nfsd: separate nfsd_last_thread() from nfsd_put()

Now that the last nfsd thread is stopped by an explicit act of calling
svc_set_num_threads() with a count of zero, we only have a limited
number of places that can happen, and don't need to call
nfsd_last_thread() in nfsd_put()

So separate that out and call it at the two places where the number of
threads is set to zero.

Move the clearing of ->nfsd_serv and the call to svc_xprt_destroy_all()
into nfsd_last_thread(), as they are really part of the same action.

nfsd_put() is now a thin wrapper around svc_put(), so make it a static
inline.

nfsd_put() cannot be called after nfsd_last_thread(), so in a couple of
places we have to use svc_put() instead.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index d88498f8b275cf4f7e5fb44c01741a4e7163606e..11c14faa6c67be6e5229cffb3f7e1e2da811eff2 100644 (file)
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -96,7 +96,12 @@ int          nfsd_pool_stats_open(struct inode *, struct file *);
 int            nfsd_pool_stats_release(struct inode *, struct file *);
 void           nfsd_shutdown_threads(struct net *net);
 
-void           nfsd_put(struct net *net);
+static inline void nfsd_put(struct net *net)
+{
+       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+       svc_put(nn->nfsd_serv);
+}
 
 bool           i_am_nfsd(void);
 

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 56a776cd4e2d5f432b2d9f1c15522cf5fd1a5307..a0b16e3dd91ac476a50e5768a5c819924f442cd7 100644 (file)
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -542,9 +542,14 @@ static struct notifier_block nfsd_inet6addr_notifier = {
 /* Only used under nfsd_mutex, so this atomic may be overkill: */
 static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
 
-static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
+static void nfsd_last_thread(struct net *net)
 {
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+       struct svc_serv *serv = nn->nfsd_serv;
+
+       spin_lock(&nfsd_notifier_lock);
+       nn->nfsd_serv = NULL;
+       spin_unlock(&nfsd_notifier_lock);
 
        /* check if the notifier still has clients */
        if (atomic_dec_return(&nfsd_notifier_refcount) == 0) {
@@ -554,6 +559,8 @@ static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
 #endif
        }
 
+       svc_xprt_destroy_all(serv, net);
+
        /*
         * write_ports can create the server without actually starting
         * any threads--if we get shut down before any threads are
@@ -644,7 +651,8 @@ void nfsd_shutdown_threads(struct net *net)
        svc_get(serv);
        /* Kill outstanding nfsd threads */
        svc_set_num_threads(serv, NULL, 0);
-       nfsd_put(net);
+       nfsd_last_thread(net);
+       svc_put(serv);
        mutex_unlock(&nfsd_mutex);
 }
 
@@ -674,9 +682,6 @@ int nfsd_create_serv(struct net *net)
        serv->sv_maxconn = nn->max_connections;
        error = svc_bind(serv, net);
        if (error < 0) {
-               /* NOT nfsd_put() as notifiers (see below) haven't
-                * been set up yet.
-                */
                svc_put(serv);
                return error;
        }
@@ -719,29 +724,6 @@ int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
        return 0;
 }
 
-/* This is the callback for kref_put() below.
- * There is no code here as the first thing to be done is
- * call svc_shutdown_net(), but we cannot get the 'net' from
- * the kref.  So do all the work when kref_put returns true.
- */
-static void nfsd_noop(struct kref *ref)
-{
-}
-
-void nfsd_put(struct net *net)
-{
-       struct nfsd_net *nn = net_generic(net, nfsd_net_id);
-
-       if (kref_put(&nn->nfsd_serv->sv_refcnt, nfsd_noop)) {
-               svc_xprt_destroy_all(nn->nfsd_serv, net);
-               nfsd_last_thread(nn->nfsd_serv, net);
-               svc_destroy(&nn->nfsd_serv->sv_refcnt);
-               spin_lock(&nfsd_notifier_lock);
-               nn->nfsd_serv = NULL;
-               spin_unlock(&nfsd_notifier_lock);
-       }
-}
-
 int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 {
        int i = 0;
@@ -792,7 +774,7 @@ int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
                if (err)
                        break;
        }
-       nfsd_put(net);
+       svc_put(nn->nfsd_serv);
        return err;
 }
 
@@ -807,6 +789,7 @@ nfsd_svc(int nrservs, struct net *net, const struct cred *cred)
        int     error;
        bool    nfsd_up_before;
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+       struct svc_serv *serv;
 
        mutex_lock(&nfsd_mutex);
        dprintk("nfsd: creating service\n");
@@ -826,22 +809,25 @@ nfsd_svc(int nrservs, struct net *net, const struct cred *cred)
                goto out;
 
        nfsd_up_before = nn->nfsd_net_up;
+       serv = nn->nfsd_serv;
 
        error = nfsd_startup_net(net, cred);
        if (error)
                goto out_put;
-       error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
+       error = svc_set_num_threads(serv, NULL, nrservs);
        if (error)
                goto out_shutdown;
-       error = nn->nfsd_serv->sv_nrthreads;
+       error = serv->sv_nrthreads;
+       if (error == 0)
+               nfsd_last_thread(net);
 out_shutdown:
        if (error < 0 && !nfsd_up_before)
                nfsd_shutdown_net(net);
 out_put:
        /* Threads now hold service active */
        if (xchg(&nn->keep_active, 0))
-               nfsd_put(net);
-       nfsd_put(net);
+               svc_put(serv);
+       svc_put(serv);
 out:
        mutex_unlock(&nfsd_mutex);
        return error;