Re: [PATCH] slab: Redefine ZERO_SIZE_PTR to include ERR_PTR range

[Matthew Wilcox <willy@xxxxxxxxxxxxx>]

On Thu, Oct 10, 2019 at 02:22:40PM +0000, Christopher Lameter wrote:
> On Thu, 10 Oct 2019, Shyam Saini wrote:
> 
> > This will help error related to ERR_PTR stand out better.
> 
> Maybe make ZERO_SIZE_PTR an ERRNO value instead? Then allow ERR_PTRs to be
> used instead of ZERO_SIZE_PTRs
> 
> ERRNO_ZERO_OBJECT
> 
> or something like that?

I was wondering about something like that too, but allocating zero bytes
isn't actually an error, and if we have code that does something like:

	void *p = my_funky_alloc(size, ...);

	if (IS_ERR(p))
		return PTR_ERR(p);

then we might get this errno returned to userspace.

The change is definitely worth thinking about.