On 5/2/25 9:25 PM, Mina Almasry wrote: > On Fri, May 2, 2025 at 4:51 AM Paolo Abeni <pab...@redhat.com> wrote: >> >> On 5/2/25 1:47 PM, Paolo Abeni wrote: >>> On 4/29/25 5:26 AM, Mina Almasry wrote: >>>> Augment dmabuf binding to be able to handle TX. Additional to all the RX >>>> binding, we also create tx_vec needed for the TX path. >>>> >>>> Provide API for sendmsg to be able to send dmabufs bound to this device: >>>> >>>> - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. >>>> - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. >>>> >>>> Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY >>>> implementation, while disabling instances where MSG_ZEROCOPY falls back >>>> to copying. >>>> >>>> We additionally pipe the binding down to the new >>>> zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems >>>> instead of the traditional page netmems. >>>> >>>> We also special case skb_frag_dma_map to return the dma-address of these >>>> dmabuf net_iovs instead of attempting to map pages. >>>> >>>> The TX path may release the dmabuf in a context where we cannot wait. >>>> This happens when the user unbinds a TX dmabuf while there are still >>>> references to its netmems in the TX path. In that case, the netmems will >>>> be put_netmem'd from a context where we can't unmap the dmabuf, Resolve >>>> this by making __net_devmem_dmabuf_binding_free schedule_work'd. >>>> >>>> Based on work by Stanislav Fomichev <s...@fomichev.me>. A lot of the meat >>>> of the implementation came from devmem TCP RFC v1[1], which included the >>>> TX path, but Stan did all the rebasing on top of netmem/net_iov. >>>> >>>> Cc: Stanislav Fomichev <s...@fomichev.me> >>>> Signed-off-by: Kaiyuan Zhang <kaiyu...@google.com> >>>> Signed-off-by: Mina Almasry <almasrym...@google.com> >>>> Acked-by: Stanislav Fomichev <s...@fomichev.me> >>> >>> I'm sorry for the late feedback. A bunch of things I did not notice >>> before... >> >> The rest LGTM, > > Does this imply I should attach your Reviewed-by or Acked-by on follow > up submissions if any? I'm happy either way, just checking.
Should any other revision be required, please add my acked-by tag to all the patch except 4/9. Thanks, Paolo
