Struct gpio_device now provides a revocable provider to the underlying struct gpio_chip. Leverage revocable for accessing the struct gpio_chip.
Signed-off-by: Tzung-Bi Shih <[email protected]> --- v3: - Change revocable API usages accordingly. v2: https://lore.kernel.org/all/[email protected] - Separate from v1(a) for excluding gpio_chip_guard and combine v1(b). v1(a): - https://lore.kernel.org/all/[email protected] v1(b): - https://lore.kernel.org/all/[email protected] drivers/gpio/gpiolib.c | 60 +++++++++++++----------------------------- 1 file changed, 18 insertions(+), 42 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 34f2665a9311..2ba78add3417 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -338,7 +338,10 @@ EXPORT_SYMBOL(gpio_device_get_label); */ struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev) { - return rcu_dereference_check(gdev->chip, 1); + struct gpio_chip *gc; + + revocable_try_access_with(gdev->chip_rp, gc); + return gc; } EXPORT_SYMBOL_GPL(gpio_device_get_chip); @@ -556,9 +559,7 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name) list_for_each_entry_srcu(gdev, &gpio_devices, list, srcu_read_lock_held(&gpio_devices_srcu)) { - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); if (!gc) continue; @@ -972,9 +973,7 @@ static void gpiochip_setup_devs(void) list_for_each_entry_srcu(gdev, &gpio_devices, list, srcu_read_lock_held(&gpio_devices_srcu)) { - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); if (!gc) { dev_err(&gdev->dev, "Underlying GPIO chip is gone\n"); continue; @@ -1378,11 +1377,11 @@ struct gpio_device *gpio_device_find(const void *data, if (!device_is_registered(&gdev->dev)) continue; - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); + if (!gc) + continue; - if (gc && match(gc, data)) + if (match(gc, data)) return gpio_device_get(gdev); } @@ -3310,18 +3309,10 @@ static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *des static int gpiod_get_raw_value_commit(const struct gpio_desc *desc) { - struct gpio_device *gdev; struct gpio_chip *gc; int value; - /* FIXME Unable to use gpio_chip_guard due to const desc. */ - gdev = desc->gdev; - - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(desc->gdev->chip_rp, gc); value = gpio_chip_get_value(gc, desc); value = value < 0 ? value : !!value; @@ -3360,9 +3351,10 @@ static int gpio_chip_get_multiple(struct gpio_chip *gc, /* The 'other' chip must be protected with its GPIO device's SRCU. */ static bool gpio_device_chip_cmp(struct gpio_device *gdev, struct gpio_chip *gc) { - guard(srcu)(&gdev->srcu); + struct gpio_chip *chip; - return gc == srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, chip); + return chip ? chip == gc : false; } int gpiod_get_array_value_complex(bool raw, bool can_sleep, @@ -3385,11 +3377,7 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep, if (!can_sleep) WARN_ON(array_info->gdev->can_sleep); - guard(srcu)(&array_info->gdev->srcu); - gc = srcu_dereference(array_info->gdev->chip, - &array_info->gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(array_info->gdev->chip_rp, gc); ret = gpio_chip_get_multiple(gc, array_info->get_mask, value_bitmap); @@ -3726,11 +3714,7 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, return -EPERM; } - guard(srcu)(&array_info->gdev->srcu); - gc = srcu_dereference(array_info->gdev->chip, - &array_info->gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(array_info->gdev->chip_rp, gc); if (!raw && !bitmap_empty(array_info->invert_mask, array_size)) bitmap_xor(value_bitmap, value_bitmap, @@ -4024,7 +4008,6 @@ EXPORT_SYMBOL_GPL(gpiod_is_shared); */ int gpiod_to_irq(const struct gpio_desc *desc) { - struct gpio_device *gdev; struct gpio_chip *gc; int offset; int ret; @@ -4033,12 +4016,7 @@ int gpiod_to_irq(const struct gpio_desc *desc) if (ret <= 0) return -EINVAL; - gdev = desc->gdev; - /* FIXME Cannot use gpio_chip_guard due to const desc. */ - guard(srcu)(&gdev->srcu); - gc = srcu_dereference(gdev->chip, &gdev->srcu); - if (!gc) - return -ENODEV; + revocable_try_access_or_return(desc->gdev->chip_rp, gc); offset = gpiod_hwgpio(desc); if (gc->to_irq) { @@ -5413,9 +5391,7 @@ static int gpiolib_seq_show(struct seq_file *s, void *v) if (priv->newline) seq_putc(s, '\n'); - guard(srcu)(&gdev->srcu); - - gc = srcu_dereference(gdev->chip, &gdev->srcu); + revocable_try_access_with(gdev->chip_rp, gc); if (!gc) { seq_printf(s, "%s: (dangling chip)\n", dev_name(&gdev->dev)); return 0; -- 2.53.0.310.g728cabbaf7-goog
