mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors
Removing explicit calls to mmiowb() from driver code means that we must
now call into the generic mmiowb_spin_{lock,unlock}() functions from the
core spinlock code. In order to elide barriers following critical
sections without any I/O writes, we also hook into the asm-generic I/O
routines.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index e089157..ed7c4d6 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -57,6 +57,7 @@
#include <linux/stringify.h>
#include <linux/bottom_half.h>
#include <asm/barrier.h>
+#include <asm/mmiowb.h>
/*
@@ -178,6 +179,7 @@ static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
{
__acquire(lock);
arch_spin_lock(&lock->raw_lock);
+ mmiowb_spin_lock();
}
#ifndef arch_spin_lock_flags
@@ -189,15 +191,22 @@ do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lo
{
__acquire(lock);
arch_spin_lock_flags(&lock->raw_lock, *flags);
+ mmiowb_spin_lock();
}
static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
{
- return arch_spin_trylock(&(lock)->raw_lock);
+ int ret = arch_spin_trylock(&(lock)->raw_lock);
+
+ if (ret)
+ mmiowb_spin_lock();
+
+ return ret;
}
static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
{
+ mmiowb_spin_unlock();
arch_spin_unlock(&lock->raw_lock);
__release(lock);
}