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Groups > linux.kernel > #1557413
| From | Marc Gonzalez <marc_gonzalez@sigmadesigns.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions |
| Date | 2017-01-12 13:20 +0100 |
| Message-ID | <sYMwh-3RM-3@gated-at.bofh.it> (permalink) |
| References | (6 earlier) <sYs4y-7ZN-11@gated-at.bofh.it> <sYt0B-70-27@gated-at.bofh.it> <sYvlM-1rB-61@gated-at.bofh.it> <sYKb7-2kU-13@gated-at.bofh.it> <sYLJU-3mz-17@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 12/01/2017 12:24, Måns Rullgård wrote:
> Marc Gonzalez writes:
>
>>> So far we have a claim that a cast to a void * may somehow be different
>>> to a cast to a different pointer, if used as function argument, and that
>>> the behavior with such a cast may be undefined. In other words, you claim
>>> that a function implemented as, say,
>>>
>>> void func(int *var) {}
>>>
>>> might result in undefined behavior if some header file declares it as
>>>
>>> void func(void *);
>>>
>>> and it is called as
>>>
>>> int var;
>>>
>>> func(&var);
>>>
>>> That seems really far fetched to me.
>>
>> Thanks for giving me an opportunity to play the language lawyer :-)
>>
>> C99 6.3.2.3 sub-clause 8 states:
>>
>> "A pointer to a function of one type may be converted to a pointer to
>> a function of another type and back again; the result shall compare
>> equal to the original pointer. If a converted pointer is used to call
>> a function whose type is not compatible with the pointed-to type, the
>> behavior is undefined."
>>
>> So, the behavior is undefined, not when you cast clk_disable_unprepare,
>> but when clk_disable_unprepare is later called through the devres->action
>> function pointer.
>
> Only if the function types are incompatible. C99 6.7.5.3 subclause 15:
>
> For two function types to be compatible, both shall specify compatible
> return types. Moreover, the parameter type lists, if both are
> present, shall agree in the number of parameters and in use of the
> ellipsis terminator; corresponding parameters shall have compatible
> types.
>
> The question then is whether pointer to void and pointer to struct clk
> are compatible types.
6.2.7 Compatible type and composite type
sub-clause 1
"Two types have compatible type if their types are the same. Additional rules for
determining whether two types are compatible are described in 6.7.2 for type specifiers,
in 6.7.3 for type qualifiers, and in 6.7.5 for declarators."
6.7.5.1 Pointer declarators
sub-clause 2
"For two pointer types to be compatible, both shall be identically qualified and both shall
be pointers to compatible types."
I don't think void and struct clk are compatible types.
AFAIU, conversion and compatibility are two separate subjects.
Regards.
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[PATCH 00/62] watchdog: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 22/62] watchdog: imx2_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 12/62] watchdog: da9055_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 04/62] watchdog: atlas7_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 15/62] watchdog: davinci_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 29/62] watchdog: max77620_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 08/62] watchdog: bcm_kona_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 30/62] watchdog: mena21_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
Re: [PATCH 30/62] watchdog: mena21_wdt: Convert to use device managed functions and other improvements Johannes Thumshirn <morbidrsa@gmail.com> - 2017-01-13 09:10 +0100
[PATCH 02/62] watchdog: aspeed_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
Re: [PATCH 02/62] watchdog: aspeed_wdt: Convert to use device managed functions Joel Stanley <joel@jms.id.au> - 2017-01-11 06:20 +0100
[PATCH 03/62] watchdog: at91sam9_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 25/62] watchdog: kempld_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 09/62] watchdog: cadence_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:40 +0100
[PATCH 05/62] watchdog: bcm2835_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:50 +0100
Re: [PATCH 05/62] watchdog: bcm2835_wdt: Convert to use device managed functions and other improvements Eric Anholt <eric@anholt.net> - 2017-01-14 07:30 +0100
[PATCH 21/62] watchdog: imgpdc_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:50 +0100
[PATCH 19/62] watchdog: gpio_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:50 +0100
[PATCH 10/62] watchdog: coh901327_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 00:50 +0100
Re: [PATCH 10/62] watchdog: coh901327_wdt: Convert to use device managed functions Linus Walleij <linus.walleij@linaro.org> - 2017-01-11 16:50 +0100
