On Wed, 13 Dec 2017 12:20:01 +0100, Jesper Dangaard Brouer wrote:
> Driver hook points for xdp_rxq_info:
> * init+reg: nfp_net_rx_ring_alloc
> * unreg : nfp_net_rx_ring_free
>
> In struct nfp_net_rx_ring moved member @size into a hole on 64-bit.
> Thus, the size remaines the same after adding member @xdp_rxq.
>
> Cc: oss-driv...@netronome.com
> Cc: Jakub Kicinski <jakub.kicin...@netronome.com>
> Cc: Simon Horman <simon.hor...@netronome.com>
> Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
> diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net.h
> b/drivers/net/ethernet/netronome/nfp/nfp_net.h
> index 3801c52098d5..0e564cfabe7e 100644
> --- a/drivers/net/ethernet/netronome/nfp/nfp_net.h
> +++ b/drivers/net/ethernet/netronome/nfp/nfp_net.h
> @@ -47,6 +47,7 @@
> #include <linux/netdevice.h>
> #include <linux/pci.h>
> #include <linux/io-64-nonatomic-hi-lo.h>
> +#include <net/xdp.h>
>
> #include "nfp_net_ctrl.h"
>
> @@ -350,6 +351,7 @@ struct nfp_net_rx_buf {
> * @rxds: Virtual address of FL/RX ring in host memory
> * @dma: DMA address of the FL/RX ring
> * @size: Size, in bytes, of the FL/RX ring (needed to free)
> + * @xdp_rxq: RX-ring info avail for XDP
> */
> struct nfp_net_rx_ring {
> struct nfp_net_r_vector *r_vec;
> @@ -361,13 +363,14 @@ struct nfp_net_rx_ring {
> u32 idx;
>
> int fl_qcidx;
> + unsigned int size;
> u8 __iomem *qcp_fl;
>
> struct nfp_net_rx_buf *rxbufs;
> struct nfp_net_rx_desc *rxds;
>
> dma_addr_t dma;
> - unsigned int size;
> + struct xdp_rxq_info xdp_rxq;
> } ____cacheline_aligned;
The @size member is not in the hole on purpose. IIRC all the members
up to @dma are in the first cacheline. All things which are not needed
on the fast path are after @dma. IOW @size is not used on the fast
path and the hole is for fast path stuff :)
> /**
> diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> index ad3e9f6a61e5..6474aecd0451 100644
> --- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
> @@ -2252,6 +2253,7 @@ static void nfp_net_rx_ring_free(struct nfp_net_rx_ring
> *rx_ring)
> struct nfp_net_r_vector *r_vec = rx_ring->r_vec;
> struct nfp_net_dp *dp = &r_vec->nfp_net->dp;
>
> + xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
> kfree(rx_ring->rxbufs);
>
> if (rx_ring->rxds)
> @@ -2277,6 +2279,12 @@ nfp_net_rx_ring_alloc(struct nfp_net_dp *dp, struct
> nfp_net_rx_ring *rx_ring)
> {
> int sz;
>
> + /* XDP RX-queue info */
> + xdp_rxq_info_init(&rx_ring->xdp_rxq);
> + rx_ring->xdp_rxq.dev = dp->netdev;
> + rx_ring->xdp_rxq.queue_index = rx_ring->idx;
> + xdp_rxq_info_reg(&rx_ring->xdp_rxq);
> +
> rx_ring->cnt = dp->rxd_cnt;
> rx_ring->size = sizeof(*rx_ring->rxds) * rx_ring->cnt;
> rx_ring->rxds = dma_zalloc_coherent(dp->dev, rx_ring->size,
The nfp driver implements the prepare/commit for reallocating rings.
I don't think it matters now, but there can be 2 sets of rings with the
same ID allocated during reconfiguration (see nfp_net_ring_reconfig()).
Maybe place the register/unregister in nfp_net_open_stack() and
nfp_net_close_stack() respectively?
Perhaps that won't be necessary, only cleaner :) I'm not sure how is
the redirect between drivers intended to work WRT freeing rings and
unloading drivers while packets fly...
