diff options
Diffstat (limited to 'net/netlabel/netlabel_domainhash.c')
| -rw-r--r-- | net/netlabel/netlabel_domainhash.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/net/netlabel/netlabel_domainhash.c b/net/netlabel/netlabel_domainhash.c index 0bfeaab88ef..d37b7f80fa3 100644 --- a/net/netlabel/netlabel_domainhash.c +++ b/net/netlabel/netlabel_domainhash.c @@ -35,6 +35,7 @@ #include <linux/spinlock.h> #include <linux/string.h> #include <linux/audit.h> +#include <linux/slab.h> #include <net/netlabel.h> #include <net/cipso_ipv4.h> #include <asm/bug.h> @@ -50,9 +51,12 @@ struct netlbl_domhsh_tbl { }; /* Domain hash table */ -/* XXX - updates should be so rare that having one spinlock for the entire - * hash table should be okay */ +/* updates should be so rare that having one spinlock for the entire hash table + * should be okay */ static DEFINE_SPINLOCK(netlbl_domhsh_lock); +#define netlbl_domhsh_rcu_deref(p) \ + rcu_dereference_check(p, rcu_read_lock_held() || \ + lockdep_is_held(&netlbl_domhsh_lock)) static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL; static struct netlbl_dom_map *netlbl_domhsh_def = NULL; @@ -106,7 +110,8 @@ static void netlbl_domhsh_free_entry(struct rcu_head *entry) * Description: * This is the hashing function for the domain hash table, it returns the * correct bucket number for the domain. The caller is responsibile for - * calling the rcu_read_[un]lock() functions. + * ensuring that the hash table is protected with either a RCU read lock or the + * hash table lock. * */ static u32 netlbl_domhsh_hash(const char *key) @@ -120,7 +125,7 @@ static u32 netlbl_domhsh_hash(const char *key) for (iter = 0, val = 0, len = strlen(key); iter < len; iter++) val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter]; - return val & (rcu_dereference(netlbl_domhsh)->size - 1); + return val & (netlbl_domhsh_rcu_deref(netlbl_domhsh)->size - 1); } /** @@ -130,7 +135,8 @@ static u32 netlbl_domhsh_hash(const char *key) * Description: * Searches the domain hash table and returns a pointer to the hash table * entry if found, otherwise NULL is returned. The caller is responsibile for - * the rcu hash table locks (i.e. the caller much call rcu_read_[un]lock()). + * ensuring that the hash table is protected with either a RCU read lock or the + * hash table lock. * */ static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain) @@ -141,7 +147,7 @@ static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain) if (domain != NULL) { bkt = netlbl_domhsh_hash(domain); - bkt_list = &rcu_dereference(netlbl_domhsh)->tbl[bkt]; + bkt_list = &netlbl_domhsh_rcu_deref(netlbl_domhsh)->tbl[bkt]; list_for_each_entry_rcu(iter, bkt_list, list) if (iter->valid && strcmp(iter->domain, domain) == 0) return iter; @@ -159,8 +165,8 @@ static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain) * Searches the domain hash table and returns a pointer to the hash table * entry if an exact match is found, if an exact match is not present in the * hash table then the default entry is returned if valid otherwise NULL is - * returned. The caller is responsibile for the rcu hash table locks - * (i.e. the caller much call rcu_read_[un]lock()). + * returned. The caller is responsibile ensuring that the hash table is + * protected with either a RCU read lock or the hash table lock. * */ static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain) @@ -169,7 +175,7 @@ static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain) entry = netlbl_domhsh_search(domain); if (entry == NULL) { - entry = rcu_dereference(netlbl_domhsh_def); + entry = netlbl_domhsh_rcu_deref(netlbl_domhsh_def); if (entry != NULL && !entry->valid) entry = NULL; } @@ -306,8 +312,11 @@ int netlbl_domhsh_add(struct netlbl_dom_map *entry, struct netlbl_af6list *tmp6; #endif /* IPv6 */ + /* XXX - we can remove this RCU read lock as the spinlock protects the + * entire function, but before we do we need to fixup the + * netlbl_af[4,6]list RCU functions to do "the right thing" with + * respect to rcu_dereference() when only a spinlock is held. */ rcu_read_lock(); - spin_lock(&netlbl_domhsh_lock); if (entry->domain != NULL) entry_old = netlbl_domhsh_search(entry->domain); |