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SubjectRe: [PATCH] staging: rtl8188eu: Remove an unused variable and some lines of code
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On Friday, July 2, 2021 10:35:21 AM CEST Dan Carpenter wrote:
> On Fri, Jul 02, 2021 at 10:48:40AM +0300, Dan Carpenter wrote:
> > On Thu, Jul 01, 2021 at 04:47:07PM +0200, Fabio M. De Francesco wrote:
> > > Remove set but unused iw_operation_mode[]. Remove all the lines of
> > > code from the function rtw_wx_set_rate, except the "return 0;" line
> > > to not break userland code that somewhat uses this IOCTL.
> > >
> > > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> > > [...]
> >

Dear Dan,

> > Just delete this whole file. It doesn't do anything now.
>
> Sorry, I meant function, not file. *chortle*. :P

No worries, it is clear it was unintended.

Back to the function... As you may suspect :-) I know practically nothing
neither of Linux device drivers or of whatever else kernel, so I take your
words for good. ASAP, I'll send a v2 of this patch.

However, I usually like to understand what I make (just for fun and... more).

That rtw_wx_set_rate() is the implementation of the SIOCSIWRATE IOCTL command.
I hope that I have not misunderstood it, have I?

However, we know that this function does practically nothing and then simply
returns 0 to the user. That's exactly the reason why I deleted all its lines
(except one).

If I am a user of that command I get a "success" return code (0) and I don't
notice that it won't be able to set the bit rate. However everything should
still keep running (I suppose using the default bit rate of the hardware; who
really knows?).

Now it's time for two questions:

1) what happens if that command is used by some users that (hopelessly) expect
the function to set the bit rate? I mean: if the function is not anymore in
the list of the IOCTL commands of the rtw_handlers array will still the user
program compile, link, and don't crash at runtime?

2) how should I delete the association of SIOCSIWRATE with rtw_wx_set_rate()
in the rtw_handlers array?
- delete the entry and shift the array one position up?
- set the SIOCSIWRATE entry to NULL?

Regards,

Fabio
>
> regards,
> dan carpenter



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