mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-09 16:07:17 -04:00
Code Issues Packages Projects Releases Wiki Activity

gpio: don't set label from irq helpers

Browse Source 
We will soon serialize access to the descriptor label using SRCU. The
write-side of the protection will require calling synchronize_srcu()
which must not be called from atomic context. We have two irq helpers:
gpiochip_lock_as_irq() and gpiochip_unlock_as_irq() that set the label
if the GPIO is not requested but is being used as interrupt. They are
called with a spinlock held from the interrupt subsystem.

They must not do it if we are to use SRCU so instead let's move the
special corner case to a dedicated getter.

Don't actually set the label to "interrupt" in the above case but rather
use the newly added gpiod_get_label() helper to hide the logic that
atomically checks the descriptor flags and returns the address of a
static "interrupt" string.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Bartosz Golaszewski
2024-01-29 10:23:27 +01:00
parent d23dc4a9a8
commit ccfb6ff4f6
1 changed files with 8 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/gpio/gpiolib.c
View File

@@ -107,7 +107,14 @@ static bool gpiolib_initialized;
const char *gpiod_get_label(struct gpio_desc *desc)
{
return desc->label;
unsigned long flags;
flags = READ_ONCE(desc->flags);
if (test_bit(FLAG_USED_AS_IRQ, &flags) &&
!test_bit(FLAG_REQUESTED, &flags))
return "interrupt";
return test_bit(FLAG_REQUESTED, &flags) ? desc->label : NULL;
}
static inline void desc_set_label(struct gpio_desc *d, const char *label)
@@ -3599,14 +3606,6 @@ int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset)
set_bit(FLAG_USED_AS_IRQ, &desc->flags);
set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
/*
* If the consumer has not set up a label (such as when the
* IRQ is referenced from .to_irq()) we set up a label here
* so it is clear this is used as an interrupt.
*/
if (!desc->label)
desc_set_label(desc, "interrupt");
return 0;
}
EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
@@ -3629,10 +3628,6 @@ void gpiochip_unlock_as_irq(struct gpio_chip *gc, unsigned int offset)
clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
clear_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
/* If we only had this marking, erase it */
if (desc->label && !strcmp(desc->label, "interrupt"))
desc_set_label(desc, NULL);
}
EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);