Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 3 Aug 2020 12:01:29 +0200 | Subject | Re: [PATCH] sh: add missing EXPORT_SYMBOL() for __delay |
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On Thu, Jul 23, 2020 at 1:53 AM Guenter Roeck <linux@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.gx@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.gx@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+renesas@glider.be/
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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
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