RE: [PATCH v1] net: usb: Convert tasklet API to new bottom half workqueue mechanism

Miao, Jun
2025-06-14T10:59:07Z

>
>Hi,
>
>On 2025-06-13 at 12:43:18, Jun Miao (jun.miao@intel.com) 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 usbnet driver. This transition ensures
>> compatibility with the latest design and enhances performance.
>>
>> Signed-off-by: Jun Miao <jun.miao@intel.com>
>> ---
>> drivers/net/usb/usbnet.c | 36 ++++++++++++++++++------------------
>> include/linux/usb/usbnet.h | 2 +-
>> 2 files changed, 19 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index
>> c04e715a4c2a..566127b4e0ba 100644
>> --- a/drivers/net/usb/usbnet.c
>> +++ b/drivers/net/usb/usbnet.c
>> @@ -461,7 +461,7 @@ static enum skb_state defer_bh(struct usbnet *dev,
>> struct sk_buff *skb,
>>
>> __skb_queue_tail(&dev->done, skb);
>> if (dev->done.qlen == 1)
>> - tasklet_schedule(&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> spin_unlock(&dev->done.lock);
>> spin_unlock_irqrestore(&list->lock, flags);
>> return old_state;
>> @@ -549,7 +549,7 @@ static int rx_submit (struct usbnet *dev, struct urb *urb,
>gfp_t flags)
>> default:
>> netif_dbg(dev, rx_err, dev->net,
>> "rx submit, %d\n", retval);
>> - tasklet_schedule (&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> break;
>> case 0:
>> __usbnet_queue_skb(&dev->rxq, skb, rx_start); @@ -
>709,7 +709,7 @@
>> void usbnet_resume_rx(struct usbnet *dev)
>> num++;
>> }
>>
>> - tasklet_schedule(&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>>
>> netif_dbg(dev, rx_status, dev->net,
>> "paused rx queue disabled, %d skbs requeued\n", num); @@ -
>778,7
>> +778,7 @@ void usbnet_unlink_rx_urbs(struct usbnet *dev) {
>> if (netif_running(dev->net)) {
>> (void) unlink_urbs (dev, &dev->rxq);
>> - tasklet_schedule(&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> }
>> }
>> EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
>> @@ -861,14 +861,14 @@ int usbnet_stop (struct net_device *net)
>> /* deferred work (timer, softirq, task) must also stop */
>> dev->flags = 0;
>> timer_delete_sync(&dev->delay);
>> - tasklet_kill(&dev->bh);
>> + disable_work_sync(&dev->bh_work);
>> cancel_work_sync(&dev->kevent);
>>
>> /* We have cyclic dependencies. Those calls are needed
>> * to break a cycle. We cannot fall into the gaps because
>> * we have a flag
>> */
>> - tasklet_kill(&dev->bh);
>> + disable_work_sync(&dev->bh_work);
>> timer_delete_sync(&dev->delay);
>> cancel_work_sync(&dev->kevent);
>>
>> @@ -955,7 +955,7 @@ int usbnet_open (struct net_device *net)
>> clear_bit(EVENT_RX_KILL, &dev->flags);
>>
>> // delay posting reads until we're fully open
>> - tasklet_schedule (&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> if (info->manage_power) {
>> retval = info->manage_power(dev, 1);
>> if (retval < 0) {
>> @@ -1123,7 +1123,7 @@ static void __handle_link_change(struct usbnet *dev)
>> */
>> } else {
>> /* submitting URBs for reading packets */
>> - tasklet_schedule(&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> }
>>
>> /* hard_mtu or rx_urb_size may change during link change */ @@
>> -1198,11 +1198,11 @@ usbnet_deferred_kevent (struct work_struct *work)
>> } else {
>> clear_bit (EVENT_RX_HALT, &dev->flags);
>> if (!usbnet_going_away(dev))
>> - tasklet_schedule(&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> }
>> }
>>
>> - /* tasklet could resubmit itself forever if memory is tight */
