Hi Linus,
On 2018-12-05 13:47, Linus Walleij wrote:
> When we get a nonexeclusive GPIO descriptor using managed
> resources, we should only add it to the list of managed
> resources once: on the first user. Augment the
> devm_gpiod_get_index() and devm_gpiod_get_from_of_node()
> calls to account for this by checking if the descriptor
> is already resource managed before we proceed to allocate
> a new resource management struct.
>
> Cc: Mark Brown <[email protected]>
> Cc: Bartosz Golaszewski <[email protected]>
> Cc: Marek Szyprowski <[email protected]>
> Fixes: b0ce7b29bfcd ("regulator/gpio: Allow nonexclusive GPIO access")
> Reported-by: Marek Szyprowski <[email protected]>
> Signed-off-by: Linus Walleij <[email protected]>
> ---
> ChangeLog v1->v3:
> - New patch.
> - This fix is in response to an issue Marek saw in the fixups
> for resource-managed GPIO descriptors used with ena_gpiod
> in the regulator subsystem.
> - I first thought to apply it to the GPIO tree directly, but
> since it is not a regression it is better to put it into
> the regulator tree with the rest of the patches.
> ---
> drivers/gpio/gpiolib-devres.c | 50 ++++++++++++++++++++++++++---------
> 1 file changed, 38 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c
> index 01959369360b..a57e968025a8 100644
> --- a/drivers/gpio/gpiolib-devres.c
> +++ b/drivers/gpio/gpiolib-devres.c
> @@ -98,15 +98,28 @@ struct gpio_desc *__must_check
> devm_gpiod_get_index(struct device *dev,
> struct gpio_desc **dr;
> struct gpio_desc *desc;
>
> + desc = gpiod_get_index(dev, con_id, idx, flags);
> + if (IS_ERR(desc))
> + return desc;
> +
> + /*
> + * For non-exclusive GPIO descriptors, check if this descriptor is
> + * already under resource management by this device.
> + */
> + if (flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
> + struct devres *dres;
> +
> + dres = devres_find(dev, devm_gpiod_release,
> + devm_gpiod_match, desc);
devres_find(dev, devm_gpiod_release, devm_gpiod_match, &desc);
> + if (dres)
> + return desc;
> + }
> +
> dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
> GFP_KERNEL);
> - if (!dr)
> + if (!dr) {
> + gpiod_put(desc);
> return ERR_PTR(-ENOMEM);
> -
> - desc = gpiod_get_index(dev, con_id, idx, flags);
> - if (IS_ERR(desc)) {
> - devres_free(dr);
> - return desc;
> }
>
> *dr = desc;
> @@ -140,15 +153,28 @@ struct gpio_desc *devm_gpiod_get_from_of_node(struct
> device *dev,
> struct gpio_desc **dr;
> struct gpio_desc *desc;
>
> + desc = gpiod_get_from_of_node(node, propname, index, dflags, label);
> + if (IS_ERR(desc))
> + return desc;
> +
> + /*
> + * For non-exclusive GPIO descriptors, check if this descriptor is
> + * already under resource management by this device.
> + */
> + if (dflags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
> + struct devres *dres;
> +
> + dres = devres_find(dev, devm_gpiod_release,
> + devm_gpiod_match, desc);
devres_find(dev, devm_gpiod_release, devm_gpiod_match, &desc);
> + if (dres)
> + return desc;
> + }
> +
> dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
> GFP_KERNEL);
> - if (!dr)
> + if (!dr) {
> + gpiod_put(desc);
> return ERR_PTR(-ENOMEM);
> -
> - desc = gpiod_get_from_of_node(node, propname, index, dflags, label);
> - if (IS_ERR(desc)) {
> - devres_free(dr);
> - return desc;
> }
>
> *dr = desc;
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
