| Message ID | 1511089467-20525-1-git-send-email-geert@linux-m68k.org (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Eduardo Valentin |
| Headers | show |
Hello Geert, On Sun, Nov 19, 2017 at 12:04:27PM +0100, Geert Uytterhoeven wrote: > With gcc-4.1.2: > > drivers/thermal/hisi_thermal.c: In function ‘hisi_thermal_probe’: > drivers/thermal/hisi_thermal.c:530: warning: type qualifiers ignored on function return type > > Remove the "const" keyword to fix this. Interesting. I intentionally asked Daniel to include the modifier because sparse pointed this to me: This patch adds this issue to hisi driver (sparse) drivers/thermal/hisi_thermal.c:398:24: warning: incorrect type in assignment (different modifiers) drivers/thermal/hisi_thermal.c:398:24: expected int ( *platform_probe )( ... ) drivers/thermal/hisi_thermal.c:398:24: got void const * which makes sense to me to be const, given that it is receiving the return of a function which returns a const void *. nclude/linux/of_device.h:extern const void *of_device_get_match_data(const struct device *dev); Cheers,
Hi Eduardo, On Mon, Jan 1, 2018 at 7:21 PM, Eduardo Valentin <edubezval@gmail.com> wrote: > On Sun, Nov 19, 2017 at 12:04:27PM +0100, Geert Uytterhoeven wrote: >> With gcc-4.1.2: >> >> drivers/thermal/hisi_thermal.c: In function ‘hisi_thermal_probe’: >> drivers/thermal/hisi_thermal.c:530: warning: type qualifiers ignored on function return type >> >> Remove the "const" keyword to fix this. > > Interesting. > > I intentionally asked Daniel to include the modifier because sparse > pointed this to me: > > This patch adds this issue to hisi driver (sparse) > > drivers/thermal/hisi_thermal.c:398:24: warning: incorrect type in assignment (different modifiers) > drivers/thermal/hisi_thermal.c:398:24: expected int ( *platform_probe )( ... ) > drivers/thermal/hisi_thermal.c:398:24: got void const * Sparse doesn't like assigning void pointers to function pointers without a cast. > which makes sense to me to be const, given that it is receiving the return > of a function which returns a const void *. > nclude/linux/of_device.h:extern const void *of_device_get_match_data(const struct device *dev); That const applies to what is returned by of_device_get_match_data() (a const void *), not to what is returned by the returned function (an int). 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
On Sun, Nov 19, 2017 at 12:04 PM, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > With gcc-4.1.2: > > drivers/thermal/hisi_thermal.c: In function ‘hisi_thermal_probe’: > drivers/thermal/hisi_thermal.c:530: warning: type qualifiers ignored on function return type > > Remove the "const" keyword to fix this. > > Fixes: a160a465297362c5 ("thermal/drivers/hisi: Prepare to add support for other hisi platforms") > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> For future reference, this kind of warning shows up with gcc-4.2 as well, but not with gcc-4.3 or higher. I think in this case, both gcc and sparse fail to provide helpful feedback, but the code is probably better done using either a typedef for the function type, or with a structure containing the function pointer. Arnd
On Tue, Jan 02, 2018 at 12:44:29PM +0100, Arnd Bergmann wrote: > On Sun, Nov 19, 2017 at 12:04 PM, Geert Uytterhoeven > <geert@linux-m68k.org> wrote: > > With gcc-4.1.2: > > > > drivers/thermal/hisi_thermal.c: In function ‘hisi_thermal_probe’: > > drivers/thermal/hisi_thermal.c:530: warning: type qualifiers ignored on function return type > > > > Remove the "const" keyword to fix this. > > > > Fixes: a160a465297362c5 ("thermal/drivers/hisi: Prepare to add support for other hisi platforms") > > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> > > For future reference, this kind of warning shows up with gcc-4.2 as > well, but not with > gcc-4.3 or higher. I think in this case, both gcc and sparse fail to Yeah, this is correct. I do not see the same warn while using gcc-4.8. > provide helpful > feedback, but the code is probably better done using either a typedef > for the function > type, or with a structure containing the function pointer. I agree. > > Arnd
diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c index 2d855a96cdd9886c..761d0559c268b606 100644 --- a/drivers/thermal/hisi_thermal.c +++ b/drivers/thermal/hisi_thermal.c @@ -527,7 +527,7 @@ static void hisi_thermal_toggle_sensor(struct hisi_thermal_sensor *sensor, static int hisi_thermal_probe(struct platform_device *pdev) { struct hisi_thermal_data *data; - int const (*platform_probe)(struct hisi_thermal_data *); + int (*platform_probe)(struct hisi_thermal_data *); struct device *dev = &pdev->dev; int ret;
With gcc-4.1.2: drivers/thermal/hisi_thermal.c: In function ‘hisi_thermal_probe’: drivers/thermal/hisi_thermal.c:530: warning: type qualifiers ignored on function return type Remove the "const" keyword to fix this. Fixes: a160a465297362c5 ("thermal/drivers/hisi: Prepare to add support for other hisi platforms") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> --- drivers/thermal/hisi_thermal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)