* [PATCH v3 1/2] gpiolib: improve coding style for local variables
@ 2021-11-24 12:28 Bartosz Golaszewski
2021-11-24 12:28 ` [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code Bartosz Golaszewski
2021-11-24 14:35 ` [PATCH v3 1/2] gpiolib: improve coding style for local variables Andy Shevchenko
0 siblings, 2 replies; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-11-24 12:28 UTC (permalink / raw)
To: Linus Walleij, Andy Shevchenko, Johan Hovold
Cc: linux-gpio, linux-kernel, Bartosz Golaszewski
Drop unneeded whitespaces and put the variables of the same type
together for consistency with the rest of the code.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
v1 -> v2:
- keep initializations on separate lines
drivers/gpio/gpiolib.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index abfbf546d159..ede8b8a7aa18 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -594,11 +594,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
struct lock_class_key *request_key)
{
struct fwnode_handle *fwnode = gc->parent ? dev_fwnode(gc->parent) : NULL;
- unsigned long flags;
- int ret = 0;
- unsigned i;
- int base = gc->base;
struct gpio_device *gdev;
+ unsigned long flags;
+ int base = gc->base;
+ unsigned int i;
+ int ret = 0;
/*
* First: allocate and populate the internal stat container, and
--
2.25.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
2021-11-24 12:28 [PATCH v3 1/2] gpiolib: improve coding style for local variables Bartosz Golaszewski
@ 2021-11-24 12:28 ` Bartosz Golaszewski
2021-11-24 14:46 ` Andy Shevchenko
2021-11-24 14:35 ` [PATCH v3 1/2] gpiolib: improve coding style for local variables Andy Shevchenko
1 sibling, 1 reply; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-11-24 12:28 UTC (permalink / raw)
To: Linus Walleij, Andy Shevchenko, Johan Hovold
Cc: linux-gpio, linux-kernel, Bartosz Golaszewski
Several drivers read the 'ngpios' device property on their own, but
since it's defined as a standard GPIO property in the device tree bindings
anyway, it's a good candidate for generalization. If the driver didn't
set its gc->ngpio, try to read the 'ngpios' property from the GPIO
device's firmware node before bailing out.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
v1 -> v2:
- use device_property_read_u32() instead of fwnode_property_read_u32()
- reverse the error check logic
v2 -> v3:
- don't shadow errors other than -ENODATA in device_property_read_u32()
drivers/gpio/gpiolib.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ede8b8a7aa18..f79fd2551cf7 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -599,6 +599,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
int base = gc->base;
unsigned int i;
int ret = 0;
+ u32 ngpios;
/*
* First: allocate and populate the internal stat container, and
@@ -647,9 +648,17 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
}
if (gc->ngpio == 0) {
- chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
- ret = -EINVAL;
- goto err_free_descs;
+ ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
+ if (ret) {
+ if (ret == -ENODATA) {
+ chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
+ ret = -EINVAL;
+ }
+
+ goto err_free_descs;
+ }
+
+ gc->ngpio = ngpios;
}
if (gc->ngpio > FASTPATH_NGPIO)
--
2.25.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v3 1/2] gpiolib: improve coding style for local variables
2021-11-24 12:28 [PATCH v3 1/2] gpiolib: improve coding style for local variables Bartosz Golaszewski
2021-11-24 12:28 ` [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code Bartosz Golaszewski
@ 2021-11-24 14:35 ` Andy Shevchenko
2021-11-24 14:42 ` Bartosz Golaszewski
1 sibling, 1 reply; 9+ messages in thread
From: Andy Shevchenko @ 2021-11-24 14:35 UTC (permalink / raw)
To: Bartosz Golaszewski; +Cc: Linus Walleij, Johan Hovold, linux-gpio, linux-kernel
On Wed, Nov 24, 2021 at 01:28:49PM +0100, Bartosz Golaszewski wrote:
> Drop unneeded whitespaces and put the variables of the same type
> together for consistency with the rest of the code.
