Merge branch 'pm-sleep'

[cascardo/linux.git] / net / netfilter / nf_conntrack_core.c

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 9f530ad..4cbda4b 100644 (file)
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -83,6 +83,13 @@ void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
        spin_lock(lock);
        while (unlikely(nf_conntrack_locks_all)) {
                spin_unlock(lock);
+
+               /*
+                * Order the 'nf_conntrack_locks_all' load vs. the
+                * spin_unlock_wait() loads below, to ensure
+                * that 'nf_conntrack_locks_all_lock' is indeed held:
+                */
+               smp_rmb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
                spin_unlock_wait(&nf_conntrack_locks_all_lock);
                spin_lock(lock);
        }
@@ -128,6 +135,14 @@ static void nf_conntrack_all_lock(void)
        spin_lock(&nf_conntrack_locks_all_lock);
        nf_conntrack_locks_all = true;
 
+       /*
+        * Order the above store of 'nf_conntrack_locks_all' against
+        * the spin_unlock_wait() loads below, such that if
+        * nf_conntrack_lock() observes 'nf_conntrack_locks_all'
+        * we must observe nf_conntrack_locks[] held:
+        */
+       smp_mb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
+
        for (i = 0; i < CONNTRACK_LOCKS; i++) {
                spin_unlock_wait(&nf_conntrack_locks[i]);
        }
@@ -135,7 +150,13 @@ static void nf_conntrack_all_lock(void)
 
 static void nf_conntrack_all_unlock(void)
 {
-       nf_conntrack_locks_all = false;
+       /*
+        * All prior stores must be complete before we clear
+        * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
+        * might observe the false value but not the entire
+        * critical section:
+        */
+       smp_store_release(&nf_conntrack_locks_all, false);
        spin_unlock(&nf_conntrack_locks_all_lock);
 }