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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-25 12:41:29 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-25 12:41:29 -0700 |
commit | c86ad14d305d2429c3da19462440bac50c183def (patch) | |
tree | bd794cd72476661faf82c440063c217bb978ce44 /net | |
parent | a2303849a6b4b7ba59667091e00d6bb194071d9a (diff) | |
parent | f06628638cf6e75f179742b6c1b35076965b9fdd (diff) | |
download | linux-c86ad14d305d2429c3da19462440bac50c183def.tar.gz |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: "The locking tree was busier in this cycle than the usual pattern - a couple of major projects happened to coincide. The main changes are: - implement the atomic_fetch_{add,sub,and,or,xor}() API natively across all SMP architectures (Peter Zijlstra) - add atomic_fetch_{inc/dec}() as well, using the generic primitives (Davidlohr Bueso) - optimize various aspects of rwsems (Jason Low, Davidlohr Bueso, Waiman Long) - optimize smp_cond_load_acquire() on arm64 and implement LSE based atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() on arm64 (Will Deacon) - introduce smp_acquire__after_ctrl_dep() and fix various barrier mis-uses and bugs (Peter Zijlstra) - after discovering ancient spin_unlock_wait() barrier bugs in its implementation and usage, strengthen its semantics and update/fix usage sites (Peter Zijlstra) - optimize mutex_trylock() fastpath (Peter Zijlstra) - ... misc fixes and cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits) locking/atomic: Introduce inc/dec variants for the atomic_fetch_$op() API locking/barriers, arch/arm64: Implement LDXR+WFE based smp_cond_load_acquire() locking/static_keys: Fix non static symbol Sparse warning locking/qspinlock: Use __this_cpu_dec() instead of full-blown this_cpu_dec() locking/atomic, arch/tile: Fix tilepro build locking/atomic, arch/m68k: Remove comment locking/atomic, arch/arc: Fix build locking/Documentation: Clarify limited control-dependency scope locking/atomic, arch/rwsem: Employ atomic_long_fetch_add() locking/atomic, arch/qrwlock: Employ atomic_fetch_add_acquire() locking/atomic, arch/mips: Convert to _relaxed atomics locking/atomic, arch/alpha: Convert to _relaxed atomics locking/atomic: Remove the deprecated atomic_{set,clear}_mask() functions locking/atomic: Remove linux/atomic.h:atomic_fetch_or() locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() locking/atomic: Fix atomic64_relaxed() bits locking/atomic, arch/xtensa: Implement atomic_fetch_{add,sub,and,or,xor}() locking/atomic, arch/x86: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() locking/atomic, arch/tile: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() ...
Diffstat (limited to 'net')
-rw-r--r-- | net/netfilter/nf_conntrack_core.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 9f530adad10d..4cbda4bd8926 100644 --- 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); } |