1 files changed, 383 insertions, 300 deletions

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index ed2fdd210c0b..5a827afd8e3b 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/net/sunrpc/auth.c
  *
@@ -8,6 +9,7 @@
 
 #include <linux/types.h>
 #include <linux/sched.h>
+#include <linux/cred.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/errno.h>
@@ -16,9 +18,7 @@
 #include <linux/sunrpc/gss_api.h>
 #include <linux/spinlock.h>
 
-#ifdef RPC_DEBUG
-# define RPCDBG_FACILITY	RPCDBG_AUTH
-#endif
+#include <trace/events/sunrpc.h>
 
 #define RPC_CREDCACHE_DEFAULT_HASHBITS	(4)
 struct rpc_cred_cache {
@@ -29,16 +29,29 @@ struct rpc_cred_cache {
 
 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
 
-static DEFINE_SPINLOCK(rpc_authflavor_lock);
-static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
-	&authnull_ops,		/* AUTH_NULL */
-	&authunix_ops,		/* AUTH_UNIX */
-	NULL,			/* others can be loadable modules */
+static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
+	[RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
+	[RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
+	[RPC_AUTH_TLS]  = (const struct rpc_authops __force __rcu *)&authtls_ops,
 };
 
 static LIST_HEAD(cred_unused);
 static unsigned long number_cred_unused;
 
+static struct cred machine_cred = {
+	.usage = ATOMIC_INIT(1),
+};
+
+/*
+ * Return the machine_cred pointer to be used whenever
+ * the a generic machine credential is needed.
+ */
+const struct cred *rpc_machine_cred(void)
+{
+	return &machine_cred;
+}
+EXPORT_SYMBOL_GPL(rpc_machine_cred);
+
 #define MAX_HASHTABLE_BITS (14)
 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
 {
@@ -48,12 +61,10 @@ static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
 
 	if (!val)
 		goto out_inval;
-	ret = strict_strtoul(val, 0, &num);
-	if (ret == -EINVAL)
+	ret = kstrtoul(val, 0, &num);
+	if (ret)
 		goto out_inval;
-	nbits = fls(num);
-	if (num > (1U << nbits))
-		nbits++;
+	nbits = fls(num - 1);
 	if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
 		goto out_inval;
 	*(unsigned int *)kp->arg = nbits;
@@ -67,12 +78,12 @@ static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
 	unsigned int nbits;
 
 	nbits = *(unsigned int *)kp->arg;
-	return sprintf(buffer, "%u", 1U << nbits);
+	return sprintf(buffer, "%u\n", 1U << nbits);
 }
 
 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
 
-static struct kernel_param_ops param_ops_hashtbl_sz = {
+static const struct kernel_param_ops param_ops_hashtbl_sz = {
 	.set = param_set_hashtbl_sz,
 	.get = param_get_hashtbl_sz,
 };
@@ -80,6 +91,10 @@ static struct kernel_param_ops param_ops_hashtbl_sz = {
 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
 
+static unsigned long auth_max_cred_cachesize = ULONG_MAX;
+module_param(auth_max_cred_cachesize, ulong, 0644);
+MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
+
 static u32
 pseudoflavor_to_flavor(u32 flavor) {
 	if (flavor > RPC_AUTH_MAXFLAVOR)
@@ -90,39 +105,65 @@ pseudoflavor_to_flavor(u32 flavor) {
 int
 rpcauth_register(const struct rpc_authops *ops)
 {
+	const struct rpc_authops *old;
 	rpc_authflavor_t flavor;
-	int ret = -EPERM;
 
 	if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 		return -EINVAL;
-	spin_lock(&rpc_authflavor_lock);
-	if (auth_flavors[flavor] == NULL) {
-		auth_flavors[flavor] = ops;
-		ret = 0;
-	}
-	spin_unlock(&rpc_authflavor_lock);
-	return ret;
+	old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
+	if (old == NULL || old == ops)
+		return 0;
+	return -EPERM;
 }
 EXPORT_SYMBOL_GPL(rpcauth_register);
 
 int
 rpcauth_unregister(const struct rpc_authops *ops)
 {
+	const struct rpc_authops *old;
 	rpc_authflavor_t flavor;
-	int ret = -EPERM;
 
 	if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 		return -EINVAL;
-	spin_lock(&rpc_authflavor_lock);
-	if (auth_flavors[flavor] == ops) {
-		auth_flavors[flavor] = NULL;
-		ret = 0;
-	}
-	spin_unlock(&rpc_authflavor_lock);
-	return ret;
+
+	old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
+	if (old == ops || old == NULL)
+		return 0;
+	return -EPERM;
 }
 EXPORT_SYMBOL_GPL(rpcauth_unregister);
 
