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

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/arch/tile/include/asm/spinlock_32.h b/kernel/arch/tile/include/asm/spinlock_32.h
index c0a77b38d..b14b1ba5b 100644
--- a/kernel/arch/tile/include/asm/spinlock_32.h
+++ b/kernel/arch/tile/include/asm/spinlock_32.h
@@ -41,8 +41,12 @@ static inline int arch_spin_is_locked(arch_spinlock_t *lock)
 	 * to claim the lock is held, since it will be momentarily
 	 * if not already.  There's no need to wait for a "valid"
 	 * lock->next_ticket to become available.
+	 * Use READ_ONCE() to ensure that calling this in a loop is OK.
 	 */
-	return lock->next_ticket != lock->current_ticket;
+	int curr = READ_ONCE(lock->current_ticket);
+	int next = READ_ONCE(lock->next_ticket);
+
+	return next != curr;
 }
 
 void arch_spin_lock(arch_spinlock_t *lock);