linux-kernel - Re: [PATCH v2] ipmi:bt-bmc: Fix error handling and status check

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Date:   Mon, 4 May 2020 08:16:05 -0500
From:   Corey Minyard <minyard@....org>
To:     Tang Bin <tangbin@...s.chinamobile.com>
Cc:     arnd@...db.de, gregkh@...uxfoundation.org,
        openipmi-developer@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ipmi:bt-bmc: Fix error handling and status check

On Sun, Apr 19, 2020 at 02:29:26PM +0800, Tang Bin wrote:
> Hi, Corey:
> 
> On 2020/4/18 21:49, Corey Minyard wrote:
> > On Sat, Apr 18, 2020 at 04:02:29PM +0800, Tang Bin wrote:
> > > If the function platform_get_irq() failed, the negative
> > > value returned will not be detected here. So fix error
> > > handling in bt_bmc_config_irq(). And if devm_request_irq()
> > > failed, 'bt_bmc->irq' is assigned to zero maybe redundant,
> > > it may be more suitable for using the correct negative values
> > > to make the status check in the function bt_bmc_remove().
> > You need to mention changing platform_get_irq to
> > platform_get_irq_optional in the header.
> > 
> > Another comment inline below.
> > 
> > Otherwise, this looks good.
> 
> Got it. The v3 will be as follows：
> 
> If the function platform_get_irq() failed, the negative value
> 
> returned will not be detected here. So fix error handling in
> 
> bt_bmc_config_irq(). And in the function bt_bmc_probe(),
> 
> when get irq failed, it will print error message. So use
> 
> platform_get_irq_optional() to simplify code. Finally in the
> 
> function bt_bmc_remove() should make the right status
> 
> check if get irq failed.
> 
> > 
> > You need to set this to rc.  Otherwise it will remain the interrupt
> > number assigned by platform_get_irq_optional().
> 
> Yes, I think you are right. I'm not as considerate as you. Thank you for
> your instruction.
> 
> When get irq failed, the 'bt_bmc->irq' is negative; when request irq failed,
> the 'bt_bmc->irq = 0' is right.
> 
> So 'bt_bmc->irq <= 0' means irq failed.

Sorry, I missed your question here and was waiting for v3.

Well, we want bt_bmc->irq < 0 to mean the irq request failed.

> 
> Now let me rearrange the logic here:
> 
>     In bt_bmc_probe():
> 
>         bt_bmc_config_irq(bt_bmc, pdev);
> 
>         if (bt_bmc->irq > 0) {

Should be >= 0.

> 
>         }
> 
> 
>     In bt_bmc_remove():
> 
>         if (bt_bmc->irq <= 0)
>             del_timer_sync(&bt_bmc->poll_timer);

Should be < 0.  But other than that, I think it's correct.

-corey

> 
> 
> If you think this logic is correct, I'll submit v3.
> 
> Thanks,
> 
> Tang Bin
> 
> > 
> > 
> > 
> > 
> 
>