>> + /* workqueue could resubmit itself forever if memory is tight */
>> if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
>> struct urb *urb = NULL;
>> int resched = 1;
>> @@ -1224,7 +1224,7 @@ usbnet_deferred_kevent (struct work_struct
>> *work)
>> fail_lowmem:
>> if (resched)
>> if (!usbnet_going_away(dev))
>> - tasklet_schedule(&dev->bh);
>> + queue_work(system_bh_wq, &dev-
>>bh_work);
>> }
>> }
>>
>> @@ -1325,7 +1325,7 @@ void usbnet_tx_timeout (struct net_device *net,
>unsigned int txqueue)
>> struct usbnet *dev = netdev_priv(net);
>>
>> unlink_urbs (dev, &dev->txq);
>> - tasklet_schedule (&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> /* this needs to be handled individually because the generic layer
>> * doesn't know what is sufficient and could not restore private
>> * information if a remedy of an unconditional reset were used.
>> @@ -1547,7 +1547,7 @@ static inline void usb_free_skb(struct sk_buff
>> *skb)
>>
>>
>> /*--------------------------------------------------------------------
>> -----*/
>>
>> -// tasklet (work deferred from completions, in_irq) or timer
>> +// workqueue (work deferred from completions, in_irq) or timer
>>
>> static void usbnet_bh (struct timer_list *t) { @@ -1601,16 +1601,16
>> @@ static void usbnet_bh (struct timer_list *t)
>> "rxqlen %d --> %d\n",
>> temp, dev->rxq.qlen);
>> if (dev->rxq.qlen < RX_QLEN(dev))
>> - tasklet_schedule (&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> }
>> if (dev->txq.qlen < TX_QLEN (dev))
>> netif_wake_queue (dev->net);
>> }
>> }
>>
>> -static void usbnet_bh_tasklet(struct tasklet_struct *t)
>> +static void usbnet_bh_workqueue(struct work_struct *work)
>> {
>> - struct usbnet *dev = from_tasklet(dev, t, bh);
>> + struct usbnet *dev = from_work(dev, work, bh_work);
>>
>> usbnet_bh(&dev->delay);
>> }
>> @@ -1742,7 +1742,7 @@ usbnet_probe (struct usb_interface *udev, const
>struct usb_device_id *prod)
>> skb_queue_head_init (&dev->txq);
>> skb_queue_head_init (&dev->done);
>> skb_queue_head_init(&dev->rxq_pause);
>> - tasklet_setup(&dev->bh, usbnet_bh_tasklet);
>> + INIT_WORK (&dev->bh_work, usbnet_bh_workqueue);
>
>WARNING: space prohibited between function name and open parenthesis '('
>#160: FILE: drivers/net/usb/usbnet.c:1745:
>+ INIT_WORK (&dev->bh_work, usbnet_bh_workqueue);
>
>total: 0 errors, 1 warnings, 0 checks, 144 lines checked
>
>checkpatch warning here please fix this minor thing and resubmit.

Indeed, there are more spaces. Fixed and repost v2 again.
Thank you for your care and patience again.
Jun Miao

>
>Thanks,
>Sundeep
>
>> INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
>> init_usb_anchor(&dev->deferred);
>> timer_setup(&dev->delay, usbnet_bh, 0); @@ -1971,7 +1971,7 @@ int
>> usbnet_resume (struct usb_interface *intf)
>>
>> if (!(dev->txq.qlen >= TX_QLEN(dev)))
>> netif_tx_wake_all_queues(dev->net);
>> - tasklet_schedule (&dev->bh);
>> + queue_work(system_bh_wq, &dev->bh_work);
>> }
>> }
>>
>> diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
>> index 0b9f1e598e3a..208682f77179 100644
>> --- a/include/linux/usb/usbnet.h
>> +++ b/include/linux/usb/usbnet.h
>> @@ -58,7 +58,7 @@ struct usbnet {
>> unsigned interrupt_count;
>> struct mutex interrupt_mutex;
>> struct usb_anchor deferred;
>> - struct tasklet_struct bh;
>> + struct work_struct bh_work;
>>
>> struct work_struct kevent;
>> unsigned long flags;
>> --
>> 2.32.0
>>