I thought I gave my tag, nevermind, here we are
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> v1 -> v2:
> - keep initializations on separate lines
>
> drivers/gpio/gpiolib.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index abfbf546d159..ede8b8a7aa18 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -594,11 +594,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> struct lock_class_key *request_key)
> {
> struct fwnode_handle *fwnode = gc->parent ? dev_fwnode(gc->parent) : NULL;
> - unsigned long flags;
> - int ret = 0;
> - unsigned i;
> - int base = gc->base;
> struct gpio_device *gdev;
> + unsigned long flags;
> + int base = gc->base;
> + unsigned int i;
> + int ret = 0;
>
> /*
> * First: allocate and populate the internal stat container, and
> --
> 2.25.1
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 1/2] gpiolib: improve coding style for local variables
2021-11-24 14:35 ` [PATCH v3 1/2] gpiolib: improve coding style for local variables Andy Shevchenko
@ 2021-11-24 14:42 ` Bartosz Golaszewski
0 siblings, 0 replies; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-11-24 14:42 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linus Walleij, Johan Hovold, open list:GPIO SUBSYSTEM,
Linux Kernel Mailing List
On Wed, Nov 24, 2021 at 3:35 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Nov 24, 2021 at 01:28:49PM +0100, Bartosz Golaszewski wrote:
> > Drop unneeded whitespaces and put the variables of the same type
> > together for consistency with the rest of the code.
>
> I thought I gave my tag, nevermind, here we are
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>
I removed it because the patch changed. Thanks!
Bart
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
2021-11-24 12:28 ` [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code Bartosz Golaszewski
@ 2021-11-24 14:46 ` Andy Shevchenko
2021-11-24 14:49 ` Andy Shevchenko
2021-11-25 10:10 ` Bartosz Golaszewski
0 siblings, 2 replies; 9+ messages in thread
From: Andy Shevchenko @ 2021-11-24 14:46 UTC (permalink / raw)
To: Bartosz Golaszewski; +Cc: Linus Walleij, Johan Hovold, linux-gpio, linux-kernel
On Wed, Nov 24, 2021 at 01:28:50PM +0100, Bartosz Golaszewski wrote:
> Several drivers read the 'ngpios' device property on their own, but
> since it's defined as a standard GPIO property in the device tree bindings
> anyway, it's a good candidate for generalization. If the driver didn't
> set its gc->ngpio, try to read the 'ngpios' property from the GPIO
> device's firmware node before bailing out.
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> v1 -> v2:
> - use device_property_read_u32() instead of fwnode_property_read_u32()
> - reverse the error check logic
>
> v2 -> v3:
> - don't shadow errors other than -ENODATA in device_property_read_u32()
>
> drivers/gpio/gpiolib.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index ede8b8a7aa18..f79fd2551cf7 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -599,6 +599,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> int base = gc->base;
> unsigned int i;
> int ret = 0;
> + u32 ngpios;
>
> /*
> * First: allocate and populate the internal stat container, and
> @@ -647,9 +648,17 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> }
> if (gc->ngpio == 0) {
> - chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> - ret = -EINVAL;
> - goto err_free_descs;
> + ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> + if (ret) {
> + if (ret == -ENODATA) {
> + chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> + ret = -EINVAL;
> + }
> +
> + goto err_free_descs;
> + }
And if the property returns 0 in ngpios?
What about the modified suggestion from previous version:
if (gc->ngpio == 0) {
ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
/*
* -ENODATA means that there is no property found and
* we want to issue the error message to the user. Besides
* that, we want to return different error code to state
* that supplied value is not valid.
*/
if (ret == -ENODATA)
ngpios = 0;
else if (ret)
return ret;
gc->ngpio = ngpios;
}
if (gc->ngpio == 0) {
chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
ret = -EINVAL;
goto err_free_descs;
}
?
