Re: [PATCH can-next v5 1/2] can: add tx/rx LED trigger support

From: Marc Kleine-Budde
Date: Wed Aug 01 2012 - 08:18:44 EST


On 08/01/2012 02:06 PM, Oliver Hartkopp wrote:
> Sorry for this potentially mangled mail from my webmail access ...
>
> Fabio Baltieri <fabio.baltieri@xxxxxxxxx> hat am 1. August 2012 um 13:49
> geschrieben:
>
>> +void devm_can_led_init(struct net_device *netdev)
>> +{
>> + struct can_priv *priv = netdev_priv(netdev);
>> + void *res;
>> +
>> + res = devres_alloc(can_led_release, 0, GFP_KERNEL);
>> + if (!res)
>> + goto err_out;
>> +
>> + priv->tx_led_trig_name = kasprintf(GFP_KERNEL, "%s-tx", netdev->name);
>
> IMO putting a string with 8 or 9 bytes into a separate kmalloc memory sniplet is
> pretty oversized.
> Ok - these functions provide to hide the complexitiy for allocating and storing
> strings, which is
> definitely fine for path names and these kind of strings that are not known in
> length and probably
> more than 100 bytes long.
>
> But in this case i would suggest to allocate a fixed space in can_priv, as we
> know the string length
> very good (IFNAMSZ + strlen("-tx")) and there's no reason to get all the
> overhead from three kmallocs
> instead of one for that small memory allocations.
>
> So i would suggest:
>
>> @@ -52,6 +53,13 @@ struct can_priv {
>>
>> unsigned int echo_skb_max;
>> struct sk_buff **echo_skb;
>> +
>> +#ifdef CONFIG_CAN_LEDS
>> + struct led_trigger *tx_led_trig;
>> + char *tx_led_trig_name;
>
> char tx_led_trig_name[IFNAMSZ+4];
>
>> + struct led_trigger *rx_led_trig;
>> + char *rx_led_trig_name;
>
> char rx_led_trig_name[IFNAMSZ+4];
>
>> +#endif
>> };

Sounds reasonable. Please Introduce a #define for "IFNAMSZ + 4" and
document where the 4 comes from. Send a v6 patch, I'll force update the
git repo, after you have Oliver's Acked-by.

Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |

Attachment: signature.asc
Description: OpenPGP digital signature