Messages in this thread Patch in this message | | | Date | Sun, 25 Jan 2015 05:21:47 +0200 | From | "Ahmed S. Darwish" <> | Subject | Re: [PATCH v5 2/5] can: kvaser_usb: Consolidate and unify state change handling |
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Hi!
On Wed, Jan 21, 2015 at 04:20:25PM +0000, Andri Yngvason wrote: > Quoting Ahmed S. Darwish (2015-01-20 21:45:37) > > From: Ahmed S. Darwish <ahmed.darwish@valeo.com> > > > > Replace most of the can interface's state and error counters > > handling with the new can-dev can_change_state() mechanism. > > > > Suggested-by: Andri Yngvason <andri.yngvason@marel.com> > > Signed-off-by: Ahmed S. Darwish <ahmed.darwish@valeo.com> > > --- > > drivers/net/can/usb/kvaser_usb.c | 114 +++++++++++++++++++-------------------- > > 1 file changed, 55 insertions(+), 59 deletions(-) > > > > diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c > > index 971c5f9..0386d3f 100644 > > --- a/drivers/net/can/usb/kvaser_usb.c > > +++ b/drivers/net/can/usb/kvaser_usb.c > > @@ -620,40 +620,43 @@ static void kvaser_usb_unlink_tx_urbs(struct kvaser_usb_net_priv *priv) > > } > > > > static void kvaser_usb_rx_error_update_can_state(struct kvaser_usb_net_priv *priv, > > - const struct kvaser_usb_error_summary *es) > > + const struct kvaser_usb_error_summary *es, > > + struct can_frame *cf) > > { > > struct net_device_stats *stats; > > - enum can_state new_state; > > - > > - stats = &priv->netdev->stats; > > - new_state = priv->can.state; > > + enum can_state cur_state, new_state, tx_state, rx_state; > > > > netdev_dbg(priv->netdev, "Error status: 0x%02x\n", es->status); > > > > - if (es->status & M16C_STATE_BUS_OFF) { > > - priv->can.can_stats.bus_off++; > > + stats = &priv->netdev->stats; > > + new_state = cur_state = priv->can.state; > > + > > + if (es->status & M16C_STATE_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++; > > + else if (es->status & M16C_STATE_BUS_PASSIVE) > > new_state = CAN_STATE_ERROR_PASSIVE; > > - } > > > > 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++; > > + if ((cur_state < CAN_STATE_ERROR_WARNING) && > > + ((es->txerr >= 96) || (es->rxerr >= 96))) > > new_state = CAN_STATE_ERROR_WARNING; > > - } else if (priv->can.state > CAN_STATE_ERROR_ACTIVE) { > > + else if (cur_state > CAN_STATE_ERROR_ACTIVE) > > new_state = CAN_STATE_ERROR_ACTIVE; > > - } > > } > > > > if (!es->status) > > new_state = CAN_STATE_ERROR_ACTIVE; > > > > + if (new_state != cur_state) { > > + tx_state = (es->txerr >= es->rxerr) ? new_state : 0; > > + rx_state = (es->txerr <= es->rxerr) ? new_state : 0; > > + > > + can_change_state(priv->netdev, cf, tx_state, rx_state); > > This (below) is redundant. It doesn't harm but at this point can_change_state > has set priv->can.state to new_state. > > > + new_state = priv->can.state; > > + } > > +
Correct; I will remove it.
