On 03/02/23 at 08:12am, Arnd Bergmann wrote:
> On Thu, Mar 2, 2023, at 05:12, Baoquan He wrote:
> > On 03/01/23 at 03:06pm, Arnd Bergmann wrote:
> >
> > Yeah, defining mmiowb() to wmb() directly is also good to me. I tried
> > to comb including sequence and find where asm/io.h is included, but
> > failed. Mainly asm/mmiowb.h including asm/io.h will cause below
> > compiling error, the asm/io.h need see mmiowb_set_pending which is
> > defnined in asm-generic/mmiowb.h. Moving asm-generic/mmiowb.h to above
> > asm/io.h can also fix the compiling error.
> >
> > =============
> > diff --git a/arch/mips/include/asm/mmiowb.h b/arch/mips/include/asm/mmiowb.h
> > index a40824e3ef8e..cae2745935bc 100644
> > --- a/arch/mips/include/asm/mmiowb.h
> > +++ b/arch/mips/include/asm/mmiowb.h
> > @@ -2,10 +2,8 @@
> > #ifndef _ASM_MMIOWB_H
> > #define _ASM_MMIOWB_H
> >
> > +#include <asm-generic/mmiowb.h>
> > #include <asm/io.h>
> >
> > #define mmiowb() iobarrier_w()
> > -
> > -#include <asm-generic/mmiowb.h>
> > -
> > #endif /* _ASM_MMIOWB_H */
>
> According to the comment in asm-generic/mmiowb.h, the intention is
> to have the mmiowb definition before the #include, though this would
> only be necessary if there was an "#ifndef mmiowb" fallback in that
> file. If the definition to wmb() works, I'd go for that one and
> leave the include order unchanged.
I didn't add definition of outb(), so it caused the compiling error at
below. Adding it can fix that. I will leave the asm/mmiowb.h as is
since no issue now.
In file included from ./arch/mips/include/asm/io.h:611,
from ./arch/mips/include/asm/mmiowb.h:5,
from ./include/linux/spinlock.h:65,
from ./include/linux/ipc.h:5,
from ./include/uapi/linux/sem.h:5,
from ./include/linux/sem.h:5,
from ./include/linux/compat.h:14,
from arch/mips/kernel/asm-offsets.c:12:
./include/asm-generic/io.h: In function ‘_outb’:
./include/asm-generic/io.h:46:24: error: implicit declaration of function ‘mmiowb_set_pending’ [-Werror=implicit-function-declaration]
46 | #define __io_aw() mmiowb_set_pending()
| ^~~~~~~~~~~~~~~~~~
./include/asm-generic/io.h:54:24: note: in expansion of macro ‘__io_aw’
54 | #define __io_paw() __io_aw()
| ^~~~~~~
./include/asm-generic/io.h:585:9: note: in expansion of macro ‘__io_paw’
585 | __io_paw();
| ^~~~~~~~
