On Thu, 2021-06-17 at 22:18 +0800, Xuan Zhuo wrote:
> On Thu, 17 Jun 2021 15:09:48 +0200, Maciej Fijalkowski <
> maciej.fijalkowski@xxxxxxxxx> wrote:
> > On Tue, Jun 15, 2021 at 11:37:19AM +0800, Xuan Zhuo wrote:
> > > When each driver supports xsk rx, if the received buff returns
> > > XDP_PASS
> > > after run xdp prog, it must construct skb based on xdp. This
> > > patch
> > > extracts this logic into a public function xdp_construct_skb().
> > >
> > > There is a bug in the original logic. When constructing skb, we
> > > should
> > > copy the meta information to skb and then use __skb_pull() to
> > > correct
> > > the data.
> > >
> > > Fixes: 0a714186d3c0f ("i40e: add AF_XDP zero-copy Rx support")
> > > Fixes: 2d4238f556972 ("ice: Add support for AF_XDP")
> > > Fixes: bba2556efad66 ("net: stmmac: Enable RX via AF_XDP zero-
> > > copy")
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > > ---
> > >
> > > This patch depends on the previous patch:
> > > [PATCH net] ixgbe: xsk: fix for metasize when construct skb
> > > by xdp_buff
> >
> > That doesn't make much sense if you ask me, I'd rather squash the
> > patch
> > mentioned above to this one.
>
> I saw that the previous patch was put into net-queue, I don't know
> whether to
> merge it into the current patch, so I posted this patch, I hope
> someone can tell
> me how to deal with this situation.
The previous patch was to the Intel Wired LAN tree since it was just
ixgbe driver. I will drop this from Intel Wired LAN tree since it
hasn't been submitted to netdev and with these changes it makes more
sense as a single squashed patch.
> > Also, I wanted to introduce such function to the kernel for a long
> > time
> > but I always head in the back of my head mlx5's AF_XDP ZC
> > implementation
> > which I'm not sure if it can adjust to something like Intel drivers
> > are
> > doing.
>
> I have this question too.
>
> Thanks
>
> > Maxim? :)
> >
> > > drivers/net/ethernet/intel/i40e/i40e_xsk.c | 16 +---------
> > > drivers/net/ethernet/intel/ice/ice_xsk.c | 12 +-------
> > > drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 14 +--------
> > > .../net/ethernet/stmicro/stmmac/stmmac_main.c | 23 +----------
> > > ---
> > > include/net/xdp.h | 30
> > > +++++++++++++++++++
> > > 5 files changed, 34 insertions(+), 61 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > > b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > > index 68f177a86403..81b0f44eedda 100644
> > > --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > > +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> > > @@ -246,23 +246,9 @@ bool i40e_alloc_rx_buffers_zc(struct
> > > i40e_ring *rx_ring, u16 count)
> > > static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring
> > > *rx_ring,
> > > struct xdp_buff *xdp)
> > > {
> > > - unsigned int metasize = xdp->data - xdp->data_meta;
> > > - unsigned int datasize = xdp->data_end - xdp->data;
> > > struct sk_buff *skb;
> > >
> > > - /* allocate a skb to store the frags */
> > > - skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
> > > - xdp->data_end - xdp->data_hard_start,
> > > - GFP_ATOMIC | __GFP_NOWARN);
> > > - if (unlikely(!skb))
> > > - goto out;
> > > -
> > > - skb_reserve(skb, xdp->data - xdp->data_hard_start);
> > > - memcpy(__skb_put(skb, datasize), xdp->data, datasize);
> > > - if (metasize)
> > > - skb_metadata_set(skb, metasize);
> > > -
> > > -out:
> > > + skb = xdp_construct_skb(xdp, &rx_ring->q_vector->napi);
> > > xsk_buff_free(xdp);
> > > return skb;
> > > }
> > > diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c
> > > b/drivers/net/ethernet/intel/ice/ice_xsk.c
> > > index a1f89ea3c2bd..f95e1adcebda 100644
> > > --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> > > +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> > > @@ -430,22 +430,12 @@ static void ice_bump_ntc(struct ice_ring
> > > *rx_ring)
> > > static struct sk_buff *
> > > ice_construct_skb_zc(struct ice_ring *rx_ring, struct ice_rx_buf
> > > *rx_buf)
> > > {
> > > - unsigned int metasize = rx_buf->xdp->data - rx_buf->xdp-
> > > >data_meta;
> > > - unsigned int datasize = rx_buf->xdp->data_end - rx_buf->xdp-
> > > >data;
> > > - unsigned int datasize_hard = rx_buf->xdp->data_end -
> > > - rx_buf->xdp->data_hard_start;
> > > struct sk_buff *skb;
> > >
> > > - skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize_hard,
> > > - GFP_ATOMIC | __GFP_NOWARN);
> > > + skb = xdp_construct_skb(rx_buf->xdp, &rx_ring->q_vector->napi);
> > > if (unlikely(!skb))
> > > return NULL;
> > >
> > > - skb_reserve(skb, rx_buf->xdp->data - rx_buf->xdp-
