Re: [PATCH v6 5/7] can: kvaser_usb: Update interface state before exiting on OOM
From: Andri Yngvason
Date: Mon Jan 26 2015 - 05:31:35 EST
Quoting Ahmed S. Darwish (2015-01-26 05:27:19)
> From: Ahmed S. Darwish <ahmed.darwish@xxxxxxxxx>
>
> Update all of the can interface's state and error counters before
> trying any skb allocation that can actually fail with -ENOMEM.
>
> Suggested-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
> Signed-off-by: Ahmed S. Darwish <ahmed.darwish@xxxxxxxxx>
> ---
> drivers/net/can/usb/kvaser_usb.c | 181 ++++++++++++++++++++++----------------
> 1 files changed, 105 insertions(+), 76 deletions(-)
>
> diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
> index 7af379c..f57ce55 100644
> --- a/drivers/net/can/usb/kvaser_usb.c
> +++ b/drivers/net/can/usb/kvaser_usb.c
> @@ -273,6 +273,10 @@ struct kvaser_msg {
> } u;
> } __packed;
>
> +struct kvaser_usb_error_summary {
> + u8 channel, status, txerr, rxerr, error_factor;
> +};
> +
> struct kvaser_usb_tx_urb_context {
> struct kvaser_usb_net_priv *priv;
> u32 echo_index;
> @@ -615,6 +619,54 @@ static void kvaser_usb_unlink_tx_urbs(struct kvaser_usb_net_priv *priv)
> priv->tx_contexts[i].echo_index = MAX_TX_URBS;
> }
>
> +static void kvaser_usb_rx_error_update_can_state(struct kvaser_usb_net_priv *priv,
> + const struct kvaser_usb_error_summary *es)
> +{
> + struct net_device_stats *stats;
> + enum can_state new_state;
> +
> + stats = &priv->netdev->stats;
> + new_state = priv->can.state;
> +
> + netdev_dbg(priv->netdev, "Error status: 0x%02x\n", es->status);
> +
> + if (es->status & (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET)) {
> + priv->can.can_stats.bus_off++;
> + new_state = CAN_STATE_BUS_OFF;
> + } else if (es->status & M16C_STATE_BUS_PASSIVE) {
> + if (priv->can.state != CAN_STATE_ERROR_PASSIVE)
> + priv->can.can_stats.error_passive++;
> + new_state = CAN_STATE_ERROR_PASSIVE;
> + } else if (es->status & M16C_STATE_BUS_ERROR) {
> + if ((priv->can.state < CAN_STATE_ERROR_WARNING) &&
> + ((es->txerr >= 96) || (es->rxerr >= 96))) {
> + priv->can.can_stats.error_warning++;
> + new_state = CAN_STATE_ERROR_WARNING;
> + } else if ((priv->can.state > CAN_STATE_ERROR_ACTIVE) &&
> + ((es->txerr < 96) && (es->rxerr < 96))) {
> + new_state = CAN_STATE_ERROR_ACTIVE;
> + }
> + }
> +
> + if (!es->status)
> + new_state = CAN_STATE_ERROR_ACTIVE;
> +
> + if (priv->can.restart_ms &&
> + (priv->can.state >= CAN_STATE_BUS_OFF) &&
> + (new_state < CAN_STATE_BUS_OFF)) {
> + priv->can.can_stats.restarts++;
> + }
> +
> + if (es->error_factor) {
> + priv->can.can_stats.bus_error++;
> + stats->rx_errors++;
> + }
> +
> + priv->bec.txerr = es->txerr;
> + priv->bec.rxerr = es->rxerr;
> + priv->can.state = new_state;
> +}
> +
> static void kvaser_usb_rx_error(const struct kvaser_usb *dev,
> const struct kvaser_msg *msg)
> {
> @@ -622,30 +674,30 @@ static void kvaser_usb_rx_error(const struct kvaser_usb *dev,
> struct sk_buff *skb;
> struct net_device_stats *stats;
> struct kvaser_usb_net_priv *priv;
> - unsigned int new_state;
> - u8 channel, status, txerr, rxerr, error_factor;
> + struct kvaser_usb_error_summary es = { };
> + enum can_state old_state;
>
> switch (msg->id) {
> case CMD_CAN_ERROR_EVENT:
> - channel = msg->u.error_event.channel;
> - status = msg->u.error_event.status;
