Messages in this thread | | | Date | Tue, 5 Jun 2007 09:58:06 -0400 (EDT) | From | "John Anthony Kazos Jr." <> | Subject | Re: SLUB: Return ZERO_SIZE_PTR for kmalloc(0) |
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> > The name says exactly what it is. It's not at all dreadful. If we're going > > to return a special value in the zero-size case (and in only that case) as a > > valid pointer instead of actually allocating one byte and treating it as > > zero, what we have is...a zero-size pointer. > > No, what we have is a sizeof(pointer) sized pointer pointing to an object of > size zero. ZERO_SIZE_PTR is butt-ugly. With a really ugly butt.
sizeof(pointer) is the object. ZERO_SIZE_PTR is the value stored in that object. Would you prefer PTR_TO_ZERO_SIZE_OBJ_VAL?
Maybe you would prefer ZERO_SIZE_OBJ instead. What you have is "a pointer object which points to a zero-sized object".
What if there were some construct in the kernel that never got deleted? We'll call it "struct foo * bar_ctl". What would you call a pointer to this? "bar_ctl_ptr". Or even "foo_ptr". So "ZERO_SIZE_OBJ_PTR" is the most correct form, and "ZERO_SIZE_PTR" is a convenient shortening. "ZERO_PTR" is too short and also confuses with NULL because NULL is a zero-value object, rather than a non-zero--value pointer to a zero-size object. - 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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