2023-12-13 19:49:40

by Benjamin Coddington

[permalink] [raw]
Subject: [PATCH v3 1/2] SUNRPC: Fixup v4.1 backchannel request timeouts

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.

Initialize the backchannel's rpc_rqst timeout parameters from the xprt's
default timeout settings.

Fixes: 59464b262ff5 ("SUNRPC: SOFTCONN tasks should time out when on the sending list")
Signed-off-by: Benjamin Coddington <[email protected]>
---
net/sunrpc/xprt.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 2364c485540c..6cc9ffac962d 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -651,9 +651,9 @@ 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)
@@ -665,9 +665,10 @@ 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)
@@ -675,7 +676,8 @@ 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;
@@ -684,8 +686,9 @@ 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;
}

@@ -713,7 +716,7 @@ 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);
@@ -1886,7 +1889,7 @@ 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);
}
@@ -1996,6 +1999,8 @@ 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->timeout);
}
#endif

--
2.43.0



2024-01-04 13:37:30

by Jeffrey Layton

[permalink] [raw]
Subject: Re: [PATCH v3 1/2] SUNRPC: Fixup v4.1 backchannel request timeouts

On Wed, 2023-12-13 at 14:49 -0500, Benjamin Coddington wrote:
> 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.
>
> Initialize the backchannel's rpc_rqst timeout parameters from the xprt's
> default timeout settings.
>
> Fixes: 59464b262ff5 ("SUNRPC: SOFTCONN tasks should time out when on the sending list")
> Signed-off-by: Benjamin Coddington <[email protected]>
> ---
> net/sunrpc/xprt.c | 23 ++++++++++++++---------
> 1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
> index 2364c485540c..6cc9ffac962d 100644
> --- a/net/sunrpc/xprt.c
> +++ b/net/sunrpc/xprt.c
> @@ -651,9 +651,9 @@ 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)
> @@ -665,9 +665,10 @@ 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)
> @@ -675,7 +676,8 @@ 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;
> @@ -684,8 +686,9 @@ 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;
> }
>
> @@ -713,7 +716,7 @@ 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);
> @@ -1886,7 +1889,7 @@ 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);
> }
> @@ -1996,6 +1999,8 @@ 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->timeout);
> }
> #endif
>

As I mentioned in the email thread here, I've been seeing some hangs
with v6.7-rc8 kernels when testing TLS support:

https://lore.kernel.org/linux-nfs/[email protected]/T/#t

With this patchset in place, I've been unable to reproduce it.


I'm not sure if this is the right way to fix this, but this does seem to
be a real problem and I have a semi-reliable way to reproduce it if you
need me to test a fix for it.

Cheers,
--
Jeff Layton <[email protected]>