Re: [PATCH 2.6] 1/7 create kstrdup library function

[Paulo Marques <pmarques@grupopie.com>]

Pekka Enberg wrote:
> At some point in time, I wrote:
> 
>>>kstrdup() is a special-case _memory allocator_ (not so much a string
>>>operation) so I think it should go into mm/slab.c where we currently
>>>have kcalloc().
> 
> 
> On Tue, 01 Feb 2005 17:00:17 +0000, Paulo Marques <pmarques@grupopie.com> wrote:
> 
>>I was following Rusty Russell's approach. Also, I believe this is more
>>intuitive because the standard libc strdup function is declared in string.h.
>>
>>However, I really don't have strong feelings either way, so if the
>>majority agrees that this should be in mm/slab, its fine by me.
> 
> 
> Intuitive, perhaps, but I think it's wrong. I don't like it because it
> makes string operations depend on slab. Furthermore, kstrdup() is not
> a string operation. It is about memory allocation, really, just like
> kcalloc().

I agree with the "is like kcalloc" argument in the sense that it does an 
allocation + something else. But in this case the "something else" is in 
fact a string operation, so this just seem to be in the middle.

> One possible way to clean this up would be to extract the
> standard-like allocators (kmalloc, kcalloc, and kstrdup) from
> mm/slab.c and move them into a separate file.

I don't like this approach. From a quick grep you get 4972 kmalloc's in 
.c files in the kernel tree and only 35 kstrdup's. Moving kstrdup around 
is still just 7 patches, kmalloc is a much bigger problem.

Anyway, as I said before, if more people believe that moving kstrdup 
into mm/slab.c is the way to go, then its fine by me. The problem I was 
trying to solve was having several versions of strdup-like functions all 
around the kernel, and this problem gets fixed either way. Right now, 
the poll goes something like this:

string.c: me, Rusty Russell
slab.c: Pekka Enberg

I think we need more votes :)

-- 
Paulo Marques - www.grupopie.com

All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke (1729 - 1797)