* kmap() transformation: Question about copy_user_highpage
@ 2023-10-06 18:46 Deepak R Varma
2023-10-07 4:55 ` Huacai Chen
0 siblings, 1 reply; 3+ messages in thread
From: Deepak R Varma @ 2023-10-06 18:46 UTC (permalink / raw)
To: Huacai Chen, WANG Xuerui, loongarch, linux-kernel
Cc: Ira Weiny, Fabio M. De Francesco
Hello,
I am attempting to work on replacing the kmap[_atomic]() calls by
kmap_local_page() function call. A detail on this change can be found here [0].
I would like to know if this function:
arch/loongarch/mm/init.c::copy_user_highpage()
is currently in use or is it a dead code?
If this code is not in use, can this be removed instead? However, if it is in
use, can you comment why kmap_atomic() was preferred over kmap()
function call?
[0] https://lore.kernel.org/all/20201029222652.302358281@linutronix.de/
Thank you,
Deepak.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: kmap() transformation: Question about copy_user_highpage
2023-10-06 18:46 kmap() transformation: Question about copy_user_highpage Deepak R Varma
@ 2023-10-07 4:55 ` Huacai Chen
2023-10-07 13:00 ` Deepak R Varma
0 siblings, 1 reply; 3+ messages in thread
From: Huacai Chen @ 2023-10-07 4:55 UTC (permalink / raw)
To: Deepak R Varma
Cc: WANG Xuerui, loongarch, linux-kernel, Ira Weiny, Fabio M. De Francesco
Hi, Deepak,
On Sat, Oct 7, 2023 at 2:46 AM Deepak R Varma <drv@mailo.com> wrote:
>
> Hello,
> I am attempting to work on replacing the kmap[_atomic]() calls by
> kmap_local_page() function call. A detail on this change can be found here [0].
>
> I would like to know if this function:
> arch/loongarch/mm/init.c::copy_user_highpage()
> is currently in use or is it a dead code?
>
> If this code is not in use, can this be removed instead? However, if it is in
> use, can you comment why kmap_atomic() was preferred over kmap()
> function call?
I think this function will be used for the 32bit kernel, and we will
add loongarch32 support in the near future.
But on the other hand, you can replace kmap_atomic() with
kmap_local_page(), there is no special reason to use kmap_atomic().
Huacai
>
> [0] https://lore.kernel.org/all/20201029222652.302358281@linutronix.de/
>
> Thank you,
> Deepak.
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: kmap() transformation: Question about copy_user_highpage
2023-10-07 4:55 ` Huacai Chen
@ 2023-10-07 13:00 ` Deepak R Varma
0 siblings, 0 replies; 3+ messages in thread
From: Deepak R Varma @ 2023-10-07 13:00 UTC (permalink / raw)
To: Huacai Chen
Cc: WANG Xuerui, loongarch, linux-kernel, Ira Weiny, Fabio M. De Francesco
On Sat, Oct 07, 2023 at 12:55:14PM +0800, Huacai Chen wrote:
> Hi, Deepak,
Hello Huacai,
>
> On Sat, Oct 7, 2023 at 2:46 AM Deepak R Varma <drv@mailo.com> wrote:
> >
> > Hello,
> > I am attempting to work on replacing the kmap[_atomic]() calls by
> > kmap_local_page() function call. A detail on this change can be found here [0].
> >
> > I would like to know if this function:
> > arch/loongarch/mm/init.c::copy_user_highpage()
> > is currently in use or is it a dead code?
> >
> > If this code is not in use, can this be removed instead? However, if it is in
> > use, can you comment why kmap_atomic() was preferred over kmap()
> > function call?
> I think this function will be used for the 32bit kernel, and we will
> add loongarch32 support in the near future.
Okay. Sounds good.
>
> But on the other hand, you can replace kmap_atomic() with
> kmap_local_page(), there is no special reason to use kmap_atomic().
Looks like you sent in a patch. Thank you. I was working on trying to cross
compile my patch for the arch. I still would like to attempt that. Will request
your help if I get stuck.
regards,
deepak.
>
> Huacai
>
> >
> > [0] https://lore.kernel.org/all/20201029222652.302358281@linutronix.de/
> >
> > Thank you,
> > Deepak.
> >
> >
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-10-07 13:00 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2023-10-06 18:46 kmap() transformation: Question about copy_user_highpage Deepak R Varma
2023-10-07 4:55 ` Huacai Chen
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