X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Flinux%2Flockref.h;h=c8929c3832db26d00d80f96e524afbb0e75c4df1;hb=57f4257eae33e036125973858934730250d464e3;hp=f279ed9a91631cca7f236d20ef5a29d152332932;hpb=2b2322d662237a4b635a755df15e21b9ff80716b;p=firefly-linux-kernel-4.4.55.git

diff --git a/include/linux/lockref.h b/include/linux/lockref.h
index f279ed9a9163..c8929c3832db 100644
--- a/include/linux/lockref.h
+++ b/include/linux/lockref.h
@@ -15,10 +15,15 @@
  */
 
 #include <linux/spinlock.h>
+#include <generated/bounds.h>
+
+#define USE_CMPXCHG_LOCKREF \
+	(IS_ENABLED(CONFIG_ARCH_USE_CMPXCHG_LOCKREF) && \
+	 IS_ENABLED(CONFIG_SMP) && !BLOATED_SPINLOCKS)
 
 struct lockref {
 	union {
-#ifdef CONFIG_CMPXCHG_LOCKREF
+#if USE_CMPXCHG_LOCKREF
 		aligned_u64 lock_count;
 #endif
 		struct {
@@ -36,4 +41,10 @@ extern int lockref_put_or_lock(struct lockref *);
 extern void lockref_mark_dead(struct lockref *);
 extern int lockref_get_not_dead(struct lockref *);
 
+/* Must be called under spinlock for reliable results */
+static inline int __lockref_is_dead(const struct lockref *l)
+{
+	return ((int)l->count < 0);
+}
+
 #endif /* __LINUX_LOCKREF_H */