On Thu, 20 Jan 2005, Ingo Molnar wrote: > > anyway, here's my first patch again, with s/trylock_test/can_lock/.
I don't want to break all the other architectures. Or at least not most of them. Especially since I was hoping to do a -pre2 soon (well, like today, but I guess that's out..) and make the 2.6.11 cycle shorter than 2.6.10. So I'd like to now _first_ get > spin_can_lock(lock) > read_can_lock(lock) > write_can_lock(lock) for at least most architectures (ie for me at a minimum that is x86, x86-64, ia64 and ppc64 - and obviously the "always true" cases for the UP version). Ok? Also, I've already made sure that I can't apply any half-measures by mistake by undoing the mess that it was before, and making sure that any patches I get have to be "clean slate". That said, I like how just the _renaming_ of the thing (and making them all consistent) made your BUILD_LOCK_OPS() helper macro much simpler. So I'm convinced that this is the right solution - I just want to not screw up other architectures. 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?): Linus > --- linux/include/linux/spinlock.h.orig > +++ linux/include/linux/spinlock.h > @@ -584,4 +584,10 @@ static inline int bit_spin_is_locked(int > #define DEFINE_SPINLOCK(x) spinlock_t x = SPIN_LOCK_UNLOCKED > #define DEFINE_RWLOCK(x) rwlock_t x = RW_LOCK_UNLOCKED > > +/** > + * spin_can_lock - would spin_trylock() succeed? > + * @lock: the spinlock in question. > + */ > +#define spin_can_lock(lock) (!spin_is_locked(lock)) > + > #endif /* __LINUX_SPINLOCK_H */ > --- linux/include/asm-i386/spinlock.h.orig > +++ linux/include/asm-i386/spinlock.h > @@ -188,6 +188,18 @@ typedef struct { > > #define rwlock_is_locked(x) ((x)->lock != RW_LOCK_BIAS) > > +/** > + * read_can_lock - would read_trylock() succeed? > + * @lock: the rwlock in question. > + */ > +#define read_can_lock(x) (atomic_read((atomic_t *)&(x)->lock) > 0) > + > +/** > + * write_can_lock - would write_trylock() succeed? > + * @lock: the rwlock in question. > + */ > +#define write_can_lock(x) ((x)->lock == RW_LOCK_BIAS) > + > /* > * On x86, we implement read-write locks as a 32-bit counter > * with the high bit (sign) being the "contended" bit. > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/