[PATCH net-next 09/11] net: enetc: optimize the allocation of tx_bdr

[Wei Fang]

From: Clark Wang <xiaoning.wang@xxxxxxx>

There is a situation where num_tx_rings cannot be divided by
bdr_int_num. For example, num_tx_rings is 8 and bdr_int_num
is 3. According to the previous logic, this results in two
tx_bdr corresponding memories not being allocated, so when
sending packets to tx BD ring 6 or 7, wild pointers will be
accessed. Of course, this issue does not exist for LS1028A,
because its num_tx_rings is 8, and bdr_int_num is either 1
or 2. So there is no situation where it cannot be divided.
However, there is a risk for the upcoming i.MX95, so the
allocation of tx_bdr is optimized to ensure that each tx_bdr
can be allocated to the corresponding memory.

Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
Reviewed-by: Claudiu Manoil <claudiu.manoil@xxxxxxx>
---
 drivers/net/ethernet/freescale/enetc/enetc.c | 121 ++++++++++---------
 1 file changed, 62 insertions(+), 59 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 032d8eadd003..b84c88a76762 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -2965,13 +2965,70 @@ int enetc_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd)
 }
 EXPORT_SYMBOL_GPL(enetc_ioctl);
 
+static int enetc_bdr_init(struct enetc_ndev_priv *priv, int i, int v_tx_rings)
+{
+	struct enetc_int_vector *v __free(kfree);
+	struct enetc_bdr *bdr;
+	int j, err;
+
+	v = kzalloc(struct_size(v, tx_ring, v_tx_rings), GFP_KERNEL);
+	if (!v)
+		return -ENOMEM;
+
+	bdr = &v->rx_ring;
+	bdr->index = i;
+	bdr->ndev = priv->ndev;
+	bdr->dev = priv->dev;
+	bdr->bd_count = priv->rx_bd_count;
+	bdr->buffer_offset = ENETC_RXB_PAD;
+	priv->rx_ring[i] = bdr;
+
+	err = xdp_rxq_info_reg(&bdr->xdp.rxq, priv->ndev, i, 0);
+	if (err)
+		return err;
+
+	err = xdp_rxq_info_reg_mem_model(&bdr->xdp.rxq,
+					 MEM_TYPE_PAGE_SHARED, NULL);
+	if (err) {
+		xdp_rxq_info_unreg(&bdr->xdp.rxq);
+		return err;
+	}
+
+	/* init defaults for adaptive IC */
+	if (priv->ic_mode & ENETC_IC_RX_ADAPTIVE) {
+		v->rx_ictt = 0x1;
+		v->rx_dim_en = true;
+	}
+	INIT_WORK(&v->rx_dim.work, enetc_rx_dim_work);
+	netif_napi_add(priv->ndev, &v->napi, enetc_poll);
+	v->count_tx_rings = v_tx_rings;
+
+	for (j = 0; j < v_tx_rings; j++) {
+		int idx;
+
+		/* default tx ring mapping policy */
+		idx = priv->bdr_int_num * j + i;
+		__set_bit(idx, &v->tx_rings_map);
+		bdr = &v->tx_ring[j];
+		bdr->index = idx;
+		bdr->ndev = priv->ndev;
+		bdr->dev = priv->dev;
+		bdr->bd_count = priv->tx_bd_count;
+		priv->tx_ring[idx] = bdr;
+	}
+
+	priv->int_vector[i] = no_free_ptr(v);
+
+	return 0;
+}
+
 int enetc_alloc_msix(struct enetc_ndev_priv *priv)
 {
 	struct pci_dev *pdev = priv->si->pdev;
+	int v_tx_rings, v_remainder;
 	int num_stack_tx_queues;
 	int first_xdp_tx_ring;
 	int i, n, err, nvec;
-	int v_tx_rings;
 
 	nvec = ENETC_BDR_INT_BASE_IDX + priv->bdr_int_num;
 	/* allocate MSIX for both messaging and Rx/Tx interrupts */
@@ -2985,65 +3042,11 @@ int enetc_alloc_msix(struct enetc_ndev_priv *priv)
 
 	/* # of tx rings per int vector */
 	v_tx_rings = priv->num_tx_rings / priv->bdr_int_num;
+	v_remainder = priv->num_tx_rings % priv->bdr_int_num;
 
-	for (i = 0; i < priv->bdr_int_num; i++) {
-		struct enetc_int_vector *v;
-		struct enetc_bdr *bdr;
-		int j;
-
-		v = kzalloc(struct_size(v, tx_ring, v_tx_rings), GFP_KERNEL);
-		if (!v) {
-			err = -ENOMEM;
-			goto fail;
-		}
-
-		priv->int_vector[i] = v;
-
-		bdr = &v->rx_ring;
-		bdr->index = i;
-		bdr->ndev = priv->ndev;
-		bdr->dev = priv->dev;
-		bdr->bd_count = priv->rx_bd_count;
-		bdr->buffer_offset = ENETC_RXB_PAD;
-		priv->rx_ring[i] = bdr;
-
-		err = xdp_rxq_info_reg(&bdr->xdp.rxq, priv->ndev, i, 0);
-		if (err) {
-			kfree(v);
-			goto fail;
-		}
-
-		err = xdp_rxq_info_reg_mem_model(&bdr->xdp.rxq,
-						 MEM_TYPE_PAGE_SHARED, NULL);
-		if (err) {
-			xdp_rxq_info_unreg(&bdr->xdp.rxq);
-			kfree(v);
-			goto fail;
-		}
-
-		/* init defaults for adaptive IC */
-		if (priv->ic_mode & ENETC_IC_RX_ADAPTIVE) {
-			v->rx_ictt = 0x1;
-			v->rx_dim_en = true;
-		}
-		INIT_WORK(&v->rx_dim.work, enetc_rx_dim_work);
-		netif_napi_add(priv->ndev, &v->napi, enetc_poll);
-		v->count_tx_rings = v_tx_rings;
-
-		for (j = 0; j < v_tx_rings; j++) {
-			int idx;
-
-			/* default tx ring mapping policy */
-			idx = priv->bdr_int_num * j + i;
-			__set_bit(idx, &v->tx_rings_map);
-			bdr = &v->tx_ring[j];
-			bdr->index = idx;
-			bdr->ndev = priv->ndev;
-			bdr->dev = priv->dev;
-			bdr->bd_count = priv->tx_bd_count;
-			priv->tx_ring[idx] = bdr;
-		}
-	}
+	for (i = 0; i < priv->bdr_int_num; i++)
+		enetc_bdr_init(priv, i,
+			       i < v_remainder ? v_tx_rings + 1 : v_tx_rings);
 
 	num_stack_tx_queues = enetc_num_stack_tx_queues(priv);
 
-- 
2.34.1