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Date: Thu, 21 Dec 2023 11:51:24 +0100
From: Lukas Wunner <lukas@wunner.de>
To: Ethan Zhao <haifeng.zhao@linux.intel.com>
Cc: bhelgaas@google.com, baolu.lu@linux.intel.com, dwmw2@infradead.org,
	will@kernel.org, robin.murphy@arm.com, linux-pci@vger.kernel.org,
	iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
	Haorong Ye <yehaorong@bytedance.com>
Subject: Re: [PATCH 1/2] PCI: make pci_dev_is_disconnected() helper public
 for other drivers
Message-ID: <20231221105124.GC12714@wunner.de>
References: <20231213034637.2603013-1-haifeng.zhao@linux.intel.com>
 <20231213034637.2603013-2-haifeng.zhao@linux.intel.com>
 <20231213104930.GB31964@wunner.de>
 <31bd82b6-6f7e-4dc4-8cbb-46fa806d699f@linux.intel.com>
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On Thu, Dec 14, 2023 at 08:58:49AM +0800, Ethan Zhao wrote:
> On 12/13/2023 6:49 PM, Lukas Wunner wrote:
> > On Tue, Dec 12, 2023 at 10:46:36PM -0500, Ethan Zhao wrote:
> > > move pci_dev_is_disconnected() from driver/pci/pci.h to public
> > > include/linux/pci.h for other driver's reference.
> > > no function change.
> > 
> > That's merely a prose description of the code.  A reader can already
> > see from the code what it's doing.  You need to explain the *reason*
> > for the change instead.  E.g.:  "Make pci_dev_is_disconnected() public
> > so that it can be called from $DRIVER to speed up hot removal
> > handling which may otherwise take seconds because of $REASONS."
> 
> Yup, why I made it public. then how about
> 
> "Make pci_dev_is_disconnected() public so that it can be called from
> Intel vt-d driver to check the device's hotplug removal state when
> issue devTLB flush request."

Much better.

You may optionally want to point out the location of the file in the
source tree because not everyone may be familiar where to find the
"Intel vt-d driver".  Also, not every reader may know where issuing
of devTLB flush requests occurs, so it might make sense to name the
function where that happens.  Finally, it is common to adhere to terms
used in the PCIe Base Spec in commit messages, so "ATC Invalidate Request"
might be preferable to "devTLB flush request".

Thanks,

Lukas