+static const struct rpc_authops *
+rpcauth_get_authops(rpc_authflavor_t flavor)
+{
+	const struct rpc_authops *ops;
+
+	if (flavor >= RPC_AUTH_MAXFLAVOR)
+		return NULL;
+
+	rcu_read_lock();
+	ops = rcu_dereference(auth_flavors[flavor]);
+	if (ops == NULL) {
+		rcu_read_unlock();
+		request_module("rpc-auth-%u", flavor);
+		rcu_read_lock();
+		ops = rcu_dereference(auth_flavors[flavor]);
+		if (ops == NULL)
+			goto out;
+	}
+	if (!try_module_get(ops->owner))
+		ops = NULL;
+out:
+	rcu_read_unlock();
+	return ops;
+}
+
+static void
+rpcauth_put_authops(const struct rpc_authops *ops)
+{
+	module_put(ops->owner);
+}
+
 /**
  * rpcauth_get_pseudoflavor - check if security flavor is supported
  * @flavor: a security flavor
@@ -135,25 +176,16 @@ EXPORT_SYMBOL_GPL(rpcauth_unregister);
 rpc_authflavor_t
 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
 {
-	const struct rpc_authops *ops;
+	const struct rpc_authops *ops = rpcauth_get_authops(flavor);
 	rpc_authflavor_t pseudoflavor;
 
-	ops = auth_flavors[flavor];
-	if (ops == NULL)
-		request_module("rpc-auth-%u", flavor);
-	spin_lock(&rpc_authflavor_lock);
-	ops = auth_flavors[flavor];
-	if (ops == NULL || !try_module_get(ops->owner)) {
-		spin_unlock(&rpc_authflavor_lock);
+	if (!ops)
 		return RPC_AUTH_MAXFLAVOR;
-	}
-	spin_unlock(&rpc_authflavor_lock);
-
 	pseudoflavor = flavor;
 	if (ops->info2flavor != NULL)
 		pseudoflavor = ops->info2flavor(info);
 
-	module_put(ops->owner);
+	rpcauth_put_authops(ops);
 	return pseudoflavor;
 }
 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
@@ -173,104 +205,33 @@ rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
 	const struct rpc_authops *ops;
 	int result;
 
-	if (flavor >= RPC_AUTH_MAXFLAVOR)
-		return -EINVAL;
-
-	ops = auth_flavors[flavor];
+	ops = rpcauth_get_authops(flavor);
 	if (ops == NULL)
-		request_module("rpc-auth-%u", flavor);
-	spin_lock(&rpc_authflavor_lock);
-	ops = auth_flavors[flavor];
-	if (ops == NULL || !try_module_get(ops->owner)) {
-		spin_unlock(&rpc_authflavor_lock);
 		return -ENOENT;
-	}
-	spin_unlock(&rpc_authflavor_lock);
 
 	result = -ENOENT;
 	if (ops->flavor2info != NULL)
 		result = ops->flavor2info(pseudoflavor, info);
 
-	module_put(ops->owner);
+	rpcauth_put_authops(ops);
 	return result;
 }
 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
 
