net/mlx5e: Support bpf_xdp_adjust_head()

This patch adds bpf_xdp_adjust_head() support to mlx5e.

1. rx_headroom is added to struct mlx5e_rq.  It uses
   an existing 4 byte hole in the struct.
2. The adjusted data length is checked against
   MLX5E_XDP_MIN_INLINE and MLX5E_SW2HW_MTU(rq->netdev->mtu).
3. The macro MLX5E_SW2HW_MTU is moved from en_main.c to en.h.
   MLX5E_HW2SW_MTU is also moved to en.h for symmetric reason
   but it is not a must.

v2:
- Keep the xdp specific logic in mlx5e_xdp_handle()
- Update dma_len after the sanity checks in mlx5e_xmit_xdp_frame()

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index a473cea..0d9dd86 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -51,6 +51,9 @@
 
 #define MLX5_SET_CFG(p, f, v) MLX5_SET(create_flow_group_in, p, f, v)
 
+#define MLX5E_HW2SW_MTU(hwmtu) ((hwmtu) - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN))
+#define MLX5E_SW2HW_MTU(swmtu) ((swmtu) + (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN))
+
 #define MLX5E_MAX_NUM_TC       8
 
 #define MLX5E_PARAMS_MINIMUM_LOG_SQ_SIZE                0x6
@@ -369,6 +372,7 @@ struct mlx5e_rq {
 
        unsigned long          state;
        int                    ix;
+       u16                    rx_headroom;
 
        struct mlx5e_rx_am     am; /* Adaptive Moderation */
        struct bpf_prog       *xdp_prog;

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index f74ba73..aba3691 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -343,9 +343,6 @@ static void mlx5e_disable_async_events(struct mlx5e_priv *priv)
        synchronize_irq(mlx5_get_msix_vec(priv->mdev, MLX5_EQ_VEC_ASYNC));
 }
 
-#define MLX5E_HW2SW_MTU(hwmtu) (hwmtu - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN))
-#define MLX5E_SW2HW_MTU(swmtu) (swmtu + (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN))
-
 static inline int mlx5e_get_wqe_mtt_sz(void)
 {
        /* UMR copies MTTs in units of MLX5_UMR_MTT_ALIGNMENT bytes.
@@ -534,9 +531,13 @@ static int mlx5e_create_rq(struct mlx5e_channel *c,
                goto err_rq_wq_destroy;
        }
 
-       rq->buff.map_dir = DMA_FROM_DEVICE;
-       if (rq->xdp_prog)
+       if (rq->xdp_prog) {
                rq->buff.map_dir = DMA_BIDIRECTIONAL;
+               rq->rx_headroom = XDP_PACKET_HEADROOM;
+       } else {
+               rq->buff.map_dir = DMA_FROM_DEVICE;
+               rq->rx_headroom = MLX5_RX_HEADROOM;
+       }
 
        switch (priv->params.rq_wq_type) {
        case MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ:
@@ -586,7 +587,7 @@ static int mlx5e_create_rq(struct mlx5e_channel *c,
                byte_count = rq->buff.wqe_sz;
 
                /* calc the required page order */
-               frag_sz = MLX5_RX_HEADROOM +
+               frag_sz = rq->rx_headroom +
                          byte_count /* packet data */ +
                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
                frag_sz = SKB_DATA_ALIGN(frag_sz);
@@ -3153,11 +3154,6 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)
        bool reset, was_opened;
        int i;
 
-       if (prog && prog->xdp_adjust_head) {
-               netdev_err(netdev, "Does not support bpf_xdp_adjust_head()\n");
-               return -EOPNOTSUPP;
-       }
-
        mutex_lock(&priv->state_lock);
 
        if ((netdev->features & NETIF_F_LRO) && prog) {

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 0e2fb3e..20f116f 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -264,7 +264,7 @@ int mlx5e_alloc_rx_wqe(struct mlx5e_rq *rq, struct mlx5e_rx_wqe *wqe, u16 ix)
        if (unlikely(mlx5e_page_alloc_mapped(rq, di)))
                return -ENOMEM;
 
-       wqe->data.addr = cpu_to_be64(di->addr + MLX5_RX_HEADROOM);
+       wqe->data.addr = cpu_to_be64(di->addr + rq->rx_headroom);
        return 0;
 }
 
@@ -646,8 +646,7 @@ static inline void mlx5e_xmit_xdp_doorbell(struct mlx5e_sq *sq)
 
 static inline void mlx5e_xmit_xdp_frame(struct mlx5e_rq *rq,
                                        struct mlx5e_dma_info *di,
-                                       unsigned int data_offset,
-                                       int len)
+                                       const struct xdp_buff *xdp)
 {
        struct mlx5e_sq          *sq   = &rq->channel->xdp_sq;
        struct mlx5_wq_cyc       *wq   = &sq->wq;
@@ -659,9 +658,16 @@ static inline void mlx5e_xmit_xdp_frame(struct mlx5e_rq *rq,
        struct mlx5_wqe_eth_seg  *eseg = &wqe->eth;
        struct mlx5_wqe_data_seg *dseg;
 
