Patch "SUNRPC: Fix backchannel reply, again" has been added to the 6.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    SUNRPC: Fix backchannel reply, again

to the 6.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sunrpc-fix-backchannel-reply-again.patch
and it can be found in the queue-6.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit eead2c9784c7d6d39f38f64035e3624c95aa0d34
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Wed Jun 19 09:51:08 2024 -0400

    SUNRPC: Fix backchannel reply, again
    
    [ Upstream commit 6ddc9deacc1312762c2edd9de00ce76b00f69f7c ]
    
    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@xxxxxxxxxx>
    Reviewed-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
    Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 2b4b1276d4e86..d9cda1e53a017 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1557,9 +1557,11 @@ 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;
@@ -1612,6 +1614,7 @@ 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);