-/**
- * rpcauth_list_flavors - discover registered flavors and pseudoflavors
- * @array: array to fill in
- * @size: size of "array"
- *
- * Returns the number of array items filled in, or a negative errno.
- *
- * The returned array is not sorted by any policy.  Callers should not
- * rely on the order of the items in the returned array.
- */
-int
-rpcauth_list_flavors(rpc_authflavor_t *array, int size)
-{
-	rpc_authflavor_t flavor;
-	int result = 0;
-
-	spin_lock(&rpc_authflavor_lock);
-	for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
-		const struct rpc_authops *ops = auth_flavors[flavor];
-		rpc_authflavor_t pseudos[4];
-		int i, len;
-
-		if (result >= size) {
-			result = -ENOMEM;
-			break;
-		}
-
-		if (ops == NULL)
-			continue;
-		if (ops->list_pseudoflavors == NULL) {
-			array[result++] = ops->au_flavor;
-			continue;
-		}
-		len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
-		if (len < 0) {
-			result = len;
-			break;
-		}
-		for (i = 0; i < len; i++) {
-			if (result >= size) {
-				result = -ENOMEM;
-				break;
-			}
-			array[result++] = pseudos[i];
-		}
-	}
-	spin_unlock(&rpc_authflavor_lock);
-
-	dprintk("RPC:       %s returns %d\n", __func__, result);
-	return result;
-}
-EXPORT_SYMBOL_GPL(rpcauth_list_flavors);
-
 struct rpc_auth *
-rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
+rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 {
-	struct rpc_auth		*auth;
+	struct rpc_auth	*auth = ERR_PTR(-EINVAL);
 	const struct rpc_authops *ops;
-	u32			flavor = pseudoflavor_to_flavor(pseudoflavor);
+	u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
 
-	auth = ERR_PTR(-EINVAL);
-	if (flavor >= RPC_AUTH_MAXFLAVOR)
+	ops = rpcauth_get_authops(flavor);
+	if (ops == NULL)
 		goto out;
 
-	if ((ops = auth_flavors[flavor]) == NULL)
-		request_module("rpc-auth-%u", flavor);
-	spin_lock(&rpc_authflavor_lock);
-	ops = auth_flavors[flavor];
-	if (ops == NULL || !try_module_get(ops->owner)) {
-		spin_unlock(&rpc_authflavor_lock);
-		goto out;
-	}
-	spin_unlock(&rpc_authflavor_lock);
-	auth = ops->create(clnt, pseudoflavor);
-	module_put(ops->owner);
+	auth = ops->create(args, clnt);
+
+	rpcauth_put_authops(ops);
 	if (IS_ERR(auth))
 		return auth;
 	if (clnt->cl_auth)
@@ -285,32 +246,37 @@ EXPORT_SYMBOL_GPL(rpcauth_create);
 void
 rpcauth_release(struct rpc_auth *auth)
 {
-	if (!atomic_dec_and_test(&auth->au_count))
+	if (!refcount_dec_and_test(&auth->au_count))
 		return;
 	auth->au_ops->destroy(auth);
 }
 
 static DEFINE_SPINLOCK(rpc_credcache_lock);
 
-static void
+/*
+ * On success, the caller is responsible for freeing the reference
+ * held by the hashtable
+ */
+static bool
 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 {
+	if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
+		return false;
 	hlist_del_rcu(&cred->cr_hash);
-	smp_mb__before_clear_bit();
-	clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
+	return true;
 }
 
-static int
+static bool
 rpcauth_unhash_cred(struct rpc_cred *cred)
 {
 	spinlock_t *cache_lock;
-	int ret;
+	bool ret;
 
+	if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
+		return false;
 	cache_lock = &cred->cr_auth->au_credcache->lock;
 	spin_lock(cache_lock);
-	ret = atomic_read(&cred->cr_count) == 0;
-	if (ret)
-		rpcauth_unhash_cred_locked(cred);
+	ret = rpcauth_unhash_cred_locked(cred);
 	spin_unlock(cache_lock);
 	return ret;
 }
@@ -342,6 +308,15 @@ out_nocache:
 }
 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 
+char *
+rpcauth_stringify_acceptor(struct rpc_cred *cred)
+{
+	if (!cred->cr_ops->crstringify_acceptor)
+		return NULL;
+	return cred->cr_ops->crstringify_acceptor(cred);
+}
+EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
+
 /*
  * Destroy a list of credentials
  */
@@ -357,6 +332,44 @@ void rpcauth_destroy_credlist(struct list_head *head)
 	}
 }
 