> - txerr = msg->u.error_event.tx_errors_count;
> - rxerr = msg->u.error_event.rx_errors_count;
> - error_factor = msg->u.error_event.error_factor;
> + es.channel = msg->u.error_event.channel;
> + es.status = msg->u.error_event.status;
> + es.txerr = msg->u.error_event.tx_errors_count;
> + es.rxerr = msg->u.error_event.rx_errors_count;
> + es.error_factor = msg->u.error_event.error_factor;
> break;
> case CMD_LOG_MESSAGE:
> - channel = msg->u.log_message.channel;
> - status = msg->u.log_message.data[0];
> - txerr = msg->u.log_message.data[2];
> - rxerr = msg->u.log_message.data[3];
> - error_factor = msg->u.log_message.data[1];
> + es.channel = msg->u.log_message.channel;
> + es.status = msg->u.log_message.data[0];
> + es.txerr = msg->u.log_message.data[2];
> + es.rxerr = msg->u.log_message.data[3];
> + es.error_factor = msg->u.log_message.data[1];
> break;
> case CMD_CHIP_STATE_EVENT:
> - channel = msg->u.chip_state_event.channel;
> - status = msg->u.chip_state_event.status;
> - txerr = msg->u.chip_state_event.tx_errors_count;
> - rxerr = msg->u.chip_state_event.rx_errors_count;
> - error_factor = 0;
> + es.channel = msg->u.chip_state_event.channel;
> + es.status = msg->u.chip_state_event.status;
> + es.txerr = msg->u.chip_state_event.tx_errors_count;
> + es.rxerr = msg->u.chip_state_event.rx_errors_count;
> + es.error_factor = 0;
> break;
> default:
> dev_err(dev->udev->dev.parent, "Invalid msg id (%d)\n",
> @@ -653,116 +705,93 @@ static void kvaser_usb_rx_error(const struct kvaser_usb *dev,
> return;
> }
>
> - if (channel >= dev->nchannels) {
> + if (es.channel >= dev->nchannels) {
> dev_err(dev->udev->dev.parent,
> - "Invalid channel number (%d)\n", channel);
> + "Invalid channel number (%d)\n", es.channel);
> return;
> }
>
> - priv = dev->nets[channel];
> + priv = dev->nets[es.channel];
> stats = &priv->netdev->stats;
>
> + /* Update all of the can interface's state and error counters before
> + * trying any skb allocation that can actually fail with -ENOMEM.
> + */
> + old_state = priv->can.state;
> + kvaser_usb_rx_error_update_can_state(priv, &es);
> +
> skb = alloc_can_err_skb(priv->netdev, &cf);
> if (!skb) {
> stats->rx_dropped++;
> return;
> }
>
> - new_state = priv->can.state;
> -
> - netdev_dbg(priv->netdev, "Error status: 0x%02x\n", status);
> -
> - if (status & (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET)) {
> + if (es.status & (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET)) {
> cf->can_id |= CAN_ERR_BUSOFF;
>
> - priv->can.can_stats.bus_off++;
> if (!priv->can.restart_ms)
> kvaser_usb_simple_msg_async(priv, CMD_STOP_CHIP);
> -
> netif_carrier_off(priv->netdev);
> -
> - new_state = CAN_STATE_BUS_OFF;
> - } else if (status & M16C_STATE_BUS_PASSIVE) {
> - if (priv->can.state != CAN_STATE_ERROR_PASSIVE) {
> + } else if (es.status & M16C_STATE_BUS_PASSIVE) {
> + if (old_state != CAN_STATE_ERROR_PASSIVE) {
> cf->can_id |= CAN_ERR_CRTL;
>
> - if (txerr || rxerr)
> - cf->data[1] = (txerr > rxerr)
> + if (es.txerr || es.rxerr)
> + cf->data[1] = (es.txerr > es.rxerr)
> ? CAN_ERR_CRTL_TX_PASSIVE
> : CAN_ERR_CRTL_RX_PASSIVE;
> else
> cf->data[1] = CAN_ERR_CRTL_TX_PASSIVE |
> CAN_ERR_CRTL_RX_PASSIVE;
> -
> - priv->can.can_stats.error_passive++;
> }
> -
> - new_state = CAN_STATE_ERROR_PASSIVE;
