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Subject: Re: [PATCH net-next 4/7] net: ipa: ipa_stop() does not return an
 error
To:     Leon Romanovsky <leon@kernel.org>
Cc:     davem@davemloft.net, kuba@kernel.org, bjorn.andersson@linaro.org,
        evgreen@chromium.org, cpratapa@codeaurora.org,
        subashab@codeaurora.org, elder@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20210409180722.1176868-1-elder@linaro.org>
 <20210409180722.1176868-5-elder@linaro.org> <YHKYWCkPl5pucFZo@unreal>
From:   Alex Elder <elder@linaro.org>
Message-ID: <1f5c3d2c-f22a-ef5e-f282-fb2dec4479f3@linaro.org>
Date:   Sun, 11 Apr 2021 08:09:55 -0500
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On 4/11/21 1:34 AM, Leon Romanovsky wrote:
> On Fri, Apr 09, 2021 at 01:07:19PM -0500, Alex Elder wrote:
>> In ipa_modem_stop(), if the modem netdev pointer is non-null we call
>> ipa_stop().  We check for an error and if one is returned we handle
>> it.  But ipa_stop() never returns an error, so this extra handling
>> is unnecessary.  Simplify the code in ipa_modem_stop() based on the
>> knowledge no error handling is needed at this spot.
>>
>> Signed-off-by: Alex Elder <elder@linaro.org>
>> ---
>>  drivers/net/ipa/ipa_modem.c | 18 ++++--------------
>>  1 file changed, 4 insertions(+), 14 deletions(-)
> 
> <...>
> 
>> +	/* Stop the queue and disable the endpoints if it's open */
>>  	if (netdev) {
>> -		/* Stop the queue and disable the endpoints if it's open */
>> -		ret = ipa_stop(netdev);
>> -		if (ret)
>> -			goto out_set_state;
>> -
>> +		(void)ipa_stop(netdev);
> 
> This void casting is not needed here and in more general case sometimes
> even be seen as a mistake, for example if the returned attribute declared
> as __must_check.

I accept your point but I feel like it's sort of a 50/50 thing.

I think *not* checking an available return value is questionable
practice.  I'd really rather have a build option for a
"__need_not_check" tag and have "must_check" be the default.

The void cast here says "I know this returns a result, but I am
intentionally not checking it."  If it had been __must_check I
would certainly have checked it.  

That being said, I don't really care that much, so I'll plan
to post version 2, which will drop this cast (I'll probably
add a comment though).

Thanks.

					-Alex

> 
> Thanks
>