[PATCH] lz4: make LZ4HC_setExternalDict as non-static

[PATCH] lz4: make LZ4HC_setExternalDict as non-static

[Arnd Bergmann]

kbuild warns for exported static symbols. This one seems to
be meant as an external API but does not have any in-kernel
users:

WARNING: "LZ4HC_setExternalDict" [vmlinux] is a static EXPORT_SYMBOL

I suppose the function should not just get removed since it would
be nice to stay close to the upstream version of lz4hc, so just
make it global.

The modpost commit is correct, but is listed here as the one
that introduced the warning.

Fixes: 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 lib/lz4/lz4hc_compress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/lz4/lz4hc_compress.c b/lib/lz4/lz4hc_compress.c
index 176f03b83e56..e1075293c009 100644
--- a/lib/lz4/lz4hc_compress.c
+++ b/lib/lz4/lz4hc_compress.c
@@ -642,7 +642,7 @@ EXPORT_SYMBOL(LZ4_loadDictHC);
 
 /* compression */
 
-static void LZ4HC_setExternalDict(
+void LZ4HC_setExternalDict(
 	LZ4HC_CCtx_internal *ctxPtr,
 	const BYTE *newBlock)
 {
-- 
2.20.0

Re: [PATCH] lz4: make LZ4HC_setExternalDict as non-static

[Denis Efremov]

Hi,

> kbuild warns for exported static symbols. This one seems to
> be meant as an external API but does not have any in-kernel
> users:
> 
> WARNING: "LZ4HC_setExternalDict" [vmlinux] is a static EXPORT_SYMBOL
> 
> I suppose the function should not just get removed since it would
> be nice to stay close to the upstream version of lz4hc, so just
> make it global.

I'm not sure what is better here. But just in case, I sent a different
patch that removes EXPORT_SYMBOL from this function some time ago:
https://lkml.org/lkml/2019/7/8/842

I checked first that this functions is indeed static in the original lib[1]
and this symbol is not used in kernel.

[1] https://github.com/lz4/lz4/blob/dev/lib/lz4hc.c#L1054

Thanks,
Denis

Re: [PATCH] lz4: make LZ4HC_setExternalDict as non-static

[Arnd Bergmann]

On Fri, Sep 6, 2019 at 6:21 PM Denis Efremov <efremov@linux.com> wrote:
>
> Hi,
>
> > kbuild warns for exported static symbols. This one seems to
> > be meant as an external API but does not have any in-kernel
> > users:
> >
> > WARNING: "LZ4HC_setExternalDict" [vmlinux] is a static EXPORT_SYMBOL
> >
> > I suppose the function should not just get removed since it would
> > be nice to stay close to the upstream version of lz4hc, so just
> > make it global.
>
> I'm not sure what is better here. But just in case, I sent a different
> patch that removes EXPORT_SYMBOL from this function some time ago:
> https://lkml.org/lkml/2019/7/8/842
>
> I checked first that this functions is indeed static in the original lib[1]
> and this symbol is not used in kernel.
>
> [1] https://github.com/lz4/lz4/blob/dev/lib/lz4hc.c#L1054

Ah, good. Your patch is the better fix then.

      Arnd

Re: [PATCH] lz4: make LZ4HC_setExternalDict as non-static

[Masahiro Yamada]

On Sat, Sep 7, 2019 at 3:43 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Fri, Sep 6, 2019 at 6:21 PM Denis Efremov <efremov@linux.com> wrote:
> >
> > Hi,
> >
> > > kbuild warns for exported static symbols. This one seems to
> > > be meant as an external API but does not have any in-kernel
> > > users:
> > >
> > > WARNING: "LZ4HC_setExternalDict" [vmlinux] is a static EXPORT_SYMBOL
> > >
> > > I suppose the function should not just get removed since it would
> > > be nice to stay close to the upstream version of lz4hc, so just
> > > make it global.

When you make the symbol global, you need to
provide a prototype declaration in a global header.
(include/linux/lz4.h in this case)

Otherwise, nobody cannot call this function anyway.

I prefer Denis's fix-up.




> > I'm not sure what is better here. But just in case, I sent a different
> > patch that removes EXPORT_SYMBOL from this function some time ago:
> > https://lkml.org/lkml/2019/7/8/842
> >
> > I checked first that this functions is indeed static in the original lib[1]
> > and this symbol is not used in kernel.
> >
> > [1] https://github.com/lz4/lz4/blob/dev/lib/lz4hc.c#L1054
>
> Ah, good. Your patch is the better fix then.
>
>       Arnd



-- 
Best Regards
Masahiro Yamada