On Tue, Mar 5, 2024, at 21:00, Mina Almasry wrote:
On Tue, Mar 5, 2024 at 1:05 AM Arnd Bergmann arnd@arndb.de wrote:
On Tue, Mar 5, 2024, at 03:01, Mina Almasry wrote:
A key goal of this patch series is that the kernel does not try to parse the skb frags that reside in the dma-buf for that precise reason. This is achieved using patch "net: add support for skbs with unreadable frags" which disables the kernel touching the payload in these skbs, and "tcp: RX path for devmem TCP" which implements a uapi where the kernel hands the data in the dmabuf to the userspace via a cmsg that gives the user a pointer to the data in the dmabuf (offset + size).
So really AFACT the only restriction here is that the NIC should be able to DMA into the dmabuf that we're attaching, and dma_buf_attach() fails in this scenario so we're covered there.
Ok, makes sense. Thanks for the clarification.
Arnd