Messages in this thread | | | Date | Mon, 12 Dec 2005 15:42:24 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] Introduce atomic_long_t and asm-generic/atomic.h |
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Christoph Lameter <clameter@engr.sgi.com> wrote: > > +#ifdef ATOMIC64_INIT > + > +#define ATOMIC_LONG_INIT(i) ATOMIC64_INIT(i) > +#define atomic_long_t atomic64_t > +#define atomic_long_read(v) atomic64_read(v) > +#define atomic_long_set(v,i) atomic64_set(v,i) > +#define atomic_long_inc(v) atomic64_inc(v) > +#define atomic_long_dec(v) atomic64_dec(v) > +#define atomic_long_add(i,v) atomic64_add(i,v) > +#define atomic_long_sub(i,v) atomic64_sub(i,v) > + > +#else > + > +#define ATOMIC_LONG_INIT(i) ATOMIC_INIT(i) > +#define atomic_long_t atomic_t > +#define atomic_long_read(v) atomic_read(v) > +#define atomic_long_set(v,i) atomic_set(v,i) > +#define atomic_long_inc(v) atomic_inc(v) > +#define atomic_long_dec(v) atomic_dec(v) > +#define atomic_long_add(i,v) atomic_add(i,v) > +#define atomic_long_sub(i,v) atomic_sub(i,v) > + > +#endif
It's sneaky, but it's not really good enough, IMO.
It assumes that sizeof(long) = sizeof(int) ifndef ATOMIC64_INIT. Which is true, but there are still problems. For example, I'd reasonably expect this:
printk("%ld", atomic_long_read(v));
to not produce a warning. It may also lead to long*/int* warnings or build errors.
Also, it kind-of assumes that each 64-bit arch uses `long' for its 64-bit value. sh64, for example, appears to use `long long'.
Perhaps all this can be fixed by filling the above macros with typecasts. Remember that typecasted lvals are illegal with gcc-4.x.
Or we bite the bullet and implement these guys in each arch... - 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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