+static void
+rpcauth_lru_add_locked(struct rpc_cred *cred)
+{
+	if (!list_empty(&cred->cr_lru))
+		return;
+	number_cred_unused++;
+	list_add_tail(&cred->cr_lru, &cred_unused);
+}
+
+static void
+rpcauth_lru_add(struct rpc_cred *cred)
+{
+	if (!list_empty(&cred->cr_lru))
+		return;
+	spin_lock(&rpc_credcache_lock);
+	rpcauth_lru_add_locked(cred);
+	spin_unlock(&rpc_credcache_lock);
+}
+
+static void
+rpcauth_lru_remove_locked(struct rpc_cred *cred)
+{
+	if (list_empty(&cred->cr_lru))
+		return;
+	number_cred_unused--;
+	list_del_init(&cred->cr_lru);
+}
+
+static void
+rpcauth_lru_remove(struct rpc_cred *cred)
+{
+	if (list_empty(&cred->cr_lru))
+		return;
+	spin_lock(&rpc_credcache_lock);
+	rpcauth_lru_remove_locked(cred);
+	spin_unlock(&rpc_credcache_lock);
+}
+
 /*
  * Clear the RPC credential cache, and delete those credentials
  * that are not referenced.
@@ -376,13 +389,10 @@ rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 		head = &cache->hashtable[i];
 		while (!hlist_empty(head)) {
 			cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
-			get_rpccred(cred);
-			if (!list_empty(&cred->cr_lru)) {
-				list_del(&cred->cr_lru);
-				number_cred_unused--;
-			}
-			list_add_tail(&cred->cr_lru, &free);
 			rpcauth_unhash_cred_locked(cred);
+			/* Note: We now hold a reference to cred */
+			rpcauth_lru_remove_locked(cred);
+			list_add_tail(&cred->cr_lru, &free);
 		}
 	}
 	spin_unlock(&cache->lock);
@@ -413,62 +423,88 @@ EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 /*
  * Remove stale credentials. Avoid sleeping inside the loop.
  */
-static int
+static long
 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 {
-	spinlock_t *cache_lock;
 	struct rpc_cred *cred, *next;
 	unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
+	long freed = 0;
 
 	list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
 
 		if (nr_to_scan-- == 0)
 			break;
+		if (refcount_read(&cred->cr_count) > 1) {
+			rpcauth_lru_remove_locked(cred);
+			continue;
+		}
 		/*
 		 * Enforce a 60 second garbage collection moratorium
 		 * Note that the cred_unused list must be time-ordered.
 		 */
-		if (time_in_range(cred->cr_expire, expired, jiffies) &&
-		    test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
-			return 0;
-
-		list_del_init(&cred->cr_lru);
-		number_cred_unused--;
-		if (atomic_read(&cred->cr_count) != 0)
+		if (time_in_range(cred->cr_expire, expired, jiffies))
+			continue;
+		if (!rpcauth_unhash_cred(cred))
 			continue;
 
-		cache_lock = &cred->cr_auth->au_credcache->lock;
-		spin_lock(cache_lock);
-		if (atomic_read(&cred->cr_count) == 0) {
-			get_rpccred(cred);
-			list_add_tail(&cred->cr_lru, free);
-			rpcauth_unhash_cred_locked(cred);
-		}
-		spin_unlock(cache_lock);
+		rpcauth_lru_remove_locked(cred);
+		freed++;
+		list_add_tail(&cred->cr_lru, free);
 	}
-	return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
+	return freed ? freed : SHRINK_STOP;
 }
 
-/*
- * Run memory cache shrinker.
- */
-static int
-rpcauth_cache_shrinker(struct shrinker *shrink, struct shrink_control *sc)
+static unsigned long
+rpcauth_cache_do_shrink(int nr_to_scan)
 {
 	LIST_HEAD(free);
-	int res;
-	int nr_to_scan = sc->nr_to_scan;
-	gfp_t gfp_mask = sc->gfp_mask;
+	unsigned long freed;
 
