[PATCH] Add EXPORT_SYMBOL(ksize);

[PATCH] Add EXPORT_SYMBOL(ksize);

[Tetsuo Handa]

mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

---
 mm/slab.c |    1 +
 mm/slob.c |    1 +
 2 files changed, 2 insertions(+)

--- linux-2.6-mm.orig/mm/slab.c
+++ linux-2.6-mm/mm/slab.c
@@ -4479,3 +4479,4 @@ size_t ksize(const void *objp)
 
 	return obj_size(virt_to_cache(objp));
 }
+EXPORT_SYMBOL(ksize);
--- linux-2.6-mm.orig/mm/slob.c
+++ linux-2.6-mm/mm/slob.c
@@ -495,6 +495,7 @@ size_t ksize(const void *block)
 	else
 		return sp->page.private;
 }
+EXPORT_SYMBOL(ksize);
 
 struct kmem_cache {
 	unsigned int size, align;

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Adrian Bunk]

On Sun, Dec 02, 2007 at 05:43:39PM +0900, Tetsuo Handa wrote:
> 
> mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
>...

That's due to the fact that my patch to remove this unused export from 
slub was not yet applied...

Where is the modular in-kernel user?

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Tetsuo Handa]

Hello.

Adrian Bunk wrote:
> > mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
> That's due to the fact that my patch to remove this unused export from 
> slub was not yet applied...
So, removing exports is intended thing?

> Where is the modular in-kernel user?
I don't know.
But I think ksize() should be available to kernel modules as well as kmalloc() etc.

Thanks.

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Arnaldo Carvalho de Melo]

Em Mon, Dec 03, 2007 at 06:34:20AM +0900, Tetsuo Handa escreveu:
> Hello.
> 
> Adrian Bunk wrote:
> > > mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
> > That's due to the fact that my patch to remove this unused export from 
> > slub was not yet applied...
> So, removing exports is intended thing?

The ones that are leftovers from past, valid, uses, yes. Kudos to Adrian
for being the zealot in action!
 
> > Where is the modular in-kernel user?
> I don't know.
> But I think ksize() should be available to kernel modules as well as kmalloc() etc.

Why do you think so? You have to justify that with some valid use.
 
- Arnaldo

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Tetsuo Handa]

Hello.

Arnaldo Carvalho de Melo wrote:
> > But I think ksize() should be available to kernel modules as well as kmalloc() etc.
> Why do you think so? You have to justify that with some valid use.
Is there an alternative function?
If not, it sounds to me that this is a regression.
We couldn't know how much memory was allocated by kmalloc() in 2.4 era, and we can know it 2.6 era.
But are we going back to 2.4 era for out-of-tree kernel modules?

Thanks.

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Adrian Bunk]

On Mon, Dec 03, 2007 at 08:41:44PM +0900, Tetsuo Handa wrote:
> Hello.
> 
> Arnaldo Carvalho de Melo wrote:
> > > But I think ksize() should be available to kernel modules as well as kmalloc() etc.
> > Why do you think so? You have to justify that with some valid use.
> Is there an alternative function?

The question is not whether there's an alternative function.

The kernel does not waste memory for all users by providing a fixed API 
for external modules, the purpose of the kernel is to provide everything 
required for what is shipped with the kernel.

Simply send the patch adding the exports when you submit your module for 
inclusion in the kernel.

> If not, it sounds to me that this is a regression.

That sounds strange considering that slab and slob AFAIR never exported 
this symbol and only slub in 2.6.22 and 2.6.23 exports it.

> We couldn't know how much memory was allocated by kmalloc() in 2.4 era, and we can know it 2.6 era.
> But are we going back to 2.4 era for out-of-tree kernel modules?

The interesting fact is that there are zero in-kernel modules using it.

> Thanks.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Pekka Enberg]

Hi,

On Mon, Dec 03, 2007 at 08:41:44PM +0900, Tetsuo Handa wrote:
> > We couldn't know how much memory was allocated by kmalloc() in 2.4 era, and we can know it 2.6 era.
> > But are we going back to 2.4 era for out-of-tree kernel modules?

On Dec 3, 2007 3:57 PM, Adrian Bunk <bunk@kernel.org> wrote:
> The interesting fact is that there are zero in-kernel modules using it.

Yeah, and now that we have krealloc() I don't expect that many callers
actually need ksize() either.

                                Pekka

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Matt Mackall]

On Mon, Dec 03, 2007 at 04:07:33PM +0200, Pekka Enberg wrote:
> Hi,
> 
> On Mon, Dec 03, 2007 at 08:41:44PM +0900, Tetsuo Handa wrote:
> > > We couldn't know how much memory was allocated by kmalloc() in 2.4 era, and we can know it 2.6 era.
> > > But are we going back to 2.4 era for out-of-tree kernel modules?
> 
> On Dec 3, 2007 3:57 PM, Adrian Bunk <bunk@kernel.org> wrote:
> > The interesting fact is that there are zero in-kernel modules using it.
> 
> Yeah, and now that we have krealloc() I don't expect that many callers
> actually need ksize() either.

Yes, most of them ought not exist.

-- 
Mathematics is the supreme nostalgia of our time.

