Re: [PATCH] CONFIG_PACKET_MMAP should depend on MMU

[Robin Getz]

On Mon 9 Apr 2007 05:50, Wu, Bryan pondered:
> On Mon, 2007-04-09 at 11:01 +0800, Aubrey Li wrote:
> > The option CONFIG_PACKET_MMAP should depend on MMU.
> >
> > Signed-off-by: Aubrey.Li <aubreylee@xxxxxxxxx>
> > ---
> >  net/packet/Kconfig |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/net/packet/Kconfig b/net/packet/Kconfig
> > index 34ff93f..959c272 100644
> > --- a/net/packet/Kconfig
> > +++ b/net/packet/Kconfig
> > @@ -17,7 +17,7 @@ config PACKET
> >
> >  config PACKET_MMAP
> >  	bool "Packet socket: mmapped IO"
> > -	depends on PACKET
> > +	depends on PACKET && MMU
> >  	help
> >  	  If you say Y here, the Packet protocol driver will use an IO
> >  	  mechanism that results in faster communication.
>
> Yeah, this is a bug found on blackfin arch and it is also for other
> NOMMU arch. Is there any solution for this? We think Aubrey's idea
> works.
>

I would hardly say that disabling a feature should be classified as "works". 

"works" would be re-writing packet/af_packet.c:packet_mmap() so it doesn't use 
vm_insert_page (which I think is the major/only problem) or putting some 
proper #ifdef MMU to get the intended functionality.

David - I know you have been reworking the noMMU vma handling - is there a 
solution to vm_insert_page?

-Robin
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