--- zzzz-none-000/linux-3.10.107/arch/tile/include/asm/spinlock_64.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/tile/include/asm/spinlock_64.h	2021-02-04 17:41:59.000000000 +0000
@@ -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
@@ -27,7 +29,7 @@
  * Return the "current" portion of a ticket lock value,
  * i.e. the number that currently owns the lock.
  */
-static inline int arch_spin_current(u32 val)
+static inline u32 arch_spin_current(u32 val)
 {
 	return val >> __ARCH_SPIN_CURRENT_SHIFT;
 }
@@ -36,7 +38,7 @@
  * Return the "next" portion of a ticket lock value,
  * i.e. the number that the next task to try to acquire the lock will get.
  */
-static inline int arch_spin_next(u32 val)
+static inline u32 arch_spin_next(u32 val)
 {
 	return val & __ARCH_SPIN_NEXT_MASK;
 }
@@ -44,7 +46,8 @@
 /* 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);
 }