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Subject[PATCH 5.3 038/105] ravb: implement MTU change while device is up
Date
From: Ulrich Hecht <uli+renesas@fpond.eu>

[ Upstream commit 15fb35fa9ff456b81159033eba6397fcee85e671 ]

Pre-allocates buffers sufficient for the maximum supported MTU (2026) in
order to eliminate the possibility of resource exhaustion when changing the
MTU while the device is up.

Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/renesas/ravb.h | 3 ++-
drivers/net/ethernet/renesas/ravb_main.c | 26 +++++++++++++-----------
2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index ac9195add8116..7090229398227 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -960,6 +960,8 @@ enum RAVB_QUEUE {
#define NUM_RX_QUEUE 2
#define NUM_TX_QUEUE 2

+#define RX_BUF_SZ (2048 - ETH_FCS_LEN + sizeof(__sum16))
+
/* TX descriptors per packet */
#define NUM_TX_DESC_GEN2 2
#define NUM_TX_DESC_GEN3 1
@@ -1023,7 +1025,6 @@ struct ravb_private {
u32 dirty_rx[NUM_RX_QUEUE]; /* Producer ring indices */
u32 cur_tx[NUM_TX_QUEUE];
u32 dirty_tx[NUM_TX_QUEUE];
- u32 rx_buf_sz; /* Based on MTU+slack. */
struct napi_struct napi[NUM_RX_QUEUE];
struct work_struct work;
/* MII transceiver section. */
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 6cacd5e893aca..393644833cd57 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -230,7 +230,7 @@ static void ravb_ring_free(struct net_device *ndev, int q)
le32_to_cpu(desc->dptr)))
dma_unmap_single(ndev->dev.parent,
le32_to_cpu(desc->dptr),
- priv->rx_buf_sz,
+ RX_BUF_SZ,
DMA_FROM_DEVICE);
}
ring_size = sizeof(struct ravb_ex_rx_desc) *
@@ -293,9 +293,9 @@ static void ravb_ring_format(struct net_device *ndev, int q)
for (i = 0; i < priv->num_rx_ring[q]; i++) {
/* RX descriptor */
rx_desc = &priv->rx_ring[q][i];
- rx_desc->ds_cc = cpu_to_le16(priv->rx_buf_sz);
+ rx_desc->ds_cc = cpu_to_le16(RX_BUF_SZ);
dma_addr = dma_map_single(ndev->dev.parent, priv->rx_skb[q][i]->data,
- priv->rx_buf_sz,
+ RX_BUF_SZ,
DMA_FROM_DEVICE);
/* We just set the data size to 0 for a failed mapping which
* should prevent DMA from happening...
@@ -342,9 +342,6 @@ static int ravb_ring_init(struct net_device *ndev, int q)
int ring_size;
int i;

- priv->rx_buf_sz = (ndev->mtu <= 1492 ? PKT_BUF_SZ : ndev->mtu) +
- ETH_HLEN + VLAN_HLEN + sizeof(__sum16);
-
/* Allocate RX and TX skb rings */
priv->rx_skb[q] = kcalloc(priv->num_rx_ring[q],
sizeof(*priv->rx_skb[q]), GFP_KERNEL);
@@ -354,7 +351,7 @@ static int ravb_ring_init(struct net_device *ndev, int q)
goto error;

for (i = 0; i < priv->num_rx_ring[q]; i++) {
- skb = netdev_alloc_skb(ndev, priv->rx_buf_sz + RAVB_ALIGN - 1);
+ skb = netdev_alloc_skb(ndev, RX_BUF_SZ + RAVB_ALIGN - 1);
if (!skb)
goto error;
ravb_set_buffer_align(skb);
@@ -590,7 +587,7 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q)
skb = priv->rx_skb[q][entry];
priv->rx_skb[q][entry] = NULL;
dma_unmap_single(ndev->dev.parent, le32_to_cpu(desc->dptr),
- priv->rx_buf_sz,
+ RX_BUF_SZ,
DMA_FROM_DEVICE);
get_ts &= (q == RAVB_NC) ?
RAVB_RXTSTAMP_TYPE_V2_L2_EVENT :
@@ -623,11 +620,11 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q)
for (; priv->cur_rx[q] - priv->dirty_rx[q] > 0; priv->dirty_rx[q]++) {
entry = priv->dirty_rx[q] % priv->num_rx_ring[q];
desc = &priv->rx_ring[q][entry];
- desc->ds_cc = cpu_to_le16(priv->rx_buf_sz);
+ desc->ds_cc = cpu_to_le16(RX_BUF_SZ);

if (!priv->rx_skb[q][entry]) {
skb = netdev_alloc_skb(ndev,
- priv->rx_buf_sz +
+ RX_BUF_SZ +
RAVB_ALIGN - 1);
if (!skb)
break; /* Better luck next round. */
@@ -1814,10 +1811,15 @@ static int ravb_do_ioctl(struct net_device *ndev, struct ifreq *req, int cmd)

static int ravb_change_mtu(struct net_device *ndev, int new_mtu)
{
- if (netif_running(ndev))
- return -EBUSY;
+ struct ravb_private *priv = netdev_priv(ndev);

ndev->mtu = new_mtu;
+
+ if (netif_running(ndev)) {
+ synchronize_irq(priv->emac_irq);
+ ravb_emac_init(ndev);
+ }
+
netdev_update_features(ndev);

return 0;
--
2.20.1


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