-	if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
-		return (nr_to_scan == 0) ? 0 : -1;
-	if (list_empty(&cred_unused))
-		return 0;
 	spin_lock(&rpc_credcache_lock);
-	res = rpcauth_prune_expired(&free, nr_to_scan);
+	freed = rpcauth_prune_expired(&free, nr_to_scan);
 	spin_unlock(&rpc_credcache_lock);
 	rpcauth_destroy_credlist(&free);
-	return res;
+
+	return freed;
+}
+
+/*
+ * Run memory cache shrinker.
+ */
+static unsigned long
+rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
+
+{
+	if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
+		return SHRINK_STOP;
+
+	/* nothing left, don't come back */
+	if (list_empty(&cred_unused))
+		return SHRINK_STOP;
+
+	return rpcauth_cache_do_shrink(sc->nr_to_scan);
+}
+
+static unsigned long
+rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
+
+{
+	return number_cred_unused;
+}
+
+static void
+rpcauth_cache_enforce_limit(void)
+{
+	unsigned long diff;
+	unsigned int nr_to_scan;
+
+	if (number_cred_unused <= auth_max_cred_cachesize)
+		return;
+	diff = number_cred_unused - auth_max_cred_cachesize;
+	nr_to_scan = 100;
+	if (diff < nr_to_scan)
+		nr_to_scan = diff;
+	rpcauth_cache_do_shrink(nr_to_scan);
 }
 
 /*
@@ -476,7 +512,7 @@ rpcauth_cache_shrinker(struct shrinker *shrink, struct shrink_control *sc)
  */
 struct rpc_cred *
 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
-		int flags)
+		int flags, gfp_t gfp)
 {
 	LIST_HEAD(free);
 	struct rpc_cred_cache *cache = auth->au_credcache;
@@ -484,27 +520,22 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 			*entry, *new;
 	unsigned int nr;
 
-	nr = hash_long(from_kuid(&init_user_ns, acred->uid), cache->hashbits);
+	nr = auth->au_ops->hash_cred(acred, cache->hashbits);
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
 		if (!entry->cr_ops->crmatch(acred, entry, flags))
 			continue;
-		spin_lock(&cache->lock);
-		if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
-			spin_unlock(&cache->lock);
-			continue;
-		}
 		cred = get_rpccred(entry);
-		spin_unlock(&cache->lock);
-		break;
+		if (cred)
+			break;
 	}
 	rcu_read_unlock();
 
 	if (cred != NULL)
 		goto found;
 
-	new = auth->au_ops->crcreate(auth, acred, flags);
+	new = auth->au_ops->crcreate(auth, acred, flags, gfp);
 	if (IS_ERR(new)) {
 		cred = new;
 		goto out;
@@ -515,15 +546,18 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 		if (!entry->cr_ops->crmatch(acred, entry, flags))
 			continue;
 		cred = get_rpccred(entry);
-		break;
+		if (cred)
+			break;
 	}
 	if (cred == NULL) {
 		cred = new;
 		set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
+		refcount_inc(&cred->cr_count);
 		hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 	} else
 		list_add_tail(&new->cr_lru, &free);
 	spin_unlock(&cache->lock);
+	rpcauth_cache_enforce_limit();
 found:
 	if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
 	    cred->cr_ops->cr_init != NULL &&
@@ -547,18 +581,12 @@ rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 	struct rpc_cred *ret;
 	const struct cred *cred = current_cred();
 
