[PATCH] security, keys: Optimize barrier usage for Rmw atomic bitops
From: Davidlohr Bueso <dave@stgolabs.net>
Date: 2020-01-29 18:16:33
Also in:
lkml
Subsystem:
keys/keyrings, security subsystem, the rest · Maintainers:
David Howells, Jarkko Sakkinen, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
For both set and clear_bit, we can avoid the unnecessary barriers
on non LL/SC architectures, such as x86. Instead, use the
smp_mb__{before,after}_atomic() calls.
Signed-off-by: Davidlohr Bueso <redacted>
---
security/keys/gc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 671dd730ecfc..ce7b4c22e3c4 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c@@ -102,7 +102,7 @@ void key_gc_keytype(struct key_type *ktype) key_gc_dead_keytype = ktype; set_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); - smp_mb(); + smp_mb__after_atomic(); set_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags); kdebug("schedule");
@@ -308,7 +308,7 @@ static void key_garbage_collector(struct work_struct *work) if (unlikely(gc_state & KEY_GC_REAPING_DEAD_3)) { kdebug("dead wake"); - smp_mb(); + smp_mb__before_atomic(); clear_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); wake_up_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE); }
--
2.16.4