> > > >data_hard_start);
> > > - memcpy(__skb_put(skb, datasize), rx_buf->xdp->data, datasize);
> > > - if (metasize)
> > > - skb_metadata_set(skb, metasize);
> > > -
> > > xsk_buff_free(rx_buf->xdp);
> > > rx_buf->xdp = NULL;
> > > return skb;
> > > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> > > b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> > > index ee88107fa57a..123945832c96 100644
> > > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> > > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> > > @@ -203,24 +203,12 @@ bool ixgbe_alloc_rx_buffers_zc(struct
> > > ixgbe_ring *rx_ring, u16 count)
> > > static struct sk_buff *ixgbe_construct_skb_zc(struct ixgbe_ring
> > > *rx_ring,
> > > struct ixgbe_rx_buffer
> > > *bi)
> > > {
> > > - unsigned int metasize = bi->xdp->data - bi->xdp->data_meta;
> > > - unsigned int datasize = bi->xdp->data_end - bi->xdp->data_meta;
> > > struct sk_buff *skb;
> > >
> > > - /* allocate a skb to store the frags */
> > > - skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
> > > - bi->xdp->data_end - bi->xdp-
> > > >data_hard_start,
> > > - GFP_ATOMIC | __GFP_NOWARN);
> > > + skb = xdp_construct_skb(bi->xdp, &rx_ring->q_vector->napi);
> > > if (unlikely(!skb))
> > > return NULL;
> > >
> > > - skb_reserve(skb, bi->xdp->data_meta - bi->xdp-
> > > >data_hard_start);
> > > - memcpy(__skb_put(skb, datasize), bi->xdp->data_meta, datasize);
> > > - if (metasize) {
> > > - __skb_pull(skb, metasize);
> > > - skb_metadata_set(skb, metasize);
> > > - }
> > > -
> > > xsk_buff_free(bi->xdp);
> > > bi->xdp = NULL;
> > > return skb;
> > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > > b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > > index c87202cbd3d6..143ac1edb876 100644
> > > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > > @@ -4729,27 +4729,6 @@ static void stmmac_finalize_xdp_rx(struct
> > > stmmac_priv *priv,
> > > xdp_do_flush();
> > > }
> > >
> > > -static struct sk_buff *stmmac_construct_skb_zc(struct
> > > stmmac_channel *ch,
> > > - struct xdp_buff *xdp)
> > > -{
> > > - unsigned int metasize = xdp->data - xdp->data_meta;
> > > - unsigned int datasize = xdp->data_end - xdp->data;
> > > - struct sk_buff *skb;
> > > -
> > > - skb = __napi_alloc_skb(&ch->rxtx_napi,
> > > - xdp->data_end - xdp->data_hard_start,
> > > - GFP_ATOMIC | __GFP_NOWARN);
> > > - if (unlikely(!skb))
> > > - return NULL;
> > > -
> > > - skb_reserve(skb, xdp->data - xdp->data_hard_start);
> > > - memcpy(__skb_put(skb, datasize), xdp->data, datasize);
> > > - if (metasize)
> > > - skb_metadata_set(skb, metasize);
> > > -
> > > - return skb;
> > > -}
> > > -
> > > static void stmmac_dispatch_skb_zc(struct stmmac_priv *priv, u32
> > > queue,
> > > struct dma_desc *p, struct dma_desc
> > > *np,
> > > struct xdp_buff *xdp)
> > > @@ -4761,7 +4740,7 @@ static void stmmac_dispatch_skb_zc(struct
> > > stmmac_priv *priv, u32 queue,
> > > struct sk_buff *skb;
> > > u32 hash;
> > >
> > > - skb = stmmac_construct_skb_zc(ch, xdp);
> > > + skb = xdp_construct_skb(xdp, &ch->rxtx_napi);
> > > if (!skb) {
> > > priv->dev->stats.rx_dropped++;
> > > return;
> > > diff --git a/include/net/xdp.h b/include/net/xdp.h
> > > index a5bc214a49d9..561e21eaf718 100644
> > > --- a/include/net/xdp.h
> > > +++ b/include/net/xdp.h
> > > @@ -95,6 +95,36 @@ xdp_prepare_buff(struct xdp_buff *xdp,
> > > unsigned char *hard_start,
> > > xdp->data_meta = meta_valid ? data : data + 1;
> > > }
> > >
> > > +static __always_inline struct sk_buff *
> > > +xdp_construct_skb(struct xdp_buff *xdp, struct napi_struct
> > > *napi)
> > > +{
> > > + unsigned int metasize;
> > > + unsigned int datasize;
> > > + unsigned int headroom;
> > > + struct sk_buff *skb;
> > > + unsigned int len;
> > > +
> > > + /* this include metasize */
> > > + datasize = xdp->data_end - xdp->data_meta;
> > > + metasize = xdp->data - xdp->data_meta;
> > > + headroom = xdp->data_meta - xdp->data_hard_start;
> > > + len = xdp->data_end - xdp->data_hard_start;
> > > +
> > > + /* allocate a skb to store the frags */
> > > + skb = __napi_alloc_skb(napi, len, GFP_ATOMIC | __GFP_NOWARN);
> > > + if (unlikely(!skb))
> > > + return NULL;
> > > +
> > > + skb_reserve(skb, headroom);
> > > + memcpy(__skb_put(skb, datasize), xdp->data_meta, datasize);
> > > + if (metasize) {
> > > + __skb_pull(skb, metasize);
> > > + skb_metadata_set(skb, metasize);
> > > + }
> > > +
> > > + return skb;
> > > +}
> > > +
> > > /* Reserve memory area at end-of data area.
> > > *
> > > * This macro reserves tailroom in the XDP buffer by limiting
> > > the
> > > --
> > > 2.31.0
> > >
