On Fri, 2024-07-26 at 13:59 +1000, NeilBrown wrote:
>
> The locking required for svc_exit_thread() is not obvious, so document
> it in a kdoc comment.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
>
> Rather than repost patch 5/14 of my recent set for dynamic thread
> management, I decided to provide this as an independent patch which
> could usefully be inserted into the series before 5/14. That will make
> that patch easier to understand/review.
>
> NeilBrown
>
>
> net/sunrpc/svc.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
> index 26b6e73fc0de..4c3df893c532 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -955,6 +955,20 @@ void svc_rqst_release_pages(struct svc_rqst *rqstp)
> }
> }
>
> +/**
> + * svc_exit_thread - finalise the termination of a sunrpc server thread
> + * @rqstp: the svc_rqst which represents the thread.
> + *
> + * When a thread started with svc_new_thread() exits it must call
> + * svc_exit_thread() as its last act. This must be done with the
> + * service mutex held. Normally this is held by a DIFFERENT thread, the
> + * one that is calling svc_set_num_threads() and which will wait for
> + * SP_VICTIM_REMAINS to be cleared before dropping the mutex. If the
> + * thread exits for any reason other than svc_thread_should_stop()
> + * returning %true (which indicated that svc_set_num_threads() is
> + * waiting for it to exit), then it must take the service mutex itself,
> + * which can only safely be done using mutex_try_lock().
> + */
> void
> svc_exit_thread(struct svc_rqst *rqstp)
> {
Nice to have this clearly stated.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
