Re: [patch 1/7] slab: introduce kzfree()

[Pekka Enberg <penberg@cs.helsinki.fi>]

Hi Hugh.

Hugh Dickins wrote:
> Thanks for that, I remember it now.
> 
> Okay, that's some justification for kfree(const void *).
> 
> But I fail to see it as a justification for kzfree(const void *):
> if someone has "const char *string = kmalloc(size)" and then
> wants that string zeroed before it is freed, then I think it's
> quite right to cast out the const when calling kzfree().

Quite frankly, I fail to see how kzfree() is fundamentally different 
from kfree(). I don't see kzfree() as a memset() + kfree() but rather as 
a kfree() "and make sure no one sees my data". So the zeroing happens 
_after_ you've invalidated the pointer with kzfree() so there's no 
"zeroing of buffer going on". So the way I see it, Linus' argument for 
having const for kfree() applies to kzfree().

That said, if you guys think it's a merge blocker, by all means remove 
the const. I just want few less open-coded ksize() users, that's all.

			Pekka