct rpc_rqst *req)
 	return majortimeo;
 }
 
-static void xprt_reset_majortimeo(struct rpc_rqst *req)
+static void xprt_reset_majortimeo(struct rpc_rqst *req,
+		const struct rpc_timeout *to)
 {
-	req->rq_majortimeo += xprt_calc_majortimeo(req);
+	req->rq_majortimeo += xprt_calc_majortimeo(req, to);
 }
 
 static void xprt_reset_minortimeo(struct rpc_rqst *req)
@@ -677,7 +678,8 @@ static void xprt_reset_minortimeo(struct rpc_rqst *req)
 	req->rq_minortimeo += req->rq_timeout;
 }
 
-static void xprt_init_majortimeo(struct rpc_task *task, struct rpc_rqst *req)
+static void xprt_init_majortimeo(struct rpc_task *task, struct rpc_rqst *req,
+		const struct rpc_timeout *to)
 {
 	unsigned long time_init;
 	struct rpc_xprt *xprt = req->rq_xprt;
@@ -686,8 +688,9 @@ static void xprt_init_majortimeo(struct rpc_task *task, struct rpc_rqst *req)
 		time_init = jiffies;
 	else
 		time_init = xprt_abs_ktime_to_jiffies(task->tk_start);
-	req->rq_timeout = task->tk_client->cl_timeout->to_initval;
-	req->rq_majortimeo = time_init + xprt_calc_majortimeo(req);
+
+	req->rq_timeout = to->to_initval;
+	req->rq_majortimeo = time_init + xprt_calc_majortimeo(req, to);
 	req->rq_minortimeo = time_init + req->rq_timeout;
 }
 
@@ -715,7 +718,7 @@ int xprt_adjust_timeout(struct rpc_rqst *req)
 	} else {
 		req->rq_timeout = to->to_initval;
 		req->rq_retries = 0;
-		xprt_reset_majortimeo(req);
+		xprt_reset_majortimeo(req, to);
 		/* Reset the RTT counters == "slow start" */
 		spin_lock(&xprt->transport_lock);
 		rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
@@ -1888,7 +1891,7 @@ xprt_request_init(struct rpc_task *task)
 	req->rq_snd_buf.bvec = NULL;
 	req->rq_rcv_buf.bvec = NULL;
 	req->rq_release_snd_buf = NULL;
-	xprt_init_majortimeo(task, req);
+	xprt_init_majortimeo(task, req, task->tk_client->cl_timeout);
 
 	trace_xprt_reserve(req);
 }
@@ -1998,6 +2001,8 @@ xprt_init_bc_request(struct rpc_rqst *req, struct rpc_task *task)
 	 */
 	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
 		xbufp->tail[0].iov_len;
+
+	xprt_init_majortimeo(task, req, &req->rq_xprt->bc_timeout);
 }
 #endif
 
-- 
2.43.0