W dniu 12 maja 2011 23:41 użytkownik Mahesh Bandewar
<[email protected]> napisał:
> On Wed, May 11, 2011 at 10:50 PM, Michał Mirosław <[email protected]> wrote:
>> W dniu 12 maja 2011 01:11 użytkownik Mahesh Bandewar
>> <[email protected]> napisał:
>>> On Wed, May 11, 2011 at 12:15 PM, Michał Mirosław <[email protected]> wrote:
>>>> If e1000_set_loopback() fails, this should set dev->features to passed
>>>> features (but keeping NETIF_F_LOOPBACK unchanged in dev->features) to
>>>> keep the state consistent.
>>> set_features() can return the return code of set_loopback() instead of
>>> 0; this way the consistency will be maintained.
>> Only as long as NETIF_F_LOOPBACK is the only bit set in hw_features.
>> netdev_update_features() can't really know which features were changed
>> and which failed when ndo_set_features callback returns non-zero.
> This is more of an API shortcoming. Callback will have to revert
> changes made (rollback) before returning non-zero value to keep it
> consistent.

It might just update dev->features to match instead of rollback. It
could also start some recovery process that eventually calls
netdev_update_features() again to try the change again.

IOW, the information what changes failed are returned implicitly in
modified dev->features. When callback returns 0,
netdev_update_features() assumes that all were set correctly and
updates dev->features itself.

Best Regards,
Michał Mirosław

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