Re: [PATCH v2 5/6] vfio: platform: use list of registered reset function

Arnd Bergmann
2015-10-22T10:19:33Z

On Thursday 22 October 2015 11:42:01 Eric Auger wrote:
> Remove the static lookup table and use the dynamic list of registered
> reset functions instead. Also load the reset module through its alias.
> The reset struct module pointer is stored in vfio_platform_device.
>
> We also remove the useless struct device pointer parameter in
> vfio_platform_get_reset.
>
> This patch fixes the issue related to the usage of __symbol_get, which
> besides from being moot, prevented compilation with CONFIG_MODULES
> disabled.
>
> Also usage of MODULE_ALIAS makes possible to add a new reset module
> without needing to update the framework. This was suggested by Arnd.
>
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> Reported-by: Arnd Bergmann <arnd@arndb.de>

Looks good, just small style issues:

>
> - }
> + mutex_lock(&reset_lock);
> + list_for_each_entry(iter, &reset_list, link) {
> + if (!strcmp(iter->compat, compat) &&
> + try_module_get(iter->owner)) {
> + *module = iter->owner;
> + mutex_unlock(&reset_lock);
> + return iter->reset;
> }
> }
> +
> + mutex_unlock(&reset_lock);
> + return NULL;

Better use 'break' to have a single mutex_unlock and return statement.

> +
>
> static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
> {
> - if (vdev->reset)
> - symbol_put_addr(vdev->reset);
> + if (vdev->reset) {
> + module_put(vdev->reset_module);
> + vdev->reset_module = NULL;
> + vdev->reset = NULL;
> + }
> }

This gets called from the remove callback. No need to clear those
struct members immediately before the kfree().

Arnd