On Sun, Aug 22, 2021 at 03:21:30PM +0200, Fabio M. De Francesco wrote:

On Sunday, August 22, 2021 2:39:34 PM CEST Greg KH wrote:

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On Sun, Aug 22, 2021 at 03:10:56PM +0300, Pavel Skripkin wrote:

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On 8/22/21 1:59 PM, Fabio M. De Francesco wrote:

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On Sunday, August 22, 2021 12:09:29 PM CEST Pavel Skripkin wrote:

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So, it's up to the callers to test if (!_rtw_read*()) and then act
accordingly. If they get 0 they should know how to handle the errors.

Yes, but _rtw_read*() == 0 indicates 2 states:
	1. Error on transfer side
	2. Actual register value is 0

That's not a good design, it should be fixed.  Note there is the new
usb_control_msg_recv() function which should probably be used instead
here, to prevent this problem from happening.

I think that no functions should return 0 for signaling FAILURE. If I'm not 
wrong, the kernel quite always prefers to return 0 on SUCCESS and <0 on 
FAILURE. Why don't you just fix this?

Fix what specifically here?  The usb_control_msg() call?  If so, that is
why usb_control_msg_recv() was created, as sometimes you do want to do
what usb_control_msg() does today (see the users in the USB core today
for examples of why this is needed.)

In general, yes, 0 is success, negative is error, and positive is the
number of bytes read/written.

Anyway, let's see the second round of patches here before continuing
this thread...

thanks,

greg k-h