| Message ID | 20240619135107.176384-2-cel@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] SUNRPC: Fix backchannel reply, again | expand |
On 19 Jun 2024, at 9:51, cel@kernel.org wrote: > From: Chuck Lever <chuck.lever@oracle.com> > > I still see "RPC: Could not send backchannel reply error: -110" > quite often, along with slow-running tests. Debugging shows that the > backchannel is still stumbling when it has to queue a callback reply > on a busy transport. > > Note that every one of these timeouts causes a connection loss by > virtue of the xprt_conditional_disconnect() call in that arm of > call_cb_transmit_status(). > > I found that setting to_maxval is necessary to get the RPC timeout > logic to behave whenever to_exponential is not set. > > Fixes: 57331a59ac0d ("NFSv4.1: Use the nfs_client's rpc timeouts for backchannel") > Signed-off-by: Chuck Lever <chuck.lever@oracle.com> That makes sense - I guess we were getting some random stack value in there? Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Ben > --- > net/sunrpc/svc.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c > index 965a27806bfd..e03f14024e47 100644 > --- a/net/sunrpc/svc.c > +++ b/net/sunrpc/svc.c > @@ -1588,9 +1588,11 @@ void svc_process(struct svc_rqst *rqstp) > */ > void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp) > { > + struct rpc_timeout timeout = { > + .to_increment = 0, > + }; > struct rpc_task *task; > int proc_error; > - struct rpc_timeout timeout; > > /* Build the svc_rqst used by the common processing routine */ > rqstp->rq_xid = req->rq_xid; > @@ -1643,6 +1645,7 @@ void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp) > timeout.to_initval = req->rq_xprt->timeout->to_initval; > timeout.to_retries = req->rq_xprt->timeout->to_retries; > } > + timeout.to_maxval = timeout.to_initval; > memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf)); > task = rpc_run_bc_task(req, &timeout); > > -- > 2.45.1
On Thu, Jun 20, 2024 at 07:41:21AM -0400, Benjamin Coddington wrote: > On 19 Jun 2024, at 9:51, cel@kernel.org wrote: > > > From: Chuck Lever <chuck.lever@oracle.com> > > > > I still see "RPC: Could not send backchannel reply error: -110" > > quite often, along with slow-running tests. Debugging shows that the > > backchannel is still stumbling when it has to queue a callback reply > > on a busy transport. > > > > Note that every one of these timeouts causes a connection loss by > > virtue of the xprt_conditional_disconnect() call in that arm of > > call_cb_transmit_status(). > > > > I found that setting to_maxval is necessary to get the RPC timeout > > logic to behave whenever to_exponential is not set. > > > > Fixes: 57331a59ac0d ("NFSv4.1: Use the nfs_client's rpc timeouts for backchannel") > > Signed-off-by: Chuck Lever <chuck.lever@oracle.com> > > That makes sense - I guess we were getting some random stack value in there? Hi Ben- On my systems it was always zero (which is why v1 of this patch did not clear the other fields in @timeout before using it). A zero to_maxval value results in the same timeout-on-sleep behavior as you saw before 57331a59ac0d was applied. A random non-zero value will behave correctly as long as the transport is making forward progress, so we never noticed a problem. > Reviewed-by: Benjamin Coddington <bcodding@redhat.com> > > Ben > > > --- > > net/sunrpc/svc.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c > > index 965a27806bfd..e03f14024e47 100644 > > --- a/net/sunrpc/svc.c > > +++ b/net/sunrpc/svc.c > > @@ -1588,9 +1588,11 @@ void svc_process(struct svc_rqst *rqstp) > > */ > > void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp) > > { > > + struct rpc_timeout timeout = { > > + .to_increment = 0, > > + }; > > struct rpc_task *task; > > int proc_error; > > - struct rpc_timeout timeout; > > > > /* Build the svc_rqst used by the common processing routine */ > > rqstp->rq_xid = req->rq_xid; > > @@ -1643,6 +1645,7 @@ void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp) > > timeout.to_initval = req->rq_xprt->timeout->to_initval; > > timeout.to_retries = req->rq_xprt->timeout->to_retries; > > } > > + timeout.to_maxval = timeout.to_initval; > > memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf)); > > task = rpc_run_bc_task(req, &timeout); > > > > -- > > 2.45.1 >
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 965a27806bfd..e03f14024e47 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1588,9 +1588,11 @@ void svc_process(struct svc_rqst *rqstp) */ void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp) { + struct rpc_timeout timeout = { + .to_increment = 0, + }; struct rpc_task *task; int proc_error; - struct rpc_timeout timeout; /* Build the svc_rqst used by the common processing routine */ rqstp->rq_xid = req->rq_xid; @@ -1643,6 +1645,7 @@ void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp) timeout.to_initval = req->rq_xprt->timeout->to_initval; timeout.to_retries = req->rq_xprt->timeout->to_retries; } + timeout.to_maxval = timeout.to_initval; memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf)); task = rpc_run_bc_task(req, &timeout);