Subject: Re: [PATCH 2/2] Fix compile error of pgtable-ppc64.h

From: Greg KH <[email-masked]>
Date: Wed, 29 Jan 2014 10:45:44 -0800

On Tue, Jan 28, 2014 at 05:52:42PM +0530, Aneesh Kumar K.V wrote:
> From: Li Zhong <[email-masked]>
> 
> It seems that forward declaration couldn't work well with typedef, use
> struct spinlock directly to avoiding following build errors:
> 
> In file included from include/linux/spinlock.h:81,
>                  from include/linux/seqlock.h:35,
>                  from include/linux/time.h:5,
>                  from include/uapi/linux/timex.h:56,
>                  from include/linux/timex.h:56,
>                  from include/linux/sched.h:17,
>                  from arch/powerpc/kernel/asm-offsets.c:17:
> include/linux/spinlock_types.h:76: error: redefinition of typedef 'spinlock_t'
> /root/linux-next/arch/powerpc/include/asm/pgtable-ppc64.h:563: note: previous declaration of 'spinlock_t' was here
> 
> build fix for upstream SHA1: b3084f4db3aeb991c507ca774337c7e7893ed04f
> for 3.13 stable series

I don't understand, why is this needed?  Is there a corrisponding patch
upstream that already does this?  What went wrong with a "normal"
backport of the patch to 3.13?

confused,

greg k-h