On 25.10.2024 16:14:03, Ming Yu wrote:
> Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> 於 2024年10月24日 週四 下午11:34寫道：
> >
> > On 24.10.2024 17:20:57, Marc Kleine-Budde wrote:
> >
> > [...]
> >
> > > > + nct6694->cmd_buffer = devm_kcalloc(dev, CMD_PACKET_SZ,
> > > > + sizeof(unsigned char), GFP_KERNEL);
> > > > + if (!nct6694->cmd_buffer)
> > > > + return -ENOMEM;
> > > > + nct6694->rx_buffer = devm_kcalloc(dev, MAX_PACKET_SZ,
> > > > + sizeof(unsigned char), GFP_KERNEL);
> > > > + if (!nct6694->rx_buffer)
> > > > + return -ENOMEM;
> > > > + nct6694->tx_buffer = devm_kcalloc(dev, MAX_PACKET_SZ,
> > > > + sizeof(unsigned char), GFP_KERNEL);
> > > > + if (!nct6694->tx_buffer)
> > > > + return -ENOMEM;
> > > > + nct6694->int_buffer = devm_kcalloc(dev, MAX_PACKET_SZ,
> > > > + sizeof(unsigned char), GFP_KERNEL);
> > > > + if (!nct6694->int_buffer)
> > > > + return -ENOMEM;
> > > > +
> > > > + nct6694->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> > > > + if (!nct6694->int_in_urb) {
> > > > + dev_err(&udev->dev, "Failed to allocate INT-in urb!\n");
> > > > + return -ENOMEM;
> > > > + }
> > > > +
> > > > + /* Bulk pipe maximum packet for each transaction */
> > > > + bulk_pipe = usb_sndbulkpipe(udev, BULK_OUT_ENDPOINT);
> > > > + nct6694->maxp = usb_maxpacket(udev, bulk_pipe);
> > > > +
> > > > + mutex_init(&nct6694->access_lock);
> > > > + nct6694->udev = udev;
> > > > + nct6694->timeout = URB_TIMEOUT; /* Wait until urb complete */
> > > > +
> > > > + INIT_LIST_HEAD(&nct6694->handler_list);
> > > > + spin_lock_init(&nct6694->lock);
> > > > +
> > > > + usb_fill_int_urb(nct6694->int_in_urb, udev, pipe,
> > > > + nct6694->int_buffer, maxp, usb_int_callback,
> > > > + nct6694, int_endpoint->bInterval);
> > > > + ret = usb_submit_urb(nct6694->int_in_urb, GFP_KERNEL);
> > > > + if (ret)
> > > > + goto err_urb;
> > > > +
> > > > + dev_set_drvdata(&udev->dev, nct6694);
> > > > + usb_set_intfdata(iface, nct6694);
> > > > +
> > > > + ret = mfd_add_hotplug_devices(&udev->dev, nct6694_dev,
> > > > + ARRAY_SIZE(nct6694_dev));
> > > > + if (ret) {
> > > > + dev_err(&udev->dev, "Failed to add mfd's child device\n");
> > > > + goto err_mfd;
> > > > + }
> > > > +
> > > > + nct6694->async_workqueue = alloc_ordered_workqueue("asyn_workqueue", 0);
> > >
> > > Where is the async_workqueue used?
> >
> > Sorry - it's used in the driver, which live in separate directories -
> > you can ignore this comment.
> >
> > But then the question comes up, it looks racy to _first_ add the devices
> > and _then_ the workqueue.
> Excuse me, I'm a bit confused. Is there anything I need to
> improve on?
It looks racy to _first_ add the devices and _then_ the workqueue.
So the obvious solution is to allocate the worklist first and then add
the devices.
regards,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung Nürnberg | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
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