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

Eric Auger
2015-10-22T11:46:27Z

On 10/22/2015 12:19 PM, Arnd Bergmann wrote:
> 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.
OK
>
>> +
>>
>> 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().
I should have added those assignments in next patch actually. This
latter moves the vfio_platform_put_reset call in the release function.

Best Regards

Eric
>
> Arnd
>