Re: [PATCH 13/15] net: jme: Convert tasklet API to new bottom half workqueue mechanism

[Paolo Abeni]

On Thu, 2024-06-20 at 22:05 -0700, Allen Pais wrote:
> Migrate tasklet APIs to the new bottom half workqueue mechanism. It
> replaces all occurrences of tasklet usage with the appropriate workqueue
> APIs throughout the jme driver. This transition ensures compatibility
> with the latest design and enhances performance.
> 
> Signed-off-by: Allen Pais <allen.lkml@xxxxxxxxx>
> ---
>  drivers/net/ethernet/jme.c | 72 +++++++++++++++++++-------------------
>  drivers/net/ethernet/jme.h |  8 ++---
>  2 files changed, 40 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/net/ethernet/jme.c b/drivers/net/ethernet/jme.c
> index b06e24562973..b1a92b851b3b 100644
> --- a/drivers/net/ethernet/jme.c
> +++ b/drivers/net/ethernet/jme.c
> @@ -1141,7 +1141,7 @@ jme_dynamic_pcc(struct jme_adapter *jme)
>  
>  	if (unlikely(dpi->attempt != dpi->cur && dpi->cnt > 5)) {
>  		if (dpi->attempt < dpi->cur)
> -			tasklet_schedule(&jme->rxclean_task);
> +			queue_work(system_bh_wq, &jme->rxclean_bh_work);
>  		jme_set_rx_pcc(jme, dpi->attempt);
>  		dpi->cur = dpi->attempt;
>  		dpi->cnt = 0;
> @@ -1182,9 +1182,9 @@ jme_shutdown_nic(struct jme_adapter *jme)
>  }
>  
>  static void
> -jme_pcc_tasklet(struct tasklet_struct *t)
> +jme_pcc_bh_work(struct work_struct *work)
>  {
> -	struct jme_adapter *jme = from_tasklet(jme, t, pcc_task);
> +	struct jme_adapter *jme = from_work(jme, work, pcc_bh_work);
>  	struct net_device *netdev = jme->dev;
>  
>  	if (unlikely(test_bit(JME_FLAG_SHUTDOWN, &jme->flags))) {
> @@ -1282,9 +1282,9 @@ static void jme_link_change_work(struct work_struct *work)
>  		jme_stop_shutdown_timer(jme);
>  
>  	jme_stop_pcc_timer(jme);
> -	tasklet_disable(&jme->txclean_task);
> -	tasklet_disable(&jme->rxclean_task);
> -	tasklet_disable(&jme->rxempty_task);
> +	disable_work_sync(&jme->txclean_bh_work);
> +	disable_work_sync(&jme->rxclean_bh_work);
> +	disable_work_sync(&jme->rxempty_bh_work);
>  
>  	if (netif_carrier_ok(netdev)) {
>  		jme_disable_rx_engine(jme);
> @@ -1304,7 +1304,7 @@ static void jme_link_change_work(struct work_struct *work)
>  		rc = jme_setup_rx_resources(jme);
>  		if (rc) {
>  			pr_err("Allocating resources for RX error, Device STOPPED!\n");
> -			goto out_enable_tasklet;
> +			goto out_enable_bh_work;
>  		}
>  
>  		rc = jme_setup_tx_resources(jme);
> @@ -1326,22 +1326,22 @@ static void jme_link_change_work(struct work_struct *work)
>  		jme_start_shutdown_timer(jme);
>  	}
>  
> -	goto out_enable_tasklet;
> +	goto out_enable_bh_work;
>  
>  err_out_free_rx_resources:
>  	jme_free_rx_resources(jme);
> -out_enable_tasklet:
> -	tasklet_enable(&jme->txclean_task);
> -	tasklet_enable(&jme->rxclean_task);
> -	tasklet_enable(&jme->rxempty_task);
> +out_enable_bh_work:
> +	enable_and_queue_work(system_bh_wq, &jme->txclean_bh_work);
> +	enable_and_queue_work(system_bh_wq, &jme->rxclean_bh_work);
> +	enable_and_queue_work(system_bh_wq, &jme->rxempty_bh_work);

This will unconditionally schedule the rxempty_bh_work and is AFAICS a
different behavior WRT prior this patch.

In turn the rxempty_bh_work() will emit (almost unconditionally) the
'RX Queue Full!' message, so the change should be visibile to the user.

I think you should queue the work only if it was queued at cancel time.
You likely need additional status to do that.

Thanks,

Paolo