Re: [PATCH 2/3] r8152: Retry register reads/writes

Hi,

On Wed, Sep 27, 2023 at 6:43 AM Alan Stern [off-list ref] wrote:

On Tue, Sep 26, 2023 at 02:27:27PM -0700, Douglas Anderson wrote:

quoted

+
+static
+int r8152_control_msg(struct usb_device *udev, unsigned int pipe, __u8 request,
+                   __u8 requesttype, __u16 value, __u16 index, void *data,
+                   __u16 size, const char *msg_tag)
+{
+     int i;
+     int ret;
+
+     for (i = 0; i < REGISTER_ACCESS_TRIES; i++) {
+             ret = usb_control_msg(udev, pipe, request, requesttype,
+                                   value, index, data, size,
+                                   USB_CTRL_GET_TIMEOUT);
+
+             /* No need to retry or spam errors if the USB device got
+              * unplugged; just return immediately.
+              */
+             if (udev->state == USB_STATE_NOTATTACHED)
+                     return ret;

Rather than testing udev->state, it would be better to check whether
ret == -ENODEV.  udev->state is meant primarily for use by the USB core
and it's subject to races.

Thanks for looking my patch over!

Happy to change this to -ENODEV. In my early drafts of this patch I
looked at -ENODEV but I noticed that other places in the driver were
checking `udev->state == USB_STATE_NOTATTACHED` so I changed it. In
reality I think for this code path it doesn't matter a whole lot. The
only thing it's doing is avoiding a few extra retries and avoiding a
log message. :-)

I'll wait a few more days to see if there is any other feedback on
this series and then send a new version with that addressed. If
someone needs me to send a new version sooner then please yell.

-Doug