SUNRPC: Convert the credcache lookup code to use RCU

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-06-24 15:55:26 -04:00
parent e092bdcd93
commit 31be5bf15f
4 changed files with 92 additions and 44 deletions

View file

@ -16,6 +16,7 @@
#include <linux/sunrpc/xdr.h> #include <linux/sunrpc/xdr.h>
#include <asm/atomic.h> #include <asm/atomic.h>
#include <linux/rcupdate.h>
/* size of the nodename buffer */ /* size of the nodename buffer */
#define UNX_MAXNODENAME 32 #define UNX_MAXNODENAME 32
@ -35,6 +36,7 @@ struct rpc_credops;
struct rpc_cred { struct rpc_cred {
struct hlist_node cr_hash; /* hash chain */ struct hlist_node cr_hash; /* hash chain */
struct list_head cr_lru; /* lru garbage collection */ struct list_head cr_lru; /* lru garbage collection */
struct rcu_head cr_rcu;
struct rpc_auth * cr_auth; struct rpc_auth * cr_auth;
const struct rpc_credops *cr_ops; const struct rpc_credops *cr_ops;
#ifdef RPC_DEBUG #ifdef RPC_DEBUG
@ -50,6 +52,7 @@ struct rpc_cred {
}; };
#define RPCAUTH_CRED_NEW 0 #define RPCAUTH_CRED_NEW 0
#define RPCAUTH_CRED_UPTODATE 1 #define RPCAUTH_CRED_UPTODATE 1
#define RPCAUTH_CRED_HASHED 2
#define RPCAUTH_CRED_MAGIC 0x0f4aa4f0 #define RPCAUTH_CRED_MAGIC 0x0f4aa4f0

View file

@ -112,6 +112,14 @@ rpcauth_release(struct rpc_auth *auth)
static DEFINE_SPINLOCK(rpc_credcache_lock); 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 * 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); cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
get_rpccred(cred); get_rpccred(cred);
list_move_tail(&cred->cr_lru, &free); list_move_tail(&cred->cr_lru, &free);
smp_wmb(); rpcauth_unhash_cred_locked(cred);
hlist_del_init(&cred->cr_hash);
} }
} }
spin_unlock(&rpc_credcache_lock); spin_unlock(&rpc_credcache_lock);
@ -207,8 +214,7 @@ rpcauth_prune_expired(struct list_head *free)
continue; continue;
get_rpccred(cred); get_rpccred(cred);
list_add_tail(&cred->cr_lru, free); list_add_tail(&cred->cr_lru, free);
smp_wmb(); rpcauth_unhash_cred_locked(cred);
hlist_del_init(&cred->cr_hash);
} }
} }
@ -218,10 +224,12 @@ rpcauth_prune_expired(struct list_head *free)
static void static void
rpcauth_gc_credcache(struct rpc_cred_cache *cache, struct list_head *free) 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; return;
spin_lock(&rpc_credcache_lock);
cache->nextgc = jiffies + cache->expire; cache->nextgc = jiffies + cache->expire;
rpcauth_prune_expired(free); 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); LIST_HEAD(free);
struct rpc_cred_cache *cache = auth->au_credcache; struct rpc_cred_cache *cache = auth->au_credcache;
struct hlist_node *pos; struct hlist_node *pos;
struct rpc_cred *new = NULL, struct rpc_cred *cred = NULL,
*cred = NULL, *entry, *new;
*entry;
int nr = 0; int nr = 0;
if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
nr = acred->uid & RPC_CREDCACHE_MASK; nr = acred->uid & RPC_CREDCACHE_MASK;
retry:
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);
spin_unlock(&rpc_credcache_lock);
break;
}
rcu_read_unlock();
if (cred != NULL) {
rpcauth_gc_credcache(cache, &free);
goto found;
}
new = auth->au_ops->crcreate(auth, acred, flags);
if (IS_ERR(new)) {
cred = new;
goto out;
}
spin_lock(&rpc_credcache_lock); spin_lock(&rpc_credcache_lock);
hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) { hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
if (!entry->cr_ops->crmatch(acred, entry, flags)) if (!entry->cr_ops->crmatch(acred, entry, flags))
continue; continue;
cred = get_rpccred(entry); cred = get_rpccred(entry);
hlist_del(&entry->cr_hash);
break; break;
} }
if (new) { if (cred == NULL) {
if (cred)
list_add_tail(&new->cr_lru, &free);
else
cred = new;
}
if (cred) {
hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
}
rpcauth_gc_credcache(cache, &free);
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
if (!cred) {
new = auth->au_ops->crcreate(auth, acred, flags);
if (!IS_ERR(new))
goto retry;
cred = new; 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 && cred->cr_ops->cr_init != NULL
&& !(flags & RPCAUTH_LOOKUP_NEW)) { && !(flags & RPCAUTH_LOOKUP_NEW)) {
int res = cred->cr_ops->cr_init(auth, cred); int res = cred->cr_ops->cr_init(auth, cred);
@ -278,8 +301,9 @@ retry:
cred = ERR_PTR(res); cred = ERR_PTR(res);
} }
} }
rpcauth_destroy_credlist(&free);
return (struct rpc_cred *) cred; out:
return cred;
} }
struct rpc_cred * struct rpc_cred *
@ -357,21 +381,20 @@ void
put_rpccred(struct rpc_cred *cred) put_rpccred(struct rpc_cred *cred)
{ {
/* Fast path for unhashed credentials */ /* Fast path for unhashed credentials */
if (!hlist_unhashed(&cred->cr_hash)) if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
goto need_lock; goto need_lock;
if (!atomic_dec_and_test(&cred->cr_count)) if (!atomic_dec_and_test(&cred->cr_count))
return; return;
goto out_destroy; goto out_destroy;
need_lock: need_lock:
if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock)) if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
return; return;
if (!list_empty(&cred->cr_lru)) if (!list_empty(&cred->cr_lru))
list_del_init(&cred->cr_lru); list_del_init(&cred->cr_lru);
if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0) if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
hlist_del(&cred->cr_hash); rpcauth_unhash_cred_locked(cred);
else if (!hlist_unhashed(&cred->cr_hash)) { else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
cred->cr_expire = jiffies; cred->cr_expire = jiffies;
list_add_tail(&cred->cr_lru, &cred_unused); list_add_tail(&cred->cr_lru, &cred_unused);
spin_unlock(&rpc_credcache_lock); spin_unlock(&rpc_credcache_lock);

View file

@ -694,15 +694,25 @@ gss_destroy_ctx(struct gss_cl_ctx *ctx)
} }
static void 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) static void
gss_put_ctx(cred->gc_ctx); gss_destroy_cred(struct rpc_cred *cred)
kfree(cred); {
call_rcu(&cred->cr_rcu, gss_free_cred_callback);
} }
/* /*

View file

@ -93,11 +93,23 @@ unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
} }
static void 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);
}
kfree(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);
}
static void
unx_destroy_cred(struct rpc_cred *cred)
{
call_rcu(&cred->cr_rcu, unx_free_cred_callback);
} }
/* /*