On Wed, 2014-01-29 at 10:45 -0800, Greg KH wrote:

On Tue, Jan 28, 2014 at 05:52:42PM +0530, Aneesh Kumar K.V wrote:

quoted

From: Li Zhong <redacted>

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?

There's a corresponding patch in powerpc-next that I'm about to send to
Linus today, but for the backport, the "fix" could be folded into the
original offending patch.

Cheers,
Ben.