-	dprintk("RPC:       looking up %s cred\n",
-		auth->au_ops->au_name);
-
 	memset(&acred, 0, sizeof(acred));
-	acred.uid = cred->fsuid;
-	acred.gid = cred->fsgid;
-	acred.group_info = get_group_info(((struct cred *)cred)->group_info);
-
+	acred.cred = cred;
 	ret = auth->au_ops->lookup_cred(auth, &acred, flags);
-	put_group_info(acred.group_info);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 
 void
 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
@@ -566,37 +594,44 @@ rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 {
 	INIT_HLIST_NODE(&cred->cr_hash);
 	INIT_LIST_HEAD(&cred->cr_lru);
-	atomic_set(&cred->cr_count, 1);
+	refcount_set(&cred->cr_count, 1);
 	cred->cr_auth = auth;
+	cred->cr_flags = 0;
 	cred->cr_ops = ops;
 	cred->cr_expire = jiffies;
-#ifdef RPC_DEBUG
-	cred->cr_magic = RPCAUTH_CRED_MAGIC;
-#endif
-	cred->cr_uid = acred->uid;
+	cred->cr_cred = get_cred(acred->cred);
 }
 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 
-struct rpc_cred *
-rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
+static struct rpc_cred *
+rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 {
-	dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
-			cred->cr_auth->au_ops->au_name, cred);
-	return get_rpccred(cred);
+	struct rpc_auth *auth = task->tk_client->cl_auth;
+	struct auth_cred acred = {
+		.cred = get_task_cred(&init_task),
+	};
+	struct rpc_cred *ret;
+
+	if (RPC_IS_ASYNC(task))
+		lookupflags |= RPCAUTH_LOOKUP_ASYNC;
+	ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
+	put_cred(acred.cred);
+	return ret;
 }
-EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
 
 static struct rpc_cred *
-rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
+rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
 {
 	struct rpc_auth *auth = task->tk_client->cl_auth;
 	struct auth_cred acred = {
-		.uid = GLOBAL_ROOT_UID,
-		.gid = GLOBAL_ROOT_GID,
+		.principal = task->tk_client->cl_principal,
+		.cred = init_task.cred,
 	};
 
-	dprintk("RPC: %5u looking up %s cred\n",
-		task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
+	if (!acred.principal)
+		return NULL;
+	if (RPC_IS_ASYNC(task))
+		lookupflags |= RPCAUTH_LOOKUP_ASYNC;
 	return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 }
 
@@ -605,30 +640,42 @@ rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 {
 	struct rpc_auth *auth = task->tk_client->cl_auth;
 
-	dprintk("RPC: %5u looking up %s cred\n",
-		task->tk_pid, auth->au_ops->au_name);
 	return rpcauth_lookupcred(auth, lookupflags);
 }
 
 static int
-rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
+rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
 {
 	struct rpc_rqst *req = task->tk_rqstp;
-	struct rpc_cred *new;
+	struct rpc_cred *new = NULL;
 	int lookupflags = 0;
+	struct rpc_auth *auth = task->tk_client->cl_auth;
+	struct auth_cred acred = {
+		.cred = cred,
+	};
 
 	if (flags & RPC_TASK_ASYNC)
-		lookupflags |= RPCAUTH_LOOKUP_NEW;
-	if (cred != NULL)
-		new = cred->cr_ops->crbind(task, cred, lookupflags);
-	else if (flags & RPC_TASK_ROOTCREDS)
+		lookupflags |= RPCAUTH_LOOKUP_NEW | RPCAUTH_LOOKUP_ASYNC;
+	if (task->tk_op_cred)
+		/* Task must use exactly this rpc_cred */
+		new = get_rpccred(task->tk_op_cred);
+	else if (cred != NULL && cred != &machine_cred)
+		new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
+	else if (cred == &machine_cred)
+		new = rpcauth_bind_machine_cred(task, lookupflags);
+
+	/* If machine cred couldn't be bound, try a root cred */
+	if (new)
+		;
+	else if (cred == &machine_cred)
 		new = rpcauth_bind_root_cred(task, lookupflags);
+	else if (flags & RPC_TASK_NULLCREDS)
+		new = authnull_ops.lookup_cred(NULL, NULL, 0);
 	else
 		new = rpcauth_bind_new_cred(task, lookupflags);
 	if (IS_ERR(new))
 		return PTR_ERR(new);
-	if (req->rq_cred != NULL)
-		put_rpccred(req->rq_cred);
+	put_rpccred(req->rq_cred);
 	req->rq_cred = new;
 	return 0;
 }
@@ -636,108 +683,145 @@ rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
 void
 put_rpccred(struct rpc_cred *cred)
 {
-	/* Fast path for unhashed credentials */
-	if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
-		if (atomic_dec_and_test(&cred->cr_count))
-			cred->cr_ops->crdestroy(cred);
+	if (cred == NULL)
 		return;
+	rcu_read_lock();
+	if (refcount_dec_and_test(&cred->cr_count))
+		goto destroy;
+	if (refcount_read(&cred->cr_count) != 1 ||
+	    !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
+		goto out;
+	if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
+		cred->cr_expire = jiffies;
+		rpcauth_lru_add(cred);
+		/* Race breaker */
+		if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
+			rpcauth_lru_remove(cred);
+	} else if (rpcauth_unhash_cred(cred)) {
+		rpcauth_lru_remove(cred);
+		if (refcount_dec_and_test(&cred->cr_count))
+			goto destroy;
 	}
-
-	if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
-		return;
-	if (!list_empty(&cred->cr_lru)) {
-		number_cred_unused--;
-		list_del_init(&cred->cr_lru);
-	}
-	if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
-		if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
-			cred->cr_expire = jiffies;
-			list_add_tail(&cred->cr_lru, &cred_unused);
-			number_cred_unused++;
-			goto out_nodestroy;
-		}
-		if (!rpcauth_unhash_cred(cred)) {
-			/* We were hashed and someone looked us up... */
-			goto out_nodestroy;
-		}
-	}
-	spin_unlock(&rpc_credcache_lock);
-	cred->cr_ops->crdestroy(cred);
+out:
+	rcu_read_unlock();
 	return;
-out_nodestroy:
-	spin_unlock(&rpc_credcache_lock);
+destroy:
+	rcu_read_unlock();
+	cred->cr_ops->crdestroy(cred);
 }
 EXPORT_SYMBOL_GPL(put_rpccred);
 