[PATCH 38/62] watchdog: nic7018_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 49/62] watchdog: sama5d4_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 40/62] watchdog: omap_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 39/62] watchdog: of_xilinx_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 36/62] watchdog: mt7621_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 42/62] watchdog: pic32-dmt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 35/62] watchdog: mpc8xxx_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 46/62] watchdog: renesas_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 32/62] watchdog: meson_gxbb_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
Re: [PATCH 32/62] watchdog: meson_gxbb_wdt: Convert to use device managed functions and other improvements Neil Armstrong <narmstrong@baylibre.com> - 2017-01-11 09:50 +0100
Re: [PATCH 32/62] watchdog: meson_gxbb_wdt: Convert to use device managed functions and other improvements Kevin Hilman <khilman@baylibre.com> - 2017-01-11 19:50 +0100
[PATCH 41/62] watchdog: orion_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 34/62] watchdog: moxart_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 47/62] watchdog: retu_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 37/62] watchdog: mtk_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 50/62] watchdog: sbsa_gwdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 43/62] watchdog: pic32-wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 44/62] watchdog: pnx4008_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
Re: [PATCH 44/62] watchdog: pnx4008_wdt: Convert to use device managed functions Vladimir Zapolskiy <vz@mleia.com> - 2017-01-12 01:20 +0100
[PATCH 45/62] watchdog: qcom-wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 31/62] watchdog: menf21bmc_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 48/62] watchdog: rt2880_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 51/62] watchdog: shwdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
[PATCH 33/62] watchdog: meson_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 01:50 +0100
Re: [PATCH 33/62] watchdog: meson_wdt: Convert to use device managed functions and other improvements Kevin Hilman <khilman@baylibre.com> - 2017-01-11 19:50 +0100
[PATCH 53/62] watchdog: st_lpc_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:10 +0100
[PATCH 52/62] watchdog: sirfsoc_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:10 +0100
[PATCH 55/62] watchdog: sunxi_wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:10 +0100
Re: [PATCH 55/62] watchdog: sunxi_wdt: Convert to use device managed functions and other improvements Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-01-11 13:20 +0100
[PATCH 57/62] watchdog: tegra_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
[PATCH 61/62] watchdog: ux500_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
[PATCH 60/62] watchdog: txx9wdt: Convert to use device managed functions and other improvements Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
[PATCH 59/62] watchdog: twl4030_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
[PATCH 62/62] watchdog: wm831x_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
Re: [PATCH 62/62] watchdog: wm831x_wdt: Convert to use device managed functions Charles Keepax <ckeepax@opensource.wolfsonmicro.com> - 2017-01-12 11:30 +0100
[PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-01-11 10:10 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 12:00 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-01-11 13:40 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 15:30 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Måns Rullgård <mans@mansr.com> - 2017-01-11 15:50 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-01-11 16:30 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 19:00 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-01-12 10:50 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2017-01-12 11:00 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Måns Rullgård <mans@mansr.com> - 2017-01-12 12:30 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Marc Gonzalez <marc_gonzalez@sigmadesigns.com> - 2017-01-12 13:20 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Uwe Kleine-König <u.kleine-koenig@pengutronix.de> - 2017-01-11 15:40 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> - 2017-01-11 16:00 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 18:30 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-13 06:20 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-01-12 01:20 +0100
Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-12 02:40 +0100
[PATCH 54/62] watchdog: stmp3xxx_rtc_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
[PATCH 58/62] watchdog: ts4800_wdt: Convert to use device managed functions Guenter Roeck <linux@roeck-us.net> - 2017-01-11 03:20 +0100
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