Re: [EXT] Re: [PATCH v4 1/2] net: page_pool: export page_pool_stats definition

From: Andrew Lunn
Date: Tue Nov 15 2022 - 12:43:32 EST


> > I agree the API is broken, but i think there is a better fix.
> >
> > There should be a stub of page_pool_get_stats() for when
> > CONFIG_PAGE_POOL_STATS is disabled.
> >
> > Nothing actually dereferences struct page_pool_stats when you have this stub.
> > So it might be enough to simply have
> >
> > struct page_pool_stats{
> > };
> >
>
> As the structure is open when the CONFIG_PAGE_POOL_STATS is enabled, you can not
> prevent a user to access its members. The empty stub will still have problems in this
> kind of situations.

The users, i.e. the driver, has no need to access its members. The
members can change, new ones can be added, and it will not cause a
problem, given the way this API is defined. Ideally, page_pool_stats
would of been an opaque cookie, but that is not how it was
implemented :-(

Andrew