linux-kernel - Re: [PATCH 1/2] nfsd/sunrpc: add svc_rqst->rq_private pointer and remove rq_lease

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Message-Id: <5806015a-ad18-4bc9-a320-2fdab4d86969@app.fastmail.com>
Date: Tue, 13 Jan 2026 14:21:06 -0500
From: "Chuck Lever" <cel@...nel.org>
To: "Jeff Layton" <jlayton@...nel.org>,
 "Chuck Lever" <chuck.lever@...cle.com>, NeilBrown <neil@...wn.name>,
 "Olga Kornievskaia" <okorniev@...hat.com>, "Dai Ngo" <Dai.Ngo@...cle.com>,
 "Tom Talpey" <tom@...pey.com>, "Trond Myklebust" <trondmy@...nel.org>,
 "Anna Schumaker" <anna@...nel.org>
Cc: "Benjamin Coddington" <bcodding@...merspace.com>,
 linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] nfsd/sunrpc: add svc_rqst->rq_private pointer and remove
 rq_lease_breaker

On Tue, Jan 13, 2026, at 1:37 PM, Jeff Layton wrote:
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index eee8c3f4a251a3fae6e41679de0ec34c76caf198..8ce366c9e49220e8baf475c2e5f3424fedc1cec1 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -900,6 +900,7 @@ nfsd(void *vrqstp)
> struct svc_xprt *perm_sock = list_entry(rqstp->rq_server->sv_permsocks.next, typeof(struct svc_xprt), xpt_list);
> struct net *net = perm_sock->xpt_net;
> struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> + struct nfsd_thread_local_info ntli = { };
> bool have_mutex = false;
>  
> /* At this point, the thread shares current->fs
> @@ -914,6 +915,8 @@ nfsd(void *vrqstp)
>  
> set_freezable();
>  
> + rqstp->rq_private = &ntli;
> +
> /*
> * The main request loop
> */

Thanks for tackling this one. Nits below...

This assumes sizeof(structure nfsd_thread_local_info) will always
be small enough that it is reasonable to keep on the stack. I
can't say that would be a good bet in the long run.

And we don't need the perfect reliability of not doing a dynamic
allocation here. If kmalloc(sizeof(struct nfsd_thread_local_info))
fails, the thread exits immediately, no harm.

Also, scatter-gather lists could not be stored directly in this
object because it is on the stack. If Ben wanted to stick a
32-byte buffer in struct nfsd_thread_local_info to be used with
the crypto API, it would have to be a pointer to it, not the
buffer itself.

Chuck Lever