On Mon, 2023-10-30 at 12:08 +1100, NeilBrown wrote:
> Rather than using svc_get() and svc_put() to hold a stable reference to
> the nfsd_svc for netlink lookups, simply hold the mutex for the entire
> time.
>
> The "entire" time isn't very long, and the mutex is not often contented.
>
> This makes way for use to remove the refcounts of svc, which is more
> confusing than useful.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/nfsd/nfsctl.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index d78ae4452946..8f644f1d157c 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1515,11 +1515,10 @@ int nfsd_nl_rpc_status_get_start(struct netlink_callback *cb)
> int ret = -ENODEV;
>
> mutex_lock(&nfsd_mutex);
> - if (nn->nfsd_serv) {
> - svc_get(nn->nfsd_serv);
> + if (nn->nfsd_serv)
> ret = 0;
> - }
> - mutex_unlock(&nfsd_mutex);
> + else
> + mutex_unlock(&nfsd_mutex);
>
> return ret;
> }
> @@ -1691,8 +1690,6 @@ int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
> */
> int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
> {
> - mutex_lock(&nfsd_mutex);
> - nfsd_put(sock_net(cb->skb->sk));
> mutex_unlock(&nfsd_mutex);
>
> return 0;
(cc'ing Lorenzo since he wrote this)
I think Lorenzo did it this way originally, and I convinced him to take
a reference instead. This should be fine though.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