+       ptrdiff_t data_offset = xdp->data - xdp->data_hard_start;
        dma_addr_t dma_addr  = di->addr + data_offset + MLX5E_XDP_MIN_INLINE;
-       unsigned int dma_len = len - MLX5E_XDP_MIN_INLINE;
-       void *data           = page_address(di->page) + data_offset;
+       unsigned int dma_len = xdp->data_end - xdp->data;
+
+       if (unlikely(dma_len < MLX5E_XDP_MIN_INLINE ||
+                    MLX5E_SW2HW_MTU(rq->netdev->mtu) < dma_len)) {
+               rq->stats.xdp_drop++;
+               mlx5e_page_release(rq, di, true);
+               return;
+       }
 
        if (unlikely(!mlx5e_sq_has_room_for(sq, MLX5E_XDP_TX_WQEBBS))) {
                if (sq->db.xdp.doorbell) {
@@ -674,13 +680,14 @@ static inline void mlx5e_xmit_xdp_frame(struct mlx5e_rq *rq,
                return;
        }
 
+       dma_len -= MLX5E_XDP_MIN_INLINE;
        dma_sync_single_for_device(sq->pdev, dma_addr, dma_len,
                                   PCI_DMA_TODEVICE);
 
        memset(wqe, 0, sizeof(*wqe));
 
        /* copy the inline part */
-       memcpy(eseg->inline_hdr_start, data, MLX5E_XDP_MIN_INLINE);
+       memcpy(eseg->inline_hdr_start, xdp->data, MLX5E_XDP_MIN_INLINE);
        eseg->inline_hdr_sz = cpu_to_be16(MLX5E_XDP_MIN_INLINE);
 
        dseg = (struct mlx5_wqe_data_seg *)cseg + (MLX5E_XDP_TX_DS_COUNT - 1);
@@ -703,25 +710,29 @@ static inline void mlx5e_xmit_xdp_frame(struct mlx5e_rq *rq,
 }
 
 /* returns true if packet was consumed by xdp */
-static inline bool mlx5e_xdp_handle(struct mlx5e_rq *rq,
-                                   const struct bpf_prog *prog,
-                                   struct mlx5e_dma_info *di,
-                                   void *data, u16 len)
+static inline int mlx5e_xdp_handle(struct mlx5e_rq *rq,
+                                  struct mlx5e_dma_info *di,
+                                  void *va, u16 *rx_headroom, u32 *len)
 {
+       const struct bpf_prog *prog = READ_ONCE(rq->xdp_prog);
        struct xdp_buff xdp;
        u32 act;
 
        if (!prog)
                return false;
 
-       xdp.data = data;
-       xdp.data_end = xdp.data + len;
+       xdp.data = va + *rx_headroom;
+       xdp.data_end = xdp.data + *len;
+       xdp.data_hard_start = va;
+
        act = bpf_prog_run_xdp(prog, &xdp);
        switch (act) {
        case XDP_PASS:
+               *rx_headroom = xdp.data - xdp.data_hard_start;
+               *len = xdp.data_end - xdp.data;
                return false;
        case XDP_TX:
-               mlx5e_xmit_xdp_frame(rq, di, MLX5_RX_HEADROOM, len);
+               mlx5e_xmit_xdp_frame(rq, di, &xdp);
                return true;
        default:
                bpf_warn_invalid_xdp_action(act);
@@ -740,15 +751,16 @@ struct sk_buff *skb_from_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
        struct mlx5e_dma_info *di;
        struct sk_buff *skb;
        void *va, *data;
+       u16 rx_headroom = rq->rx_headroom;
        bool consumed;
 
        di             = &rq->dma_info[wqe_counter];
        va             = page_address(di->page);
-       data           = va + MLX5_RX_HEADROOM;
+       data           = va + rx_headroom;
 
        dma_sync_single_range_for_cpu(rq->pdev,
                                      di->addr,
-                                     MLX5_RX_HEADROOM,
+                                     rx_headroom,
                                      rq->buff.wqe_sz,
                                      DMA_FROM_DEVICE);
        prefetch(data);
@@ -760,8 +772,7 @@ struct sk_buff *skb_from_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
        }
 
        rcu_read_lock();
-       consumed = mlx5e_xdp_handle(rq, READ_ONCE(rq->xdp_prog), di, data,
-                                   cqe_bcnt);
+       consumed = mlx5e_xdp_handle(rq, di, va, &rx_headroom, &cqe_bcnt);
        rcu_read_unlock();
        if (consumed)
                return NULL; /* page/packet was consumed by XDP */
@@ -777,7 +788,7 @@ struct sk_buff *skb_from_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
        page_ref_inc(di->page);
        mlx5e_page_release(rq, di, true);
 
-       skb_reserve(skb, MLX5_RX_HEADROOM);
+       skb_reserve(skb, rx_headroom);
        skb_put(skb, cqe_bcnt);
 
        return skb;