On Fri, 29 Aug 2008 17:34:16 -0600
Matthew Wilcox <matthew@xxxxxx> wrote:
>
> I see you're fixing up the original patch without commenting on this at
> all.
Sob. I'm just slogging away trying to get my tree to compile.
One more build error and I drop it all.
> On Fri, Aug 22, 2008 at 03:36:25PM -0600, Matthew Wilcox wrote:
> > On Fri, Aug 22, 2008 at 01:56:38PM -0700, akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> > > Subject: Separate atomic_t declaration from asm/atomic.h into asm/atomic_def.h
> > > From: Huang Ying <ying.huang@xxxxxxxxx>
> > >
> > > asm/atomic.h contains both declaration and implementation of atomic_t. So
> > > there are some implementation related files included in asm/atomic.h. And
> > > atomic_t is a typedef. Combination of above makes it impossible to use
> > > atomic_t in files included by atomic.h. Such as atomic_t can not be used
> > > in linux/kernel.h on i386, because it is included by asm/atomic.h.
> > >
> > > It is reasonable to separate declaration from implementation. So a new
> > > file atomic_def.h is added for every architecture to accommodate the
> > > declaration of atomic_t.
> >
> > Seems to me like all architectures could use:
> >
> > +++ include/linux/atomic_type.h
> > +typedef struct { volatile int counter; } atomic_t;
> > +#ifdef CONFIG_64BIT
> > +typedef struct { volatile long counter; } atomic64_t;
> > +#endif
> >
> > S390 has an __aligned__((4)) on theirs -- is this really necessary?
> > Doesn't s390 align ints to 4 bytes automatically? If it doesn't, it
> > shouldn't be harmful to add it to other architectures (iirc m68k only
> > requires 2-byte alignment for ints ... hmm, wonder if their atomic_t is
> > really atomic if, say, it cross a page boundary ...)
> >
Sounds right to me.
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