On Wed, Dec 20, 2023 at 01:45:01PM -0800, Mina Almasry wrote: > Add the netmem_ref type, an abstraction for network memory. > > To add support for new memory types to the net stack, we must first > abstract the current memory type. Currently parts of the net stack > use struct page directly: > > - page_pool > - drivers > - skb_frag_t > > Originally the plan was to reuse struct page* for the new memory types, > and to set the LSB on the page* to indicate it's not really a page. > However, for compiler type checking we need to introduce a new type. > > netmem_ref is introduced to abstract the underlying memory type. Currently > it's a no-op abstraction that is always a struct page underneath. In > parallel there is an undergoing effort to add support for devmem to the > net stack: > > https://lore.kernel.org/netdev/20231208005250.2910004-1-almasrymina@xxxxxxxxxx/ > > Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> > > --- > > v3: > > - Modify struct netmem from a union of struct page + new types to an opaque > netmem_ref type. I went with: > > +typedef void *__bitwise netmem_ref; > > rather than this that Jakub recommended: > > +typedef unsigned long __bitwise netmem_ref; > > Because with the latter the compiler issues warnings to cast NULL to > netmem_ref. I hope that's ok. > Can you share what the warning was? You might just need __force attribute. However you might need this __force a lot. I wonder if you can just follow struct encoded_page example verbatim here.
