On 11/15/23 2:21 AM, Yunsheng Lin wrote: > On 2023/11/14 21:16, Jason Gunthorpe wrote: >> On Tue, Nov 14, 2023 at 04:21:26AM -0800, Mina Almasry wrote: >> >>> Actually because you put the 'strtuct page for devmem' in >>> skb->bv_frag, the net stack will grab the 'struct page' for devmem >>> using skb_frag_page() then call things like page_address(), kmap, >>> get_page, put_page, etc, etc, etc. >> >> Yikes, please no. If net has its own struct page look alike it has to >> stay entirely inside net. A non-mm owned struct page should not be >> passed into mm calls. It is just way too hacky to be seriously >> considered :( > > Yes, that is something this patchset is trying to do, defining its own > struct page look alike for page pool to support devmem. > Networking needs to be able to move away from struct page references. The devmem and host memory for Rx use cases do not need to be page based.
