提交 31be5bf1 编写于 作者: T Trond Myklebust

SUNRPC: Convert the credcache lookup code to use RCU

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
上级 e092bdcd
......@@ -16,6 +16,7 @@
#include <linux/sunrpc/xdr.h>
#include <asm/atomic.h>
#include <linux/rcupdate.h>
/* size of the nodename buffer */
#define UNX_MAXNODENAME 32
......@@ -35,6 +36,7 @@ struct rpc_credops;
struct rpc_cred {
struct hlist_node cr_hash; /* hash chain */
struct list_head cr_lru; /* lru garbage collection */
struct rcu_head cr_rcu;
struct rpc_auth * cr_auth;
const struct rpc_credops *cr_ops;
#ifdef RPC_DEBUG
......@@ -50,6 +52,7 @@ struct rpc_cred {
};
#define RPCAUTH_CRED_NEW 0
#define RPCAUTH_CRED_UPTODATE 1
#define RPCAUTH_CRED_HASHED 2
#define RPCAUTH_CRED_MAGIC 0x0f4aa4f0
......
......@@ -112,6 +112,14 @@ rpcauth_release(struct rpc_auth *auth)
static DEFINE_SPINLOCK(rpc_credcache_lock);
static void
rpcauth_unhash_cred_locked(struct rpc_cred *cred)
{
hlist_del_rcu(&cred->cr_hash);
smp_mb__before_clear_bit();
clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
}
/*
* Initialize RPC credential cache
*/
......@@ -166,8 +174,7 @@ rpcauth_clear_credcache(struct rpc_cred_cache *cache)
cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
get_rpccred(cred);
list_move_tail(&cred->cr_lru, &free);
smp_wmb();
hlist_del_init(&cred->cr_hash);
rpcauth_unhash_cred_locked(cred);
}
}
spin_unlock(&rpc_credcache_lock);
......@@ -207,8 +214,7 @@ rpcauth_prune_expired(struct list_head *free)
continue;
get_rpccred(cred);
list_add_tail(&cred->cr_lru, free);
smp_wmb();
hlist_del_init(&cred->cr_hash);
rpcauth_unhash_cred_locked(cred);
}
}
......@@ -218,10 +224,12 @@ rpcauth_prune_expired(struct list_head *free)
static void
rpcauth_gc_credcache(struct rpc_cred_cache *cache, struct list_head *free)
{
if (time_before(jiffies, cache->nextgc))
if (list_empty(&cred_unused) || time_before(jiffies, cache->nextgc))
return;
spin_lock(&rpc_credcache_lock);
cache->nextgc = jiffies + cache->expire;
rpcauth_prune_expired(free);
spin_unlock(&rpc_credcache_lock);
}
/*
......@@ -234,42 +242,57 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
LIST_HEAD(free);
struct rpc_cred_cache *cache = auth->au_credcache;
struct hlist_node *pos;
struct rpc_cred *new = NULL,
*cred = NULL,
*entry;
struct rpc_cred *cred = NULL,
*entry, *new;
int nr = 0;
if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
nr = acred->uid & RPC_CREDCACHE_MASK;
retry:
spin_lock(&rpc_credcache_lock);
hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
rcu_read_lock();
hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
if (!entry->cr_ops->crmatch(acred, entry, flags))
continue;
spin_lock(&rpc_credcache_lock);
if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
spin_unlock(&rpc_credcache_lock);
continue;
}
cred = get_rpccred(entry);
hlist_del(&entry->cr_hash);
spin_unlock(&rpc_credcache_lock);
break;
}
if (new) {
if (cred)
list_add_tail(&new->cr_lru, &free);
else
cred = new;
}
if (cred) {
hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
rcu_read_unlock();
if (cred != NULL) {
rpcauth_gc_credcache(cache, &free);
goto found;
}
rpcauth_gc_credcache(cache, &free);
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
new = auth->au_ops->crcreate(auth, acred, flags);
if (IS_ERR(new)) {
cred = new;
goto out;
}
if (!cred) {
new = auth->au_ops->crcreate(auth, acred, flags);
if (!IS_ERR(new))
goto retry;
spin_lock(&rpc_credcache_lock);
hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
if (!entry->cr_ops->crmatch(acred, entry, flags))
continue;
cred = get_rpccred(entry);
break;
}
if (cred == NULL) {
cred = new;
} else if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
} else
list_add_tail(&new->cr_lru, &free);
rpcauth_prune_expired(&free);
cache->nextgc = jiffies + cache->expire;
spin_unlock(&rpc_credcache_lock);
found:
if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
&& cred->cr_ops->cr_init != NULL
&& !(flags & RPCAUTH_LOOKUP_NEW)) {
int res = cred->cr_ops->cr_init(auth, cred);
......@@ -278,8 +301,9 @@ rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
cred = ERR_PTR(res);
}
}
return (struct rpc_cred *) cred;
rpcauth_destroy_credlist(&free);
out:
return cred;
}
struct rpc_cred *
......@@ -357,21 +381,20 @@ void
put_rpccred(struct rpc_cred *cred)
{
/* Fast path for unhashed credentials */
if (!hlist_unhashed(&cred->cr_hash))
if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
goto need_lock;
if (!atomic_dec_and_test(&cred->cr_count))
return;
goto out_destroy;
need_lock:
if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
return;
if (!list_empty(&cred->cr_lru))
list_del_init(&cred->cr_lru);
if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
hlist_del(&cred->cr_hash);
else if (!hlist_unhashed(&cred->cr_hash)) {
rpcauth_unhash_cred_locked(cred);
else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
cred->cr_expire = jiffies;
list_add_tail(&cred->cr_lru, &cred_unused);
spin_unlock(&rpc_credcache_lock);
......
......@@ -694,15 +694,25 @@ gss_destroy_ctx(struct gss_cl_ctx *ctx)
}
static void
gss_destroy_cred(struct rpc_cred *rc)
gss_free_cred(struct gss_cred *gss_cred)
{
struct gss_cred *cred = container_of(rc, struct gss_cred, gc_base);
dprintk("RPC: gss_free_cred %p\n", gss_cred);
if (gss_cred->gc_ctx)
gss_put_ctx(gss_cred->gc_ctx);
kfree(gss_cred);
}
dprintk("RPC: gss_destroy_cred \n");
static void
gss_free_cred_callback(struct rcu_head *head)
{
struct gss_cred *gss_cred = container_of(head, struct gss_cred, gc_base.cr_rcu);
gss_free_cred(gss_cred);
}
if (cred->gc_ctx)
gss_put_ctx(cred->gc_ctx);
kfree(cred);
static void
gss_destroy_cred(struct rpc_cred *cred)
{
call_rcu(&cred->cr_rcu, gss_free_cred_callback);
}
/*
......
......@@ -93,11 +93,23 @@ unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
}
static void
unx_destroy_cred(struct rpc_cred *rcred)
unx_free_cred(struct unx_cred *unx_cred)
{
struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
dprintk("RPC: unx_free_cred %p\n", unx_cred);
kfree(unx_cred);
}
static void
unx_free_cred_callback(struct rcu_head *head)
{
struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
unx_free_cred(unx_cred);
}
kfree(cred);
static void
unx_destroy_cred(struct rpc_cred *cred)
{
call_rcu(&cred->cr_rcu, unx_free_cred_callback);
}
/*
......
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