linux-kernel - Re: [PATCH v4 1/4] PCI: Introduce pcim_alloc_irq

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Message-ID: <20210223141435.GA912403@nuc8i5>
Date:   Tue, 23 Feb 2021 22:14:35 +0800
From:   Dejin Zheng <zhengdejin5@...il.com>
To:     Robert Richter <rric@...nel.org>
Cc:     corbet@....net, jarkko.nikula@...ux.intel.com,
        andriy.shevchenko@...ux.intel.com, mika.westerberg@...ux.intel.com,
        bhelgaas@...gle.com, wsa@...nel.org, linux-doc@...r.kernel.org,
        linux-i2c@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/4] PCI: Introduce pcim_alloc_irq_vectors()

On Tue, Feb 23, 2021 at 09:02:54AM +0100, Robert Richter wrote:
> On 22.02.21 23:14:15, Dejin Zheng wrote:
> > On Mon, Feb 22, 2021 at 11:56:08AM +0100, Robert Richter wrote:
> > > On 20.02.21 00:46:49, Dejin Zheng wrote:
> > > > > On 18.02.21 23:04:55, Dejin Zheng wrote:
> > > 
> > > > > > +	if (!dr || !dr->enabled)
> > > > here checks whether the pci device is enabled.
> > > 
> > > What is the purpose of this? The device "is_managed" or not.
> > >
> > The device is managed or not by check whether "dr" is NULL. And
> > check the "dr->enabled" is for the PCI device enable. I think it
> > may not make sense to apply for irq vectors when PCI device is not
> > enabled.
> 
> I don't see how a disabled device affects in any way the release of
> the irq vectors during device removal. dr is always non-null in case
> the device is managed, a check isn't needed for that.
>
Yes, the disabled device does not affect release irq vectors, But
the disabled device affects apply for irq vectors, It is wrong to apply
for the irq vectors when the device is not enabled. Add this check can
facilitate developers to find problems as soon as possible.

> -Robert