lockd: hold a reference to nlmsvc_serv while stopping the thread.

Both nfsd and nfsv4-callback take a temporary reference to the svc_serv
while calling svc_set_num_threads() to stop the last thread.  lockd does
not.

This extra reference prevents the scv_serv from being freed when the
last thread drops its reference count.  This is not currently needed
for lockd as the svc_serv is not accessed after the last thread is told
to exit.

However a future patch will require svc_exit_thread() to access the
svc_serv after the svc_put() so it will need the code that calls
svc_set_num_threads() to keep a reference and keep the svc_serv active.

So copy the pattern from nfsd and nfsv4-cb to lockd, and take a
reference around svc_set_num_threads(.., 0)

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
NeilBrown 2023-10-11 09:31:22 +11:00 committed by Chuck Lever
parent 063ab935a4
commit f4578ba11c

View File

@ -373,7 +373,9 @@ static void lockd_put(void)
unregister_inet6addr_notifier(&lockd_inet6addr_notifier);
#endif
svc_get(nlmsvc_serv);
svc_set_num_threads(nlmsvc_serv, NULL, 0);
svc_put(nlmsvc_serv);
timer_delete_sync(&nlmsvc_retry);
nlmsvc_serv = NULL;
dprintk("lockd_down: service destroyed\n");