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

From: Paulo Marques
Date: Wed Feb 02 2005 - 07:20:01 EST


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@xxxxxxxxxxxx> 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)
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