Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 3/3] ipmi:bt-bmc: Fix error handling and status check
To:     minyard@acm.org
Cc:     arnd@arndb.de, gregkh@linuxfoundation.org,
        openipmi-developer@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
References: <20200414141423.4968-1-tangbin@cmss.chinamobile.com>
 <20200414201832.GJ3587@minyard.net>
 <f5a848ae-d19f-5ab6-7c7d-2d0811fc174b@cmss.chinamobile.com>
 <20200418021441.GC6246@minyard.net>
From:   Tang Bin <tangbin@cmss.chinamobile.com>
Message-ID: <ab537b68-3116-747a-0e68-bbc5b3540d83@cmss.chinamobile.com>
Date:   Sat, 18 Apr 2020 15:23:54 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101
 Thunderbird/68.7.0
MIME-Version: 1.0
In-Reply-To: <20200418021441.GC6246@minyard.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Corey:

On 2020/4/18 10:14, Corey Minyard wrote:
> Sorry for the delay, I have had a lot of distractions.

No no no,  it's greatly appreciated  for your instruction. Thanks.

>
> The trouble is that the handling of bt_bmc->irq needs to be consistent.
> Either it needs to be negative if the irq allocation fails, or it needs
> to be zero if the irq allocation fails.  I think it needs to be negative
> because zero is a valid interrupt in some cases.
>
> Consider the following code:
>
>         bt_bmc_config_irq(bt_bmc, pdev);
>
>          if (bt_bmc->irq) {
>                  dev_info(dev, "Using IRQ %d\n", bt_bmc->irq);
>          } else {
>                  dev_info(dev, "No IRQ; using timer\n");
>                  timer_setup(&bt_bmc->poll_timer, poll_timer, 0);
>
> If bt_bmc->irq is negative (if platform_get_irq_optional() fails), it
> will say it's using the irq and won't start a timer and the driver won't
> work.  Then later (in your change below) it will try to stop the timer
> even though it's not running.
>
> If devm_request_irq() fails, then the interrupt is not set, but since
> bt_bmc->irq is most likely not zero, it will not start the timer and the
> driver won't work.
>
> You really need to set bt_bmc->irq negative if it fails.  And fix the
> check above to be if (bt_bmc->irq >= 0).

Got it. You are right, I am lacking in consideration here.


Thank you very much, I will send the v2.

Tang Bin

>
>
>