6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx> commit 81570d6a7ad37033c7895811551a5a9023706eda upstream. During the locking rework in GPIOLIB, we omitted one important use-case, namely: setting and getting values for GPIO descriptor arrays with array_info present. This patch does two things: first it makes struct gpio_array store the address of the underlying GPIO device and not chip. Next: it protects the chip with SRCU from removal in gpiod_get_array_value_complex() and gpiod_set_array_value_complex(). Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20250215095655.23152-1-brgl@xxxxxxxx Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpio/gpiolib.c | 48 +++++++++++++++++++++++++++++++++--------------- drivers/gpio/gpiolib.h | 4 ++-- 2 files changed, 35 insertions(+), 17 deletions(-) --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -3082,6 +3082,8 @@ static int gpiod_get_raw_value_commit(co static int gpio_chip_get_multiple(struct gpio_chip *gc, unsigned long *mask, unsigned long *bits) { + lockdep_assert_held(&gc->gpiodev->srcu); + if (gc->get_multiple) return gc->get_multiple(gc, mask, bits); if (gc->get) { @@ -3112,6 +3114,7 @@ int gpiod_get_array_value_complex(bool r struct gpio_array *array_info, unsigned long *value_bitmap) { + struct gpio_chip *gc; int ret, i = 0; /* @@ -3123,10 +3126,15 @@ int gpiod_get_array_value_complex(bool r array_size <= array_info->size && (void *)array_info == desc_array + array_info->size) { if (!can_sleep) - WARN_ON(array_info->chip->can_sleep); + WARN_ON(array_info->gdev->can_sleep); - ret = gpio_chip_get_multiple(array_info->chip, - array_info->get_mask, + guard(srcu)(&array_info->gdev->srcu); + gc = srcu_dereference(array_info->gdev->chip, + &array_info->gdev->srcu); + if (!gc) + return -ENODEV; + + ret = gpio_chip_get_multiple(gc, array_info->get_mask, value_bitmap); if (ret) return ret; @@ -3407,6 +3415,8 @@ static void gpiod_set_raw_value_commit(s static void gpio_chip_set_multiple(struct gpio_chip *gc, unsigned long *mask, unsigned long *bits) { + lockdep_assert_held(&gc->gpiodev->srcu); + if (gc->set_multiple) { gc->set_multiple(gc, mask, bits); } else { @@ -3424,6 +3434,7 @@ int gpiod_set_array_value_complex(bool r struct gpio_array *array_info, unsigned long *value_bitmap) { + struct gpio_chip *gc; int i = 0; /* @@ -3435,14 +3446,19 @@ int gpiod_set_array_value_complex(bool r array_size <= array_info->size && (void *)array_info == desc_array + array_info->size) { if (!can_sleep) - WARN_ON(array_info->chip->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; if (!raw && !bitmap_empty(array_info->invert_mask, array_size)) bitmap_xor(value_bitmap, value_bitmap, array_info->invert_mask, array_size); - gpio_chip_set_multiple(array_info->chip, array_info->set_mask, - value_bitmap); + gpio_chip_set_multiple(gc, array_info->set_mask, value_bitmap); i = find_first_zero_bit(array_info->set_mask, array_size); if (i == array_size) @@ -4698,9 +4714,10 @@ struct gpio_descs *__must_check gpiod_ge { struct gpio_desc *desc; struct gpio_descs *descs; + struct gpio_device *gdev; struct gpio_array *array_info = NULL; - struct gpio_chip *gc; int count, bitmap_size; + unsigned long dflags; size_t descs_size; count = gpiod_count(dev, con_id); @@ -4721,7 +4738,7 @@ struct gpio_descs *__must_check gpiod_ge descs->desc[descs->ndescs] = desc; - gc = gpiod_to_chip(desc); + gdev = gpiod_to_gpio_device(desc); /* * If pin hardware number of array member 0 is also 0, select * its chip as a candidate for fast bitmap processing path. @@ -4729,8 +4746,8 @@ struct gpio_descs *__must_check gpiod_ge if (descs->ndescs == 0 && gpio_chip_hwgpio(desc) == 0) { struct gpio_descs *array; - bitmap_size = BITS_TO_LONGS(gc->ngpio > count ? - gc->ngpio : count); + bitmap_size = BITS_TO_LONGS(gdev->ngpio > count ? + gdev->ngpio : count); array = krealloc(descs, descs_size + struct_size(array_info, invert_mask, 3 * bitmap_size), @@ -4750,7 +4767,7 @@ struct gpio_descs *__must_check gpiod_ge array_info->desc = descs->desc; array_info->size = count; - array_info->chip = gc; + array_info->gdev = gdev; bitmap_set(array_info->get_mask, descs->ndescs, count - descs->ndescs); bitmap_set(array_info->set_mask, descs->ndescs, @@ -4763,7 +4780,7 @@ struct gpio_descs *__must_check gpiod_ge continue; /* Unmark array members which don't belong to the 'fast' chip */ - if (array_info->chip != gc) { + if (array_info->gdev != gdev) { __clear_bit(descs->ndescs, array_info->get_mask); __clear_bit(descs->ndescs, array_info->set_mask); } @@ -4786,9 +4803,10 @@ struct gpio_descs *__must_check gpiod_ge array_info->set_mask); } } else { + dflags = READ_ONCE(desc->flags); /* Exclude open drain or open source from fast output */ - if (gpiochip_line_is_open_drain(gc, descs->ndescs) || - gpiochip_line_is_open_source(gc, descs->ndescs)) + if (test_bit(FLAG_OPEN_DRAIN, &dflags) || + test_bit(FLAG_OPEN_SOURCE, &dflags)) __clear_bit(descs->ndescs, array_info->set_mask); /* Identify 'fast' pins which require invertion */ @@ -4800,7 +4818,7 @@ struct gpio_descs *__must_check gpiod_ge if (array_info) dev_dbg(dev, "GPIO array info: chip=%s, size=%d, get_mask=%lx, set_mask=%lx, invert_mask=%lx\n", - array_info->chip->label, array_info->size, + array_info->gdev->label, array_info->size, *array_info->get_mask, *array_info->set_mask, *array_info->invert_mask); return descs; --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -110,7 +110,7 @@ extern const char *const gpio_suffixes[] * * @desc: Array of pointers to the GPIO descriptors * @size: Number of elements in desc - * @chip: Parent GPIO chip + * @gdev: Parent GPIO device * @get_mask: Get mask used in fastpath * @set_mask: Set mask used in fastpath * @invert_mask: Invert mask used in fastpath @@ -122,7 +122,7 @@ extern const char *const gpio_suffixes[] struct gpio_array { struct gpio_desc **desc; unsigned int size; - struct gpio_chip *chip; + struct gpio_device *gdev; unsigned long *get_mask; unsigned long *set_mask; unsigned long invert_mask[];