> + gc->ngpio = ngpios;
> }
>
> if (gc->ngpio > FASTPATH_NGPIO)
> --
> 2.25.1
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
2021-11-24 14:46 ` Andy Shevchenko
@ 2021-11-24 14:49 ` Andy Shevchenko
2021-11-25 10:10 ` Bartosz Golaszewski
1 sibling, 0 replies; 9+ messages in thread
From: Andy Shevchenko @ 2021-11-24 14:49 UTC (permalink / raw)
To: Bartosz Golaszewski; +Cc: Linus Walleij, Johan Hovold, linux-gpio, linux-kernel
On Wed, Nov 24, 2021 at 04:46:58PM +0200, Andy Shevchenko wrote:
> On Wed, Nov 24, 2021 at 01:28:50PM +0100, Bartosz Golaszewski wrote:
> > Several drivers read the 'ngpios' device property on their own, but
> > since it's defined as a standard GPIO property in the device tree bindings
> > anyway, it's a good candidate for generalization. If the driver didn't
> > set its gc->ngpio, try to read the 'ngpios' property from the GPIO
> > device's firmware node before bailing out.
...
> What about the modified suggestion from previous version:
>
> if (gc->ngpio == 0) {
> ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> /*
> * -ENODATA means that there is no property found and
> * we want to issue the error message to the user. Besides
> * that, we want to return different error code to state
> * that supplied value is not valid.
> */
> if (ret == -ENODATA)
> ngpios = 0;
> else if (ret)
> return ret;
>
> gc->ngpio = ngpios;
> }
>
> if (gc->ngpio == 0) {
> chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> ret = -EINVAL;
> goto err_free_descs;
> }
>
> ?
If you okay to go with this code,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
2021-11-24 14:46 ` Andy Shevchenko
2021-11-24 14:49 ` Andy Shevchenko
@ 2021-11-25 10:10 ` Bartosz Golaszewski
2021-11-25 11:18 ` Andy Shevchenko
1 sibling, 1 reply; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-11-25 10:10 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linus Walleij, Johan Hovold, open list:GPIO SUBSYSTEM,
Linux Kernel Mailing List
On Wed, Nov 24, 2021 at 3:47 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Nov 24, 2021 at 01:28:50PM +0100, Bartosz Golaszewski wrote:
> > Several drivers read the 'ngpios' device property on their own, but
> > since it's defined as a standard GPIO property in the device tree bindings
> > anyway, it's a good candidate for generalization. If the driver didn't
> > set its gc->ngpio, try to read the 'ngpios' property from the GPIO
> > device's firmware node before bailing out.
>
> > Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> > ---
> > v1 -> v2:
> > - use device_property_read_u32() instead of fwnode_property_read_u32()
> > - reverse the error check logic
> >
> > v2 -> v3:
> > - don't shadow errors other than -ENODATA in device_property_read_u32()
> >
> > drivers/gpio/gpiolib.c | 15 ++++++++++++---
> > 1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index ede8b8a7aa18..f79fd2551cf7 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -599,6 +599,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> > int base = gc->base;
> > unsigned int i;
> > int ret = 0;
> > + u32 ngpios;
> >
> > /*
> > * First: allocate and populate the internal stat container, and
> > @@ -647,9 +648,17 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> > }
>
> > if (gc->ngpio == 0) {
> > - chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > - ret = -EINVAL;
> > - goto err_free_descs;
> > + ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> > + if (ret) {
> > + if (ret == -ENODATA) {
> > + chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > + ret = -EINVAL;
> > + }
> > +
> > + goto err_free_descs;
> > + }
>
> And if the property returns 0 in ngpios?
>
> What about the modified suggestion from previous version:
>
> if (gc->ngpio == 0) {
> ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
The comment is a good idea but other than that - it's overcomplicating things.
> if (ret == -ENODATA)
> ngpios = 0;
> else if (ret)
> return ret;
You still need to goto err_free_descs here.
>
> gc->ngpio = ngpios;
> }
>
> if (gc->ngpio == 0) {
Why check that again? We already know the driver set it to 0, we
checked it a couple lines before. If we can't get the setting from the
properties then it won't be non 0 here right?
> chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> ret = -EINVAL;
> goto err_free_descs;
> }
>
> ?
>
> > + gc->ngpio = ngpios;
> > }
> >
> > if (gc->ngpio > FASTPATH_NGPIO)
> > --
> > 2.25.1
> >
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
I suggest the following:
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ede8b8a7aa18..08c1e8fc0dfa 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -599,6 +599,7 @@ int gpiochip_add_data_with_key(struct gpio_chip
*gc, void *data,
int base = gc->base;
unsigned int i;
int ret = 0;
+ u32 ngpios;
/*
* First: allocate and populate the internal stat container, and
@@ -647,9 +648,23 @@ int gpiochip_add_data_with_key(struct gpio_chip
*gc, void *data,
}
if (gc->ngpio == 0) {
- chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
- ret = -EINVAL;
- goto err_free_descs;
+ /*
+ * If the driver didn't specify the number of GPIOs, try to
+ * get this value from the device properties as a fall-back.
+ */
+ ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
+ if (ret) {
+ /*
+ * -ENODATA means that there is no property found and
+ * we want to issue the error message to the user.
+ * Besides that, we want to return different error code
+ * to state that supplied value is not valid.
+ * */
+ if (ret == -ENODATA) {
+ chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
+ ret = -EINVAL;
+ }
+
+ goto err_free_descs;
+ }
+
+ gc->ngpio = ngpios;
}
if (gc->ngpio > FASTPATH_NGPIO)
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
2021-11-25 10:10 ` Bartosz Golaszewski
@ 2021-11-25 11:18 ` Andy Shevchenko
2021-12-02 10:26 ` Bartosz Golaszewski
0 siblings, 1 reply; 9+ messages in thread
From: Andy Shevchenko @ 2021-11-25 11:18 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: Linus Walleij, Johan Hovold, open list:GPIO SUBSYSTEM,
Linux Kernel Mailing List
On Thu, Nov 25, 2021 at 11:10:08AM +0100, Bartosz Golaszewski wrote:
> On Wed, Nov 24, 2021 at 3:47 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Wed, Nov 24, 2021 at 01:28:50PM +0100, Bartosz Golaszewski wrote:
...
> > > + ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> > > + if (ret) {
> > > + if (ret == -ENODATA) {
> > > + chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > > + ret = -EINVAL;
> > > + }
> > > +
> > > + goto err_free_descs;
> > > + }
> >
> > And if the property returns 0 in ngpios?
> >
> > What about the modified suggestion from previous version:
> >
> > if (gc->ngpio == 0) {
> > ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> The comment is a good idea but other than that - it's overcomplicating things.
I don't think so. It is plain and self-explaining each step. See at the end of
the message how.
> > if (ret == -ENODATA)
> > ngpios = 0;
> > else if (ret)
> > return ret;
> You still need to goto err_free_descs here.
Right, this doesn't affect the main point / logic here.
> > gc->ngpio = ngpios;
> > }
> >
> > if (gc->ngpio == 0) {
>
> Why check that again? We already know the driver set it to 0, we
> checked it a couple lines before. If we can't get the setting from the
> properties then it won't be non 0 here right?
No, it's not right. The check is needed to tell that properties supplied 0.
> > chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > ret = -EINVAL;
> > goto err_free_descs;
> > }
> >
> > ?
> >
> > > + gc->ngpio = ngpios;
> > > }
> > >
> > > if (gc->ngpio > FASTPATH_NGPIO)
> I suggest the following:
It's buggy as submitted version (I actually haven't found any difference in
the code, but comments).
You see, I propose less changes and straight forward logic:
1. Check if the supplied ->ngpio equal to 0
2. If so, try device properties
2.1. If there is no property found, make sure we a) don't use uninitialized
variable, b) we don't change ->ngpio, so it stays 0
2.2. If there is an error, return it as is to the caller
2.3. Assign ->ngpio by value from property (which very well may be 0!)
3. Check ->ngpio for 0 again, if so, issue a message and return -EINVAL to
the user.