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Andrew Morton]

On Sun, 2 Dec 2007 14:48:42 +0100
Adrian Bunk <bunk@kernel.org> wrote:

> On Sun, Dec 02, 2007 at 05:43:39PM +0900, Tetsuo Handa wrote:
> > 
> > mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
> >...
> 
> That's due to the fact that my patch to remove this unused export from 
> slub was not yet applied...
> 
> Where is the modular in-kernel user?
> 

binfmt_flat.c, binfmt_elf_fdpic.c.

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Adrian Bunk]

On Mon, Dec 03, 2007 at 03:34:59PM -0800, Andrew Morton wrote:
> On Sun, 2 Dec 2007 14:48:42 +0100
> Adrian Bunk <bunk@kernel.org> wrote:
> 
> > On Sun, Dec 02, 2007 at 05:43:39PM +0900, Tetsuo Handa wrote:
> > > 
> > > mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
> > >...
> > 
> > That's due to the fact that my patch to remove this unused export from 
> > slub was not yet applied...
> > 
> > Where is the modular in-kernel user?
> > 
> 
> binfmt_flat.c, binfmt_elf_fdpic.c.

I could have sworn I had checked that both are bools, but BINFMT_FLAT is 
actually a tristate.

Is anyone actually using binfmt_flat modular (considering it's only 
available for !MMU embedded systems)? If yes, then only exporting 
ksize() will not be enough for getting it working modular...

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Adrian Bunk]

On Thu, Dec 06, 2007 at 10:02:48PM +0100, Adrian Bunk wrote:
> On Mon, Dec 03, 2007 at 03:34:59PM -0800, Andrew Morton wrote:
> > On Sun, 2 Dec 2007 14:48:42 +0100
> > Adrian Bunk <bunk@kernel.org> wrote:
> > 
> > > On Sun, Dec 02, 2007 at 05:43:39PM +0900, Tetsuo Handa wrote:
> > > > 
> > > > mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
> > > >...
> > > 
> > > That's due to the fact that my patch to remove this unused export from 
> > > slub was not yet applied...
> > > 
> > > Where is the modular in-kernel user?
> > > 
> > 
> > binfmt_flat.c, binfmt_elf_fdpic.c.
> 
> I could have sworn I had checked that both are bools, but BINFMT_FLAT is 
> actually a tristate.
> 
> Is anyone actually using binfmt_flat modular (considering it's only 
> available for !MMU embedded systems)? If yes, then only exporting 
> ksize() will not be enough for getting it working modular...

Considering it even lacks a MODULE_LICENSE("GPL") I do very much suspect 
it simply lacks any use case.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Bernd Schmidt]

A couple of Cc:s added.

Adrian Bunk wrote:
> On Mon, Dec 03, 2007 at 03:34:59PM -0800, Andrew Morton wrote:
>> On Sun, 2 Dec 2007 14:48:42 +0100
>> Adrian Bunk <bunk@kernel.org> wrote:
>>
>>> On Sun, Dec 02, 2007 at 05:43:39PM +0900, Tetsuo Handa wrote:
>>>> mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
>>>> ...
>>> That's due to the fact that my patch to remove this unused export from 
>>> slub was not yet applied...
>>>
>>> Where is the modular in-kernel user?
>>>
>> binfmt_flat.c, binfmt_elf_fdpic.c.
> 
> I could have sworn I had checked that both are bools, but BINFMT_FLAT is 
> actually a tristate.
> 
> Is anyone actually using binfmt_flat modular (considering it's only 
> available for !MMU embedded systems)? If yes, then only exporting 
> ksize() will not be enough for getting it working modular...

We're not using modular binfmt_flat on the Blackfin, but I can't speak
for other architectures.


Bernd
-- 
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Re: [PATCH] Add EXPORT_SYMBOL(ksize);

[Greg Ungerer]

Bernd Schmidt wrote:
> A couple of Cc:s added.
> 
> Adrian Bunk wrote:
>> On Mon, Dec 03, 2007 at 03:34:59PM -0800, Andrew Morton wrote:
>>> On Sun, 2 Dec 2007 14:48:42 +0100
>>> Adrian Bunk <bunk@kernel.org> wrote:
>>>
>>>> On Sun, Dec 02, 2007 at 05:43:39PM +0900, Tetsuo Handa wrote:
>>>>> mm/slub.c exports ksize(), but mm/slob.c and mm/slab.c don't. I don't know why.
>>>>> ...
>>>> That's due to the fact that my patch to remove this unused export from 
>>>> slub was not yet applied...
>>>>
>>>> Where is the modular in-kernel user?
>>>>
>>> binfmt_flat.c, binfmt_elf_fdpic.c.
>> I could have sworn I had checked that both are bools, but BINFMT_FLAT is 
>> actually a tristate.
>>
>> Is anyone actually using binfmt_flat modular (considering it's only 
>> available for !MMU embedded systems)? If yes, then only exporting 
>> ksize() will not be enough for getting it working modular...
> 
> We're not using modular binfmt_flat on the Blackfin, but I can't speak
> for other architectures.

I don't know of any architectures that do (or have ever) used
these as modules.

Regards
Greg


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