-__be32 *
-rpcauth_marshcred(struct rpc_task *task, __be32 *p)
+/**
+ * rpcauth_marshcred - Append RPC credential to end of @xdr
+ * @task: controlling RPC task
+ * @xdr: xdr_stream containing initial portion of RPC Call header
+ *
+ * On success, an appropriate verifier is added to @xdr, @xdr is
+ * updated to point past the verifier, and zero is returned.
+ * Otherwise, @xdr is in an undefined state and a negative errno
+ * is returned.
+ */
+int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct rpc_cred	*cred = task->tk_rqstp->rq_cred;
-
-	dprintk("RPC: %5u marshaling %s cred %p\n",
-		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
+	const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 
-	return cred->cr_ops->crmarshal(task, p);
+	return ops->crmarshal(task, xdr);
 }
 
-__be32 *
-rpcauth_checkverf(struct rpc_task *task, __be32 *p)
+/**
+ * rpcauth_wrap_req_encode - XDR encode the RPC procedure
+ * @task: controlling RPC task
+ * @xdr: stream where on-the-wire bytes are to be marshalled
+ *
+ * On success, @xdr contains the encoded and wrapped message.
+ * Otherwise, @xdr is in an undefined state.
+ */
+int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct rpc_cred	*cred = task->tk_rqstp->rq_cred;
-
-	dprintk("RPC: %5u validating %s cred %p\n",
-		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
+	kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
 
-	return cred->cr_ops->crvalidate(task, p);
+	encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
+	return 0;
 }
+EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
 
-static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
-				   __be32 *data, void *obj)
+/**
+ * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
+ * @task: controlling RPC task
+ * @xdr: stream where on-the-wire bytes are to be marshalled
+ *
+ * On success, @xdr contains the encoded and wrapped message,
+ * and zero is returned. Otherwise, @xdr is in an undefined
+ * state and a negative errno is returned.
+ */
+int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct xdr_stream xdr;
+	const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 
-	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data);
-	encode(rqstp, &xdr, obj);
+	return ops->crwrap_req(task, xdr);
 }
 
