Re: CVS commit: src/sys/net

[David Laight <david%l8s.co.uk@localhost>]

On Fri, Dec 11, 2015 at 11:37:29AM +0900, Kengo NAKAHARA wrote:
> # Sorry, I forgot to subscribe source-changes-d ml, I reply as
> # a new mail.
> 
> Hi,
> 
> > In article <20151210081103.E0FBBFB83%cvs.NetBSD.org@localhost>,
> > Kengo NAKAHARA <source-changes-d%NetBSD.org@localhost> wrote:
> >>-=-=-=-=-=-
> >>
> >>Module Name:	src
> >>Committed By:	knakahara
> >>Date:		Thu Dec 10 08:11:03 UTC 2015
> >>
> >>Modified Files:
> >>	src/sys/net: if_gif.c
> >>
> >>Log Message:
> >>kmem_zalloc(, KM_SLEEP) must not return NULL.
> > 
> > I would like to solicit opinions about this change and form a general
> > policy.
> > 
> > 1. I would like to reduce the use of KASSERT in the kernel, specially
> > in situations like thee above where the test can be centralized (inside
> > kmem_alloc) and avoided without being fatal.
> 
> OK, this kmem_zalloc() is not fatal. I should avoid KASSERT here.

There is no real point using KASSERT() when the immediate
dereference of NULL will have the same effect and is about as
easy to debug.

Whether kmem_alloc(KM_SLEEP) can return NULL is another matter.
Seems wrong to me - maybe even for impossible allications.
ISTR a problem waiting for KVA and phys-mem being 'difficult'.
I know that the Linux equivalent will return NULL, not sure when.
It would be useful to define that allocation for non-huge
(maybe even several MB) amounts will always sleep.

	David

-- 
David Laight: david%l8s.co.uk@localhost