2022-02-24 01:06:10

by Bjorn Helgaas

[permalink] [raw]
Subject: Re: [PATCH v2 05/11] pci: use helper for safer setting of driver_override

In subject, to match drivers/pci/ convention, do something like:

PCI: Use driver_set_override() instead of open-coding

On Wed, Feb 23, 2022 at 08:13:04PM +0100, Krzysztof Kozlowski wrote:
> Use a helper for seting driver_override to reduce amount of duplicated
> code.

s/seting/setting/

> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> ---
> drivers/pci/pci-sysfs.c | 24 ++++--------------------
> 1 file changed, 4 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 602f0fb0b007..16a163d4623e 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -567,31 +567,15 @@ static ssize_t driver_override_store(struct device *dev,
> const char *buf, size_t count)
> {
> struct pci_dev *pdev = to_pci_dev(dev);
> - char *driver_override, *old, *cp;
> + int ret;
>
> /* We need to keep extra room for a newline */
> if (count >= (PAGE_SIZE - 1))
> return -EINVAL;

This check makes no sense in the new function. Michael alluded to
this as well.

> - driver_override = kstrndup(buf, count, GFP_KERNEL);
> - if (!driver_override)
> - return -ENOMEM;
> -
> - cp = strchr(driver_override, '\n');
> - if (cp)
> - *cp = '\0';
> -
> - device_lock(dev);
> - old = pdev->driver_override;
> - if (strlen(driver_override)) {
> - pdev->driver_override = driver_override;
> - } else {
> - kfree(driver_override);
> - pdev->driver_override = NULL;
> - }
> - device_unlock(dev);
> -
> - kfree(old);
> + ret = driver_set_override(dev, &pdev->driver_override, buf);
> + if (ret)
> + return ret;
>
> return count;
> }
> --
> 2.32.0
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


2022-02-24 08:14:12

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH v2 05/11] pci: use helper for safer setting of driver_override

On 23/02/2022 22:51, Bjorn Helgaas wrote:
> In subject, to match drivers/pci/ convention, do something like:
>
> PCI: Use driver_set_override() instead of open-coding
>
> On Wed, Feb 23, 2022 at 08:13:04PM +0100, Krzysztof Kozlowski wrote:
>> Use a helper for seting driver_override to reduce amount of duplicated
>> code.
>
> s/seting/setting/
>
>> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>> ---
>> drivers/pci/pci-sysfs.c | 24 ++++--------------------
>> 1 file changed, 4 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
>> index 602f0fb0b007..16a163d4623e 100644
>> --- a/drivers/pci/pci-sysfs.c
>> +++ b/drivers/pci/pci-sysfs.c
>> @@ -567,31 +567,15 @@ static ssize_t driver_override_store(struct device *dev,
>> const char *buf, size_t count)
>> {
>> struct pci_dev *pdev = to_pci_dev(dev);
>> - char *driver_override, *old, *cp;
>> + int ret;
>>
>> /* We need to keep extra room for a newline */
>> if (count >= (PAGE_SIZE - 1))
>> return -EINVAL;
>
> This check makes no sense in the new function. Michael alluded to
> this as well.

I am not sure if I got your comment properly. You mean here:
1. Move this check to driver_set_override()?
2. Remove the check entirely?

>
>> - driver_override = kstrndup(buf, count, GFP_KERNEL);
>> - if (!driver_override)
>> - return -ENOMEM;
>> -
>> - cp = strchr(driver_override, '\n');
>> - if (cp)
>> - *cp = '\0';
>> -
>> - device_lock(dev);
>> - old = pdev->driver_override;
>> - if (strlen(driver_override)) {
>> - pdev->driver_override = driver_override;
>> - } else {
>> - kfree(driver_override);
>> - pdev->driver_override = NULL;
>> - }
>> - device_unlock(dev);
>> -
>> - kfree(old);
>> + ret = driver_set_override(dev, &pdev->driver_override, buf);
>> + if (ret)
>> + return ret;
>>
>> return count;
>> }
>> --
>> 2.32.0
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> [email protected]
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


Best regards,
Krzysztof

2022-02-25 11:48:39

by Bjorn Helgaas

[permalink] [raw]
Subject: Re: [PATCH v2 05/11] pci: use helper for safer setting of driver_override

On Thu, Feb 24, 2022 at 08:49:15AM +0100, Krzysztof Kozlowski wrote:
> On 23/02/2022 22:51, Bjorn Helgaas wrote:
> > In subject, to match drivers/pci/ convention, do something like:
> >
> > PCI: Use driver_set_override() instead of open-coding
> >
> > On Wed, Feb 23, 2022 at 08:13:04PM +0100, Krzysztof Kozlowski wrote:
> >> Use a helper for seting driver_override to reduce amount of duplicated
> >> code.
> >> @@ -567,31 +567,15 @@ static ssize_t driver_override_store(struct device *dev,
> >> const char *buf, size_t count)
> >> {
> >> struct pci_dev *pdev = to_pci_dev(dev);
> >> - char *driver_override, *old, *cp;
> >> + int ret;
> >>
> >> /* We need to keep extra room for a newline */
> >> if (count >= (PAGE_SIZE - 1))
> >> return -EINVAL;
> >
> > This check makes no sense in the new function. Michael alluded to
> > this as well.
>
> I am not sure if I got your comment properly. You mean here:
> 1. Move this check to driver_set_override()?
> 2. Remove the check entirely?

I was mistaken about the purpose of the comment and the check. I
thought it had to do with *this* function, and this function doesn't
add a newline, and there's no obvious connection with PAGE_SIZE.

But looking closer, I think the "extra room for a newline" is really
to make sure that *driver_override_show()* can add a newline and have
it still fit within the PAGE_SIZE sysfs limit.

Most driver_override_*() functions have the same comment, so maybe
this was obvious to everybody except me :) I do see that spi.c adds
"when displaying value" at the end, which helps a lot.

Sorry for the wild goose chase.

> >> - driver_override = kstrndup(buf, count, GFP_KERNEL);
> >> - if (!driver_override)
> >> - return -ENOMEM;
> >> -
> >> - cp = strchr(driver_override, '\n');
> >> - if (cp)
> >> - *cp = '\0';
> >> -
> >> - device_lock(dev);
> >> - old = pdev->driver_override;
> >> - if (strlen(driver_override)) {
> >> - pdev->driver_override = driver_override;
> >> - } else {
> >> - kfree(driver_override);
> >> - pdev->driver_override = NULL;
> >> - }
> >> - device_unlock(dev);
> >> -
> >> - kfree(old);
> >> + ret = driver_set_override(dev, &pdev->driver_override, buf);
> >> + if (ret)
> >> + return ret;
> >>
> >> return count;
> >> }
> >> --
> >> 2.32.0
> >>
> >>
> >> _______________________________________________
> >> linux-arm-kernel mailing list
> >> [email protected]
> >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>
> Best regards,
> Krzysztof
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel