6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: NeilBrown <neilb@xxxxxxx>
[ Upstream commit 9f28a971ee9fdf1bf8ce8c88b103f483be610277 ]
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@xxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Stable-dep-of: 2a501f55cd64 ("nfsd: call nfsd_last_thread() before final nfsd_put()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/nfsd/nfsd.h | 7 ++++++-
fs/nfsd/nfssvc.c | 52 ++++++++++++++++++------------------------------
2 files changed, 25 insertions(+), 34 deletions(-)
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 09726c5b9a317..fddd70372e4cb 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -97,7 +97,12 @@ 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 f6cc99af81925..6ac18399fed2b 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -523,9 +523,14 @@ 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) {
@@ -535,6 +540,8 @@ 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
@@ -625,7 +632,8 @@ 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);
}
@@ -655,9 +663,6 @@ 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;
}
@@ -700,29 +705,6 @@ 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;
@@ -773,7 +755,7 @@ int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
if (err)
break;
}
- nfsd_put(net);
+ svc_put(nn->nfsd_serv);
return err;
}
@@ -788,6 +770,7 @@ 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");
@@ -807,22 +790,25 @@ 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;
--
2.43.0
