[LEDE-DEV] [PATCH 1/3] ag71xx: Remove timestamp struct member and use trans_start instead

[Felix Fietkau]

On 2018-02-06 23:27, Rosen Penev wrote:
> Small speedup for TX.
> 
> Based on a Qualcomm commit. ag->timestamp = jiffies was not replaced with netif_trans_update(dev) because of this quote:
> 
> It should be noted that after this series several instances
> of netif_trans_update() are useless (if they occur in
> .ndo_start_xmit and driver doesn't set LLTX flag -- stack already
> did an update).
> 
> From: http://lists.openwall.net/netdev/2016/05/03/87
> 
> Signed-off-by: Rosen Penev <rosenp at gmail.com>
> ---
> @@ -930,7 +929,7 @@ static bool ag71xx_check_dma_stuck(struct ag71xx *ag)
>  {
>  	u32 rx_sm, tx_sm, rx_fd;
>  
> -	if (likely(time_before(jiffies, ag->timestamp + HZ/10)))
> +	if (likely(time_before(jiffies, dev_trans_start(ag->dev) + HZ/10)))
dev_trans_start() does some extra checks that are unnecessary. You
should use netdev_get_tx_queue(dev, 0)->trans_start instead.

- Felix