+/**
+ * rpcauth_checkverf - Validate verifier in RPC Reply header
+ * @task: controlling RPC task
+ * @xdr: xdr_stream containing RPC Reply header
+ *
+ * Return values:
+ *   %0: Verifier is valid. @xdr now points past the verifier.
+ *   %-EIO: Verifier is corrupted or message ended early.
+ *   %-EACCES: Verifier is intact but not valid.
+ *   %-EPROTONOSUPPORT: Server does not support the requested auth type.
+ *
+ * When a negative errno is returned, @xdr is left in an undefined
+ * state.
+ */
 int
-rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp,
-		__be32 *data, void *obj)
+rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 
-	dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
-			task->tk_pid, cred->cr_ops->cr_name, cred);
-	if (cred->cr_ops->crwrap_req)
-		return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
-	/* By default, we encode the arguments normally. */
-	rpcauth_wrap_req_encode(encode, rqstp, data, obj);
-	return 0;
+	return ops->crvalidate(task, xdr);
 }
 
-static int
-rpcauth_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
-			  __be32 *data, void *obj)
+/**
+ * rpcauth_unwrap_resp_decode - Invoke XDR decode function
+ * @task: controlling RPC task
+ * @xdr: stream where the Reply message resides
+ *
+ * Returns zero on success; otherwise a negative errno is returned.
+ */
+int
+rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct xdr_stream xdr;
+	kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data);
-	return decode(rqstp, &xdr, obj);
+	return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp);
 }
+EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode);
 
+/**
+ * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred
+ * @task: controlling RPC task
+ * @xdr: stream where the Reply message resides
+ *
+ * Returns zero on success; otherwise a negative errno is returned.
+ */
 int
-rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp,
-		__be32 *data, void *obj)
+rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
+{
+	const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
+
+	return ops->crunwrap_resp(task, xdr);
+}
+
+bool
+rpcauth_xmit_need_reencode(struct rpc_task *task)
 {
 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 
-	dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
-			task->tk_pid, cred->cr_ops->cr_name, cred);
-	if (cred->cr_ops->crunwrap_resp)
-		return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
-						   data, obj);
-	/* By default, we decode the arguments normally. */
-	return rpcauth_unwrap_req_decode(decode, rqstp, data, obj);
+	if (!cred || !cred->cr_ops->crneed_reencode)
+		return false;
+	return cred->cr_ops->crneed_reencode(task);
 }
 
 int
@@ -753,8 +837,6 @@ rpcauth_refreshcred(struct rpc_task *task)
 			goto out;
 		cred = task->tk_rqstp->rq_cred;
 	}
-	dprintk("RPC: %5u refreshing %s cred %p\n",
-		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 
 	err = cred->cr_ops->crrefresh(task);
 out:
@@ -768,8 +850,6 @@ rpcauth_invalcred(struct rpc_task *task)
 {
 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 
-	dprintk("RPC: %5u invalidating %s cred %p\n",
-		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 	if (cred)
 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 }
@@ -783,10 +863,7 @@ rpcauth_uptodatecred(struct rpc_task *task)
 		test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 }
 
-static struct shrinker rpc_cred_shrinker = {
-	.shrink = rpcauth_cache_shrinker,
-	.seeks = DEFAULT_SEEKS,
-};
+static struct shrinker *rpc_cred_shrinker;
 
 int __init rpcauth_init_module(void)
 {
@@ -795,10 +872,17 @@ int __init rpcauth_init_module(void)
 	err = rpc_init_authunix();
 	if (err < 0)
 		goto out1;
-	err = rpc_init_generic_auth();
-	if (err < 0)
+	rpc_cred_shrinker = shrinker_alloc(0, "sunrpc_cred");
+	if (!rpc_cred_shrinker) {
+		err = -ENOMEM;
 		goto out2;
-	register_shrinker(&rpc_cred_shrinker);
+	}
+
+	rpc_cred_shrinker->count_objects = rpcauth_cache_shrink_count;
+	rpc_cred_shrinker->scan_objects = rpcauth_cache_shrink_scan;
+
+	shrinker_register(rpc_cred_shrinker);
+
 	return 0;
 out2:
 	rpc_destroy_authunix();
@@ -809,6 +893,5 @@ out1:
 void rpcauth_remove_module(void)
 {
 	rpc_destroy_authunix();
-	rpc_destroy_generic_auth();
-	unregister_shrinker(&rpc_cred_shrinker);
+	shrinker_free(rpc_cred_shrinker);
 }