> > if (priv->can.restart_ms && > > - (priv->can.state >= CAN_STATE_BUS_OFF) && > > + (cur_state >= CAN_STATE_BUS_OFF) && > > (new_state < CAN_STATE_BUS_OFF)) { > > priv->can.can_stats.restarts++; > > } > > @@ -665,18 +668,17 @@ static void kvaser_usb_rx_error_update_can_state(struct kvaser_usb_net_priv *pri > > > > 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) > > { > > - struct can_frame *cf; > > + struct can_frame *cf, tmp_cf = { .can_id = CAN_ERR_FLAG, .can_dlc = CAN_ERR_DLC }; > > struct sk_buff *skb; > > struct net_device_stats *stats; > > struct kvaser_usb_net_priv *priv; > > struct kvaser_usb_error_summary es = { }; > > - enum can_state old_state; > > + enum can_state old_state, new_state; > > > > switch (msg->id) { > > case CMD_CAN_ERROR_EVENT: > > @@ -721,60 +723,54 @@ static void kvaser_usb_rx_error(const struct kvaser_usb *dev, > > } > > > > /* Update all of the can interface's state and error counters before > > - * trying any skb allocation that can actually fail with -ENOMEM. > > + * trying any memory allocation that can actually fail with -ENOMEM. > > + * > > + * We send a temporary stack-allocated error can frame to > > + * can_change_state() for the very same reason. > > + * > > + * TODO: Split can_change_state() responsibility between updating the > > + * can interface's state and counters, and the setting up of can error > > + * frame ID and data to userspace. Remove stack allocation afterwards. > > */ > > old_state = priv->can.state; > > - kvaser_usb_rx_error_update_can_state(priv, &es); > > + kvaser_usb_rx_error_update_can_state(priv, &es, &tmp_cf); > > + new_state = priv->can.state; > > > > skb = alloc_can_err_skb(priv->netdev, &cf); > > if (!skb) { > > stats->rx_dropped++; > > return; > > } > > + memcpy(cf, &tmp_cf, sizeof(*cf)); > > > > - if (es.status & M16C_STATE_BUS_OFF) { > > - cf->can_id |= CAN_ERR_BUSOFF; > > - > > - if (!priv->can.restart_ms) > > - kvaser_usb_simple_msg_async(priv, CMD_STOP_CHIP); > > - netif_carrier_off(priv->netdev); > > - } else if (es.status & M16C_STATE_BUS_PASSIVE) { > > - if (old_state != CAN_STATE_ERROR_PASSIVE) { > > - cf->can_id |= CAN_ERR_CRTL; > > - > > - 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; > > + if (new_state != old_state) { > > + if (es.status & M16C_STATE_BUS_OFF) { > > + if (!priv->can.restart_ms) > > + kvaser_usb_simple_msg_async(priv, CMD_STOP_CHIP); > > + netif_carrier_off(priv->netdev); > > + } > > + > > This block [below] is wrong. The usage of PROT_ACTIVE is based on a misunderstanding. > It's used in some drivers to signify back-to-error-active but its original > meaning is something completely different, AFAIK. > This is handled in can_change_state() using a new CTRL message; namely: > CAN_ERR_CTRL_ACTIVE. The newest version of can-utils is up to date with this. > > > + if (es.status == M16C_STATE_BUS_ERROR) { > > + if ((old_state >= CAN_STATE_ERROR_WARNING) || > > + (es.txerr < 96 && es.rxerr < 96)) { > > + if (old_state > CAN_STATE_ERROR_ACTIVE) { > > + cf->can_id |= CAN_ERR_PROT; > > + cf->data[2] = CAN_ERR_PROT_ACTIVE; > > + } > > + } > > }
So I would just make the new_state equals CAN_STATE_ERROR_ACTIVE, and then can_change_state() will do the right thing? Excellent!! This means the entire block above can be removed ;-)
[ On another note, the block's if conditions above are faulty and fixed in patch #3. This patch (#2) used can_change_state() without changing any of that faulty logic to ease any future bisection. ]
> > - } > > > > - 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] = (es.txerr > es.rxerr) > > - ? CAN_ERR_CRTL_TX_WARNING > > - : CAN_ERR_CRTL_RX_WARNING; > > - } else if (old_state > CAN_STATE_ERROR_ACTIVE) { > > This is also redundant, and wrong: > > > + if (!es.status) { > > cf->can_id |= CAN_ERR_PROT; > > cf->data[2] = CAN_ERR_PROT_ACTIVE; > > } > > - }
As in the above; extra code to be removed, yay! ;-)
> > > > - if (!es.status) { > > - cf->can_id |= CAN_ERR_PROT; > > - cf->data[2] = CAN_ERR_PROT_ACTIVE; > > - } > > - > > - if (priv->can.restart_ms && > > - (old_state >= CAN_STATE_BUS_OFF) && > > - (priv->can.state < CAN_STATE_BUS_OFF)) { > > - cf->can_id |= CAN_ERR_RESTARTED; > > - netif_carrier_on(priv->netdev); > > + if (priv->can.restart_ms && > > + (old_state >= CAN_STATE_BUS_OFF) && > > + (new_state < CAN_STATE_BUS_OFF)) { > > + cf->can_id |= CAN_ERR_RESTARTED; > > + netif_carrier_on(priv->netdev); > > + } > > } > > > > if (es.error_factor) { > > -- > > 1.9.1 > > Looking over the patch again, I've noticed that there > are a few things that are not quite right. >
The state-handlig code has become much simpler since your reveiw and Kleine-Budde's one. Thanks a lot for all the effort.
Regards, Darwish
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