RE: [PATCH v3 04/11] hv: Use driver_set_override() instead of open-coding

Michael Kelley (LINUX)
2022-02-27T15:53:07Z

From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Sent: Sunday, February 27, 2022 5:52 AM
>
> 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.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
> ---
> drivers/hv/vmbus_drv.c | 28 ++++------------------------
> include/linux/hyperv.h | 7 ++++++-
> 2 files changed, 10 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 12a2b37e87f3..a0ff4139c3d2 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -575,31 +575,11 @@ static ssize_t driver_override_store(struct device *dev,
> const char *buf, size_t count)
> {
> struct hv_device *hv_dev = device_to_hv_device(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 = hv_dev->driver_override;
> - if (strlen(driver_override)) {
> - hv_dev->driver_override = driver_override;
> - } else {
> - kfree(driver_override);
> - hv_dev->driver_override = NULL;
> - }
> - device_unlock(dev);
> + int ret;
>
> - kfree(old);
> + ret = driver_set_override(dev, &hv_dev->driver_override, buf, count);
> + if (ret)
> + return ret;
>
> return count;
> }
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index fe2e0179ed51..beea11874be2 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1257,7 +1257,12 @@ struct hv_device {
> u16 device_id;
>
> struct device device;
> - 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.
> + */
> + const char *driver_override;
>
> struct vmbus_channel *channel;
> struct kset *channels_kset;
> --
> 2.32.0

Reviewed-by: Michael Kelley <mikelley@microsoft.com>