On Tue, Nov 07, 2017 at 12:13:44PM +0100, Thierry Reding wrote: > On Mon, Nov 06, 2017 at 05:13:33PM -0600, Grygorii Strashko wrote: > > On 11/06/2017 05:18 AM, Thierry Reding wrote: > > > On Fri, Nov 03, 2017 at 05:30:30PM -0500, Grygorii Strashko wrote: [...] > > >> @@ -312,8 +321,29 @@ struct gpio_chip { > > >> extern const char *gpiochip_is_requested(struct gpio_chip *chip, > > >> unsigned offset); > > >> > > >> +extern int gpiochip_add_data_key(struct gpio_chip *chip, void *data, > > >> + struct *irq_lock_key); > > >> +#ifdef CONFIG_LOCKDEP > > >> +/* > > >> + * Lockdep requires that each irqchip instance be created with a > > >> + * unique key so as to avoid unnecessary warnings. This upfront > > >> + * boilerplate static inlines provides such a key for each > > >> + * unique instance which is created now from inside gpiochip_add_data_key(). > > >> + */ > > >> +static inline int gpiochip_add_data(struct gpio_chip *chip, void *data) > > >> +{ > > >> + static struct lock_class_key key; > > >> + > > >> + return gpiochip_add_data_key(chip, data, key); > > >> +} > > > > > > This looks like a neat improvement, but I think it can be done in a > > > follow-up to remove the boilerplate in drivers. > > > > Can't agree here - it better to be considered now. > > Now only two GPIO drivers define lock_class_key: > > ./drivers/gpio/gpio-bcm-kona.c:static struct lock_class_key gpio_lock_class; > > ./drivers/gpio/gpio-brcmstb.c:static struct lock_class_key brcmstb_gpio_irq_lock_class; > > > > and these drivers do not use gpioirq framework (your tegra driver will be the third). > > > > So, if proposed changes will be applied all drivers switched to use it will need to define > > its own lock_class_key again and it will be step back. > > I think this would be a minor, mostly mechanical refactoring to do as > follow-up. But since you feel very strongly about it, I'll add that into > the series. After implementing this, I'm having second thoughts. We've got a bunch of drivers calling gpiochip_add_data() that never register an IRQ chip but which will each add a struct lock_class_key after this change, and it will never be used. Now, struct lock_class_key is only 8 bytes big, so maybe this isn't a big deal, but it still seems like a waste. Thierry
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