SUNRPC: Remove the server 'authtab_lock' and just use RCU (30382d6c) · Commits · 戴 / test

net/sunrpc/svcauth.c

+34 −18

Original line number	Diff line number	Diff line
		@@ -27,12 +27,32 @@
		extern struct auth_ops svcauth_null;
		extern struct auth_ops svcauth_unix;

		static DEFINE_SPINLOCK(authtab_lock);
		static struct auth_ops *authtab[RPC_AUTH_MAXFLAVOR] = {
		[0] = &svcauth_null,
		[1] = &svcauth_unix,
		static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = {
		[RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null,
		[RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix,
		};

		static struct auth_ops *
		svc_get_auth_ops(rpc_authflavor_t flavor)
		{
		struct auth_ops *aops;

		if (flavor >= RPC_AUTH_MAXFLAVOR)
		return NULL;
		rcu_read_lock();
		aops = rcu_dereference(authtab[flavor]);
		if (aops != NULL && !try_module_get(aops->owner))
		aops = NULL;
		rcu_read_unlock();
		return aops;
		}

		static void
		svc_put_auth_ops(struct auth_ops *aops)
		{
		module_put(aops->owner);
		}

		int
		svc_authenticate(struct svc_rqst rqstp, __be32 authp)
		{
		@@ -45,14 +65,11 @@ svc_authenticate(struct svc_rqst rqstp, __be32 authp)

		dprintk("svc: svc_authenticate (%d)\n", flavor);

		spin_lock(&authtab_lock);
		if (flavor >= RPC_AUTH_MAXFLAVOR \|\| !(aops = authtab[flavor]) \|\|
		!try_module_get(aops->owner)) {
		spin_unlock(&authtab_lock);
		aops = svc_get_auth_ops(flavor);
		if (aops == NULL) {
		*authp = rpc_autherr_badcred;
		return SVC_DENIED;
		}
		spin_unlock(&authtab_lock);

		rqstp->rq_auth_slack = 0;
		init_svc_cred(&rqstp->rq_cred);
		@@ -82,7 +99,7 @@ int svc_authorise(struct svc_rqst *rqstp)

		if (aops) {
		rv = aops->release(rqstp);
		module_put(aops->owner);
		svc_put_auth_ops(aops);
		}
		return rv;
		}
		@@ -90,13 +107,14 @@ int svc_authorise(struct svc_rqst *rqstp)
		int
		svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
		{
		struct auth_ops *old;
		int rv = -EINVAL;
		spin_lock(&authtab_lock);
		if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
		authtab[flavor] = aops;

		if (flavor < RPC_AUTH_MAXFLAVOR) {
		old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops);
		if (old == NULL \|\| old == aops)
		rv = 0;
		}
		spin_unlock(&authtab_lock);
		return rv;
		}
		EXPORT_SYMBOL_GPL(svc_auth_register);
		@@ -104,10 +122,8 @@ EXPORT_SYMBOL_GPL(svc_auth_register);
		void
		svc_auth_unregister(rpc_authflavor_t flavor)
		{
		spin_lock(&authtab_lock);
		if (flavor < RPC_AUTH_MAXFLAVOR)
		authtab[flavor] = NULL;
		spin_unlock(&authtab_lock);
		rcu_assign_pointer(authtab[flavor], NULL);
		}
		EXPORT_SYMBOL_GPL(svc_auth_unregister);

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