Messages in this thread Patch in this message | | | Date | Thu, 20 Jan 2005 17:47:41 +0100 | From | Ingo Molnar <> | Subject | Re: [patch 1/3] spinlock fix #1, *_can_lock() primitives |
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* Linus Torvalds <torvalds@osdl.org> 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?):
(untested) ia64 version below. Differs from x86/x64.
Ingo
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- linux/include/asm-ia64/spinlock.h.orig +++ linux/include/asm-ia64/spinlock.h @@ -128,8 +128,27 @@ typedef struct { #define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 } #define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0) -#define rwlock_is_locked(x) (*(volatile int *) (x) != 0) +/** + * read_can_lock - would read_trylock() succeed? + * @lock: the rwlock in question. + */ +static inline int read_can_lock(rwlock_t *rw) +{ + return *(volatile int *)rw >= 0; +} + +/** + * write_can_lock - would write_trylock() succeed? + * @lock: the rwlock in question. + */ +static inline int write_can_lock(rwlock_t *rw) +{ + return *(volatile int *)rw == 0; +} + + /* + * On x86, we implement read-write locks as a 32-bit counter #define _raw_read_lock(rw) \ do { \ rwlock_t *__read_lock_ptr = (rw); \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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