Convert bit_spin_lock to new locking bitops. Slub can use the non-atomic store
version to clear (Christoph?)
Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
---
include/linux/bit_spinlock.h | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
Index: linux-2.6/include/linux/bit_spinlock.h
===================================================================
--- linux-2.6.orig/include/linux/bit_spinlock.h
+++ linux-2.6/include/linux/bit_spinlock.h
@@ -18,7 +18,7 @@ static inline void bit_spin_lock(int bit
*/
preempt_disable();
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
- while (test_and_set_bit(bitnum, addr)) {
+ while (unlikely(test_and_set_bit_lock(bitnum, addr))) {
while (test_bit(bitnum, addr)) {
preempt_enable();
cpu_relax();
@@ -36,7 +36,7 @@ static inline int bit_spin_trylock(int b
{
preempt_disable();
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
- if (test_and_set_bit(bitnum, addr)) {
+ if (unlikely(test_and_set_bit_lock(bitnum, addr))) {
preempt_enable();
return 0;
}
@@ -50,10 +50,28 @@ static inline int bit_spin_trylock(int b
*/
static inline void bit_spin_unlock(int bitnum, unsigned long *addr)
{
+#ifdef CONFIG_DEBUG_SPINLOCK
+ BUG_ON(!test_bit(bitnum, addr));
+#endif
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+ clear_bit_unlock(bitnum, addr);
+#endif
+ preempt_enable();
+ __release(bitlock);
+}
+
+/*
+ * bit-based spin_unlock()
+ * non-atomic version, which can be used eg. if the bit lock itself is
+ * protecting the rest of the flags in the word.
+ */
+static inline void __bit_spin_unlock(int bitnum, unsigned long *addr)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
BUG_ON(!test_bit(bitnum, addr));
- smp_mb__before_clear_bit();
- clear_bit(bitnum, addr);
+#endif
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+ __clear_bit_unlock(bitnum, addr);
#endif
preempt_enable();
__release(bitlock);
-
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