On Fri, 04 Jul 2025, Jeff Layton wrote:
> The server-side sunrpc code currently calls pc_release before sending
> the reply. A later nfsd patch will change some pc_release callbacks to
> do extra work to clean the pagecache. There is no need to delay sending
> the reply for this, however.
>
> Change svc_process and svc_process_bc to call pc_release after sending
> the reply instead of before.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> net/sunrpc/svc.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index b1fab3a6954437cf751e4725fa52cfc83eddf2ab..103bb6ba8e140fdccd6cab124e715caeb41bb445 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -1426,8 +1426,6 @@ svc_process_common(struct svc_rqst *rqstp)
>
> /* Call the function that processes the request. */
> rc = process.dispatch(rqstp);
> - if (procp->pc_release)
> - procp->pc_release(rqstp);
> xdr_finish_decode(xdr);
>
> if (!rc)
> @@ -1526,6 +1524,14 @@ static void svc_drop(struct svc_rqst *rqstp)
> trace_svc_drop(rqstp);
> }
>
> +static void svc_release_rqst(struct svc_rqst *rqstp)
> +{
> + const struct svc_procedure *procp = rqstp->rq_procinfo;
> +
> + if (procp && procp->pc_release)
> + procp->pc_release(rqstp);
> +}
> +
> /**
> * svc_process - Execute one RPC transaction
> * @rqstp: RPC transaction context
> @@ -1533,7 +1539,7 @@ static void svc_drop(struct svc_rqst *rqstp)
> */
> void svc_process(struct svc_rqst *rqstp)
> {
> - struct kvec *resv = &rqstp->rq_res.head[0];
> + struct kvec *resv = &rqstp->rq_res.head[0];
Commas and Tabs - you can never really have enough of them, can you?
> __be32 *p;
>
> #if IS_ENABLED(CONFIG_FAIL_SUNRPC)
> @@ -1565,9 +1571,12 @@ void svc_process(struct svc_rqst *rqstp)
> if (unlikely(*p != rpc_call))
> goto out_baddir;
>
> - if (!svc_process_common(rqstp))
> + if (!svc_process_common(rqstp)) {
> + svc_release_rqst(rqstp);
> goto out_drop;
> + }
> svc_send(rqstp);
> + svc_release_rqst(rqstp);
> return;
Should we, as a general rule, avoid calling any cleanup function more
than once? When tempted, we DEFINE_FREE() a cleanup function and
declare the variable appropriately.
Though in this case it might be easier to:
if (svc_process_common(rqstp))
svc_send(rqstp);
else
svc_drop(rqstp);
svc_rlease_rqst(rqstp);
return;
svc_process_bc() is a little more awkward.
But in general, delaying the release function until after the send seems
sound, and this patches appears to do it corretly.
Reviewed-by: NeilBrown <neil@xxxxxxxxxx>
NeilBrown
