linux-kernel - Re: [RFC PATCH] PCI/portdrv: No need to call pci_disable

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Message-ID: <20200910202106.GA811000@bjorn-Precision-5520>
Date:   Thu, 10 Sep 2020 15:21:06 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Xuefeng Li <lixuefeng@...ngson.cn>,
        Huacai Chen <chenhc@...ote.com>
Subject: Re: [RFC PATCH] PCI/portdrv: No need to call pci_disable_device()
 during shutdown

[+cc Huacai]

On Thu, Sep 10, 2020 at 02:41:39PM -0500, Bjorn Helgaas wrote:
> On Sat, Sep 05, 2020 at 04:33:26PM +0800, Tiezhu Yang wrote:
> > After commit 745be2e700cd ("PCIe: portdrv: call pci_disable_device
> > during remove") and commit cc27b735ad3a ("PCI/portdrv: Turn off PCIe
> > services during shutdown"), it also calls pci_disable_device() during
> > shutdown, this seems unnecessary, so just remove it.
> 
> I would like to get rid of the portdrv completely by folding its
> functionality into the PCI core itself, so there would be no portdrv
> probe or remove.
> 
> Does this solve a problem?  If not, I'm inclined to just leave it
> as-is for now.  But if it fixes something, we should do the fix, of
> course.

This looks awfully similar to [1], so I guess we *do* need to do
something here.  I'll respond there since it has more details.

[1] https://lore.kernel.org/r/1596268180-9114-1-git-send-email-chenhc@lemote.com

> > Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> > ---
> >  drivers/pci/pcie/portdrv_core.c |  1 -
> >  drivers/pci/pcie/portdrv_pci.c  | 14 +++++++++++++-
> >  2 files changed, 13 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> > index 50a9522..1991aca 100644
> > --- a/drivers/pci/pcie/portdrv_core.c
> > +++ b/drivers/pci/pcie/portdrv_core.c
> > @@ -491,7 +491,6 @@ void pcie_port_device_remove(struct pci_dev *dev)
> >  {
> >  	device_for_each_child(&dev->dev, NULL, remove_iter);
> >  	pci_free_irq_vectors(dev);
> > -	pci_disable_device(dev);
> >  }
> >  
> >  /**
> > diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
> > index 3a3ce40..cab37a8 100644
> > --- a/drivers/pci/pcie/portdrv_pci.c
> > +++ b/drivers/pci/pcie/portdrv_pci.c
> > @@ -143,6 +143,18 @@ static void pcie_portdrv_remove(struct pci_dev *dev)
> >  	}
> >  
> >  	pcie_port_device_remove(dev);
> > +	pci_disable_device(dev);
> > +}
> > +
> > +static void pcie_portdrv_shutdown(struct pci_dev *dev)
> > +{
> > +	if (pci_bridge_d3_possible(dev)) {
> > +		pm_runtime_forbid(&dev->dev);
> > +		pm_runtime_get_noresume(&dev->dev);
> > +		pm_runtime_dont_use_autosuspend(&dev->dev);
> > +	}
> > +
> > +	pcie_port_device_remove(dev);
> >  }
> >  
> >  static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
> > @@ -211,7 +223,7 @@ static struct pci_driver pcie_portdriver = {
> >  
> >  	.probe		= pcie_portdrv_probe,
> >  	.remove		= pcie_portdrv_remove,
> > -	.shutdown	= pcie_portdrv_remove,
> > +	.shutdown	= pcie_portdrv_shutdown,
> >  
> >  	.err_handler	= &pcie_portdrv_err_handler,
> >  
> > -- 
> > 2.1.0
> >