* Linus Torvalds <[EMAIL PROTECTED]> wrote:
> I can do ppc64 myself, can others fix the other architectures (Ingo,
> shouldn't the UP case have the read/write_can_lock() cases too? And
> wouldn't you agree that it makes more sense to have the rwlock test
> variants in asm/rwlock.h?):
this one adds it to x64. (untested at the moment) This patch assumes
that we are nuking rwlock_is_locked and that there is at least a
s/rwlock_is_locked/!write_can_lock/ done to kernel/exit.c.
Ingo
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
--- linux/include/asm-x86_64/spinlock.h.orig
+++ linux/include/asm-x86_64/spinlock.h
@@ -161,7 +161,23 @@ typedef struct {
#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
-#define rwlock_is_locked(x) ((x)->lock != RW_LOCK_BIAS)
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static inline int read_can_lock(rwlock_t *rw)
+{
+ return rw->lock > 0;
+}
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static inline int write_can_lock(rwlock_t *rw)
+{
+ return rw->lock == RW_LOCK_BIAS;
+}
/*
* On x86, we implement read-write locks as a 32-bit counter
-
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