On Thu, Jul 23, 2020 at 1:53 AM Guenter Roeck <li...@roeck-us.net> wrote:
> On 7/22/20 3:52 PM, Rich Felker wrote:
> > On Tue, Jul 21, 2020 at 07:38:40PM -0700, Guenter Roeck wrote:
> >> On Thu, Dec 12, 2019 at 11:38:43AM +0900, Kuninori Morimoto wrote:
> >>> From: Kuninori Morimoto <kuninori.morimoto...@renesas.com>
> >>>
> >>> __delay() is used from kernel module.
> >>> We need EXPORT_SYMBOL(), otherwise we will get compile error.
> >>>
> >>> ERROR: "__delay" [drivers/net/phy/mdio-cavium.ko] undefined!
> >>>
> >>> Signed-off-by: Kuninori Morimoto <kuninori.morimoto...@renesas.com>
> >>
> >> I must admit that this patch completely baffles me. __delay was
> >> already exported, only elsewhere in the file. With this patch
> >> in place, it is exported twice, and all sh builds in -next fail
> >> with
> >>
> >> In file included from include/linux/linkage.h:7,
> >> from arch/sh/include/asm/bug.h:5,
> >> from include/linux/bug.h:5,
> >> from include/linux/thread_info.h:12,
> >> from include/asm-generic/current.h:5,
> >> from ./arch/sh/include/generated/asm/current.h:1,
> >> from include/linux/sched.h:12,
> >> from arch/sh/lib/delay.c:8:
> >> include/linux/export.h:67:36: error: redefinition of '__ksymtab___delay'
> >>
> >> Guenter
> >>
> >>> ---
> >>> arch/sh/lib/delay.c | 1 +
> >>> 1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/arch/sh/lib/delay.c b/arch/sh/lib/delay.c
> >>> index dad8e6a..540e670 100644
> >>> --- a/arch/sh/lib/delay.c
> >>> +++ b/arch/sh/lib/delay.c
> >>> @@ -29,6 +29,7 @@ void __delay(unsigned long loops)
> >>> : "0" (loops)
> >>> : "t");
> >>> }
> >>> +EXPORT_SYMBOL(__delay);
> >>>
> >>> inline void __const_udelay(unsigned long xloops)
> >>> {
> >
> > I presently have a revert of this commit in queue for next. If it's
> > sufficiently breaking (and especially if there are other regressions
> > that need to be fixed, see the pmd_free thing) I could try to get it
> > in for 5.8 still but that's getting a bit late.
> >
>
> The patch in mainline is ok. It appears that it has been applied
> again in -next.
>
> "git log --oneline v5.7.. arch/sh/lib/delay.c" on top of next-20200721
> reports:
>
> ee0e4f15dfd4 (origin/akpm) sh: add missing EXPORT_SYMBOL() for __delay
> d1f56f318d23 sh: add missing EXPORT_SYMBOL() for __delay
>
> Maybe it just needs to be dropped from the akpm tree in -next ?
IMHO all of them should be dropped/reverted.
__delay is an internal implementation detail, not to be used by drivers.
See also include/asm-generic/delay.h:
/* Undefined functions to get compile-time errors */
...
extern void __delay(unsigned long loops);
Cfr. '[PATCH] Revert "sh: add missing EXPORT_SYMBOL() for __delay"'
https://lore.kernel.org/lkml/20200608080636.27862-1-geert+rene...@glider.be/
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
