net: socionext: netsec: always grab descriptor lock

Always acquire tx descriptor spinlock even if a xdp program is not loaded
on the netsec device since ndo_xdp_xmit can run concurrently with
netsec_netdev_start_xmit and netsec_clean_tx_dring. This can happen
loading a xdp program on a different device (e.g virtio-net) and
xdp_do_redirect_map/xdp_do_redirect_slow can redirect to netsec even if
we do not have a xdp program on it.

Fixes: ba2b232108d3 ("net: netsec: add XDP support")
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
index 55db7fbd43cc3cfd112c31803e1318bda1555e05..f9e6744d8fd6ea0527a86271044d400788158a27 100644 (file)
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -282,7 +282,6 @@ struct netsec_desc_ring {
        void *vaddr;
        u16 head, tail;
        u16 xdp_xmit; /* netsec_xdp_xmit packets */
-       bool is_xdp;
        struct page_pool *page_pool;
        struct xdp_rxq_info xdp_rxq;
        spinlock_t lock; /* XDP tx queue locking */
@@ -634,8 +633,7 @@ static bool netsec_clean_tx_dring(struct netsec_priv *priv)
        unsigned int bytes;
        int cnt = 0;
 
-       if (dring->is_xdp)
-               spin_lock(&dring->lock);
+       spin_lock(&dring->lock);
 
        bytes = 0;
        entry = dring->vaddr + DESC_SZ * tail;
@@ -682,8 +680,8 @@ next:
                entry = dring->vaddr + DESC_SZ * tail;
                cnt++;
        }
-       if (dring->is_xdp)
-               spin_unlock(&dring->lock);
+
+       spin_unlock(&dring->lock);
 
        if (!cnt)
                return false;
@@ -799,9 +797,6 @@ static void netsec_set_tx_de(struct netsec_priv *priv,
        de->data_buf_addr_lw = lower_32_bits(desc->dma_addr);
        de->buf_len_info = (tx_ctrl->tcp_seg_len << 16) | desc->len;
        de->attr = attr;
-       /* under spin_lock if using XDP */
-       if (!dring->is_xdp)
-               dma_wmb();
 
        dring->desc[idx] = *desc;
        if (desc->buf_type == TYPE_NETSEC_SKB)
@@ -1123,12 +1118,10 @@ static netdev_tx_t netsec_netdev_start_xmit(struct sk_buff *skb,
        u16 tso_seg_len = 0;
        int filled;
 
-       if (dring->is_xdp)
-               spin_lock_bh(&dring->lock);
+       spin_lock_bh(&dring->lock);
        filled = netsec_desc_used(dring);
        if (netsec_check_stop_tx(priv, filled)) {
-               if (dring->is_xdp)
-                       spin_unlock_bh(&dring->lock);
+               spin_unlock_bh(&dring->lock);
                net_warn_ratelimited("%s %s Tx queue full\n",
                                     dev_name(priv->dev), ndev->name);
                return NETDEV_TX_BUSY;
@@ -1161,8 +1154,7 @@ static netdev_tx_t netsec_netdev_start_xmit(struct sk_buff *skb,
        tx_desc.dma_addr = dma_map_single(priv->dev, skb->data,
                                          skb_headlen(skb), DMA_TO_DEVICE);
        if (dma_mapping_error(priv->dev, tx_desc.dma_addr)) {
-               if (dring->is_xdp)
-                       spin_unlock_bh(&dring->lock);
+               spin_unlock_bh(&dring->lock);
                netif_err(priv, drv, priv->ndev,
                          "%s: DMA mapping failed\n", __func__);
                ndev->stats.tx_dropped++;
@@ -1177,8 +1169,7 @@ static netdev_tx_t netsec_netdev_start_xmit(struct sk_buff *skb,
        netdev_sent_queue(priv->ndev, skb->len);
 
        netsec_set_tx_de(priv, dring, &tx_ctrl, &tx_desc, skb);
-       if (dring->is_xdp)
-               spin_unlock_bh(&dring->lock);
+       spin_unlock_bh(&dring->lock);
        netsec_write(priv, NETSEC_REG_NRM_TX_PKTCNT, 1); /* submit another tx */
 
        return NETDEV_TX_OK;
@@ -1262,7 +1253,6 @@ err:
 static void netsec_setup_tx_dring(struct netsec_priv *priv)
 {
        struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_TX];
-       struct bpf_prog *xdp_prog = READ_ONCE(priv->xdp_prog);
        int i;
 
        for (i = 0; i < DESC_NUM; i++) {
@@ -1275,12 +1265,6 @@ static void netsec_setup_tx_dring(struct netsec_priv *priv)
                 */
                de->attr = 1U << NETSEC_TX_SHIFT_OWN_FIELD;
        }
-
-       if (xdp_prog)
-               dring->is_xdp = true;
-       else
-               dring->is_xdp = false;
-
 }
 
 static int netsec_setup_rx_dring(struct netsec_priv *priv)