Re: [PATCH v3 06/11] s390: cio: Use driver_set_override() instead of open-coding

Vineeth Vijayan
2022-03-01T16:02:10Z

On 2/27/22 14:52, Krzysztof Kozlowski wrote:
> Use a helper for seting driver_override to reduce amount of duplicated
> code. Make the driver_override field const char, because it is not
> modified by the core and it matches other subsystems.
s/seting/setting/

Also could you please change the title to start with "s390/cio:"
instead of "s390 : cio"

Otherwise,

Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
> ---
> drivers/s390/cio/cio.h | 7 ++++++-
> drivers/s390/cio/css.c | 28 ++++------------------------
> 2 files changed, 10 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
> index 1cb9daf9c645..e110c10613e8 100644
> --- a/drivers/s390/cio/cio.h
> +++ b/drivers/s390/cio/cio.h
> @@ -103,7 +103,12 @@ struct subchannel {
> struct work_struct todo_work;
> struct schib_config config;
> u64 dma_mask;
> - char *driver_override; /* Driver name to force a match */
> + /*
> + * Driver name to force a match.
> + * Do not set directly, because core frees it.
> + * Use driver_set_override() to set or clear it.
> + */
As Bjorn Helgaas mentioned, please wrap this comment.
> + const char *driver_override;
> } __attribute__ ((aligned(8)));
>
> DECLARE_PER_CPU_ALIGNED(struct irb, cio_irb);
> diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
> index fa8293335077..913b6ddd040b 100644
> --- a/drivers/s390/cio/css.c
> +++ b/drivers/s390/cio/css.c
> @@ -338,31 +338,11 @@ static ssize_t driver_override_store(struct device *dev,
> const char *buf, size_t count)
> {
> struct subchannel *sch = to_subchannel(dev);
> - char *driver_override, *old, *cp;
> -
> - /* We need to keep extra room for a newline */
> - if (count >= (PAGE_SIZE - 1))
> - return -EINVAL;
> -
> - 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 = sch->driver_override;
> - if (strlen(driver_override)) {
> - sch->driver_override = driver_override;
> - } else {
> - kfree(driver_override);
> - sch->driver_override = NULL;
> - }
> - device_unlock(dev);
> + int ret;
>
> - kfree(old);
> + ret = driver_set_override(dev, &sch->driver_override, buf, count);
> + if (ret)
> + return ret;
>
> return count;
> }