SUNRPC: Make the credential cache hashtable size configurable
This patch allows the user to configure the credential cache hashtable size
using a new module parameter: auth_hashtable_size
When set, this parameter will be rounded up to the nearest power of two,
with a maximum allowed value of 1024 elements.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index 84d64b6..d273762 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -61,14 +61,7 @@
/*
* Client authentication handle
*/
-#define RPC_CREDCACHE_HASHBITS 4
-#define RPC_CREDCACHE_NR (1 << RPC_CREDCACHE_HASHBITS)
-struct rpc_cred_cache {
- struct hlist_head hashtable[RPC_CREDCACHE_NR];
- unsigned int hashbits;
- spinlock_t lock;
-};
-
+struct rpc_cred_cache;
struct rpc_authops;
struct rpc_auth {
unsigned int au_cslack; /* call cred size estimate */
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index eef76a1..d80f017 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -19,6 +19,15 @@
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
+#define RPC_CREDCACHE_DEFAULT_HASHBITS (4)
+struct rpc_cred_cache {
+ struct hlist_head *hashtable;
+ unsigned int hashbits;
+ spinlock_t lock;
+};
+
+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 */
@@ -29,6 +38,42 @@
static LIST_HEAD(cred_unused);
static unsigned long number_cred_unused;
+#define MAX_HASHTABLE_BITS (10)
+static int param_set_hashtbl_sz(const char *val, struct kernel_param *kp)
+{
+ unsigned long num;
+ unsigned int nbits;
+ int ret;
+
+ if (!val)
+ goto out_inval;
+ ret = strict_strtoul(val, 0, &num);
+ if (ret == -EINVAL)
+ goto out_inval;
+ nbits = fls(num);
+ if (num > (1U << nbits))
+ nbits++;
+ if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
+ goto out_inval;
+ *(unsigned int *)kp->arg = nbits;
+ return 0;
+out_inval:
+ return -EINVAL;
+}
+
+static int param_get_hashtbl_sz(char *buffer, struct kernel_param *kp)
+{
+ unsigned int nbits;
+
+ nbits = *(unsigned int *)kp->arg;
+ return sprintf(buffer, "%u", 1U << nbits);
+}
+
+#define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
+
+module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
+MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
+
static u32
pseudoflavor_to_flavor(u32 flavor) {
if (flavor >= RPC_AUTH_MAXFLAVOR)
@@ -146,18 +191,22 @@
{
struct rpc_cred_cache *new;
unsigned int hashsize;
- int i;
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (!new)
- return -ENOMEM;
- new->hashbits = RPC_CREDCACHE_HASHBITS;
+ goto out_nocache;
+ new->hashbits = auth_hashbits;
hashsize = 1U << new->hashbits;
- for (i = 0; i < hashsize; i++)
- INIT_HLIST_HEAD(&new->hashtable[i]);
+ new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
+ if (!new->hashtable)
+ goto out_nohashtbl;
spin_lock_init(&new->lock);
auth->au_credcache = new;
return 0;
+out_nohashtbl:
+ kfree(new);
+out_nocache:
+ return -ENOMEM;
}
EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
@@ -220,6 +269,7 @@
if (cache) {
auth->au_credcache = NULL;
rpcauth_clear_credcache(cache);
+ kfree(cache->hashtable);
kfree(cache);
}
}