These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / arch / tile / include / asm / spinlock_64.h

diff --git a/kernel/arch/tile/include/asm/spinlock_64.h b/kernel/arch/tile/include/asm/spinlock_64.h
index 9a12b9c..b9718fb 100644 (file)
--- a/kernel/arch/tile/include/asm/spinlock_64.h
+++ b/kernel/arch/tile/include/asm/spinlock_64.h
@@ -18,6 +18,8 @@
 #ifndef _ASM_TILE_SPINLOCK_64_H
 #define _ASM_TILE_SPINLOCK_64_H
 
+#include <linux/compiler.h>
+
 /* Shifts and masks for the various fields in "lock". */
 #define __ARCH_SPIN_CURRENT_SHIFT      17
 #define __ARCH_SPIN_NEXT_MASK          0x7fff
@@ -44,7 +46,8 @@ static inline u32 arch_spin_next(u32 val)
 /* The lock is locked if a task would have to wait to get it. */
 static inline int arch_spin_is_locked(arch_spinlock_t *lock)
 {
-       u32 val = lock->lock;
+       /* Use READ_ONCE() to ensure that calling this in a loop is OK. */
+       u32 val = READ_ONCE(lock->lock);
        return arch_spin_current(val) != arch_spin_next(val);
 }