We have three places where ->ngpio can be 0, all of them I covered.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
2021-11-25 11:18 ` Andy Shevchenko
@ 2021-12-02 10:26 ` Bartosz Golaszewski
0 siblings, 0 replies; 9+ messages in thread
From: Bartosz Golaszewski @ 2021-12-02 10:26 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Linus Walleij, Johan Hovold, open list:GPIO SUBSYSTEM,
Linux Kernel Mailing List
On Thu, Nov 25, 2021 at 12:18 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Thu, Nov 25, 2021 at 11:10:08AM +0100, Bartosz Golaszewski wrote:
> > On Wed, Nov 24, 2021 at 3:47 PM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > > On Wed, Nov 24, 2021 at 01:28:50PM +0100, Bartosz Golaszewski wrote:
>
> ...
>
> > > > + ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> > > > + if (ret) {
> > > > + if (ret == -ENODATA) {
> > > > + chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > > > + ret = -EINVAL;
> > > > + }
> > > > +
> > > > + goto err_free_descs;
> > > > + }
> > >
> > > And if the property returns 0 in ngpios?
> > >
> > > What about the modified suggestion from previous version:
> > >
> > > if (gc->ngpio == 0) {
> > > ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
>
> > The comment is a good idea but other than that - it's overcomplicating things.
>
> I don't think so. It is plain and self-explaining each step. See at the end of
> the message how.
>
> > > if (ret == -ENODATA)
> > > ngpios = 0;
> > > else if (ret)
> > > return ret;
>
> > You still need to goto err_free_descs here.
>
> Right, this doesn't affect the main point / logic here.
>
> > > gc->ngpio = ngpios;
> > > }
> > >
> > > if (gc->ngpio == 0) {
> >
> > Why check that again? We already know the driver set it to 0, we
> > checked it a couple lines before. If we can't get the setting from the
> > properties then it won't be non 0 here right?
>
> No, it's not right. The check is needed to tell that properties supplied 0.
>
> > > chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> > > ret = -EINVAL;
> > > goto err_free_descs;
> > > }
> > >
> > > ?
> > >
> > > > + gc->ngpio = ngpios;
> > > > }
> > > >
> > > > if (gc->ngpio > FASTPATH_NGPIO)
>
> > I suggest the following:
>
> It's buggy as submitted version (I actually haven't found any difference in
> the code, but comments).
>
> You see, I propose less changes and straight forward logic:
>
> 1. Check if the supplied ->ngpio equal to 0
> 2. If so, try device properties
> 2.1. If there is no property found, make sure we a) don't use uninitialized
> variable, b) we don't change ->ngpio, so it stays 0
> 2.2. If there is an error, return it as is to the caller
> 2.3. Assign ->ngpio by value from property (which very well may be 0!)
Ok, this is the thing I didn't realize, the property can indeed be 0
so your approach is correct.
Bart
> 3. Check ->ngpio for 0 again, if so, issue a message and return -EINVAL to
> the user.
>
> We have three places where ->ngpio can be 0, all of them I covered.
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-12-02 10:26 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-24 12:28 [PATCH v3 1/2] gpiolib: improve coding style for local variables Bartosz Golaszewski
2021-11-24 12:28 ` [PATCH v3 2/2] gpiolib: check the 'ngpios' property in core gpiolib code Bartosz Golaszewski
2021-11-24 14:46 ` Andy Shevchenko
2021-11-24 14:49 ` Andy Shevchenko
2021-11-25 10:10 ` Bartosz Golaszewski
2021-11-25 11:18 ` Andy Shevchenko
2021-12-02 10:26 ` Bartosz Golaszewski
2021-11-24 14:35 ` [PATCH v3 1/2] gpiolib: improve coding style for local variables Andy Shevchenko
2021-11-24 14:42 ` Bartosz Golaszewski
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).