> - } else if (status & M16C_STATE_BUS_ERROR) {
> - if ((priv->can.state < CAN_STATE_ERROR_WARNING) &&
> - ((txerr >= 96) || (rxerr >= 96))) {
> + } else if (es.status & M16C_STATE_BUS_ERROR) {
> + if ((old_state < CAN_STATE_ERROR_WARNING) &&
> + ((es.txerr >= 96) || (es.rxerr >= 96))) {
> cf->can_id |= CAN_ERR_CRTL;
> - cf->data[1] = (txerr > rxerr)
> + cf->data[1] = (es.txerr > es.rxerr)
> ? CAN_ERR_CRTL_TX_WARNING
> : CAN_ERR_CRTL_RX_WARNING;
> -
> - priv->can.can_stats.error_warning++;
> - new_state = CAN_STATE_ERROR_WARNING;
> - } else if ((priv->can.state > CAN_STATE_ERROR_ACTIVE) &&
> - ((txerr < 96) && (rxerr < 96))) {
> + } else if ((old_state > CAN_STATE_ERROR_ACTIVE) &&
> + ((es.txerr < 96) && (es.rxerr < 96))) {
> cf->can_id |= CAN_ERR_PROT;
> cf->data[2] = CAN_ERR_PROT_ACTIVE;
> -
> - new_state = CAN_STATE_ERROR_ACTIVE;
> }
> }
>
> - if (!status) {
> + if (!es.status) {
> cf->can_id |= CAN_ERR_PROT;
> cf->data[2] = CAN_ERR_PROT_ACTIVE;
> -
> - new_state = CAN_STATE_ERROR_ACTIVE;
> }
>
> if (priv->can.restart_ms &&
> - (priv->can.state >= CAN_STATE_BUS_OFF) &&
> - (new_state < CAN_STATE_BUS_OFF)) {
> + (old_state >= CAN_STATE_BUS_OFF) &&
> + (priv->can.state < CAN_STATE_BUS_OFF)) {
> cf->can_id |= CAN_ERR_RESTARTED;
> netif_carrier_on(priv->netdev);
> -
> - priv->can.can_stats.restarts++;
> }
>
> - if (error_factor) {
> - priv->can.can_stats.bus_error++;
> - stats->rx_errors++;
> -
> + if (es.error_factor) {
> cf->can_id |= CAN_ERR_BUSERROR | CAN_ERR_PROT;
>
> - if (error_factor & M16C_EF_ACKE)
> + if (es.error_factor & M16C_EF_ACKE)
> cf->data[3] |= (CAN_ERR_PROT_LOC_ACK);
> - if (error_factor & M16C_EF_CRCE)
> + if (es.error_factor & M16C_EF_CRCE)
> cf->data[3] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
> CAN_ERR_PROT_LOC_CRC_DEL);
> - if (error_factor & M16C_EF_FORME)
> + if (es.error_factor & M16C_EF_FORME)
> cf->data[2] |= CAN_ERR_PROT_FORM;
> - if (error_factor & M16C_EF_STFE)
> + if (es.error_factor & M16C_EF_STFE)
> cf->data[2] |= CAN_ERR_PROT_STUFF;
> - if (error_factor & M16C_EF_BITE0)
> + if (es.error_factor & M16C_EF_BITE0)
> cf->data[2] |= CAN_ERR_PROT_BIT0;
> - if (error_factor & M16C_EF_BITE1)
> + if (es.error_factor & M16C_EF_BITE1)
> cf->data[2] |= CAN_ERR_PROT_BIT1;
> - if (error_factor & M16C_EF_TRE)
> + if (es.error_factor & M16C_EF_TRE)
> cf->data[2] |= CAN_ERR_PROT_TX;
> }
>
> - cf->data[6] = txerr;
> - cf->data[7] = rxerr;
> -
> - priv->bec.txerr = txerr;
> - priv->bec.rxerr = rxerr;
> -
> - priv->can.state = new_state;
> + cf->data[6] = es.txerr;
> + cf->data[7] = es.rxerr;
>
> stats->rx_packets++;
> stats->rx_bytes += cf->can_dlc;
> @@ -786,6 +815,9 @@ static void kvaser_usb_rx_can_err(const struct kvaser_usb_net_priv *priv,
> }
>
> if (msg->u.rx_can.flag & MSG_FLAG_OVERRUN) {
> + stats->rx_over_errors++;
> + stats->rx_errors++;
> +
> skb = alloc_can_err_skb(priv->netdev, &cf);
> if (!skb) {
> stats->rx_dropped++;
> @@ -795,9 +827,6 @@ static void kvaser_usb_rx_can_err(const struct kvaser_usb_net_priv *priv,
> cf->can_id |= CAN_ERR_CRTL;
> cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
>
> - stats->rx_over_errors++;
> - stats->rx_errors++;
> -
> stats->rx_packets++;
> stats->rx_bytes += cf->can_dlc;
> netif_rx(skb);
> --
> 1.7.7.6
Looks good to me.
--
Andri
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/