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Subject[PATCH V2 2/2] can: xilinx_can: Fix usage of skb memory
Date
As per linux can framework, driver not allowed to touch the skb memory
after can_put_echo_skb() call.
This patch fixes the same.
https://www.spinics.net/lists/linux-can/msg02199.html

Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
Reviewed-by: Appana Durga Kedareswara Rao <appana.durga.rao@xilinx.com>
---
drivers/net/can/xilinx_can.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index c5f05b994435..464af939cd8a 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -542,16 +542,17 @@ static int xcan_do_set_mode(struct net_device *ndev, enum can_mode mode)

/**
* xcan_write_frame - Write a frame to HW
- * @priv: Driver private data structure
+ * @ndev: Pointer to net_device structure
* @skb: sk_buff pointer that contains data to be Txed
* @frame_offset: Register offset to write the frame to
*/
-static void xcan_write_frame(struct xcan_priv *priv, struct sk_buff *skb,
+static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb,
int frame_offset)
{
u32 id, dlc, data[2] = {0, 0};
struct canfd_frame *cf = (struct canfd_frame *)skb->data;
u32 ramoff, dwindex = 0, i;
+ struct xcan_priv *priv = netdev_priv(ndev);

/* Watch carefully on the bit sequence */
if (cf->can_id & CAN_EFF_FLAG) {
@@ -587,6 +588,14 @@ static void xcan_write_frame(struct xcan_priv *priv, struct sk_buff *skb,
dlc |= XCAN_DLCR_EDL_MASK;
}

+ if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) &&
+ (priv->devtype.flags & XCAN_FLAG_TXFEMP))
+ can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max);
+ else
+ can_put_echo_skb(skb, ndev, 0);
+
+ priv->tx_head++;
+
priv->write_reg(priv, XCAN_FRAME_ID_OFFSET(frame_offset), id);
/* If the CAN frame is RTR frame this write triggers transmission
* (not on CAN FD)
@@ -638,13 +647,9 @@ static int xcan_start_xmit_fifo(struct sk_buff *skb, struct net_device *ndev)
XCAN_SR_TXFLL_MASK))
return -ENOSPC;

- can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max);
-
spin_lock_irqsave(&priv->tx_lock, flags);

- priv->tx_head++;
-
- xcan_write_frame(priv, skb, XCAN_TXFIFO_OFFSET);
+ xcan_write_frame(ndev, skb, XCAN_TXFIFO_OFFSET);

/* Clear TX-FIFO-empty interrupt for xcan_tx_interrupt() */
if (priv->tx_max > 1)
@@ -675,13 +680,9 @@ static int xcan_start_xmit_mailbox(struct sk_buff *skb, struct net_device *ndev)
BIT(XCAN_TX_MAILBOX_IDX)))
return -ENOSPC;

- can_put_echo_skb(skb, ndev, 0);
-
spin_lock_irqsave(&priv->tx_lock, flags);

- priv->tx_head++;
-
- xcan_write_frame(priv, skb,
+ xcan_write_frame(ndev, skb,
XCAN_TXMSG_FRAME_OFFSET(XCAN_TX_MAILBOX_IDX));

/* Mark buffer as ready for transmit */
--
2.7.4
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