Re: [PATCH 1/2] vmalloc: use ZERO_SIZE_PTR / ZERO_OR_NULL_PTR

On 02/28/2012 01:44 PM, Dan Carpenter wrote:

On Tue, Feb 28, 2012 at 01:33:59PM +0400, Dmitry Antipov wrote:

...

• Fix vmap() to return ZERO_SIZE_PTR if 0 pages are requested;
• fix __vmalloc_node_range() to return ZERO_SIZE_PTR if 0 bytes are requested;
• fix __vunmap() to check passed pointer with ZERO_OR_NULL_PTR.

Why?

1) it was requested by the subsystem (co?)maintainer, see http://lkml.org/lkml/2012/1/27/475; 2) this looks to be a convenient way to trace/debug zero-size allocation errors (although I don't advocate it as a best way).

Dmitry