nfsd: make nfsd_stats.th_cnt atomic_t
This allows us to move the updates for th_cnt out of the mutex.
This is a step towards reducing mutex coverage in nfsd().
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 5f605e7..fc58995 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -57,7 +57,7 @@ static __be32 nfsd_init_request(struct svc_rqst *,
/*
* nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members
* of the svc_serv struct. In particular, ->sv_nrthreads but also to some
- * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
+ * extent ->sv_temp_socks and ->sv_permsocks.
*
* If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a
* properly initialised 'struct svc_serv' with ->sv_nrthreads > 0 (unless
@@ -955,8 +955,8 @@ nfsd(void *vrqstp)
allow_signal(SIGINT);
allow_signal(SIGQUIT);
- nfsdstats.th_cnt++;
mutex_unlock(&nfsd_mutex);
+ atomic_inc(&nfsdstats.th_cnt);
set_freezable();
@@ -983,8 +983,8 @@ nfsd(void *vrqstp)
/* Clear signals before calling svc_exit_thread() */
flush_signals(current);
+ atomic_dec(&nfsdstats.th_cnt);
mutex_lock(&nfsd_mutex);
- nfsdstats.th_cnt --;
out:
/* Take an extra ref so that the svc_put in svc_exit_thread()