linux-kernel - Re: [PATCH v5 3/7] pci: Create pci_host_bridge before its associated bus in pci_create_root

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Message-id: <002401cf382d$3062aa50$9127fef0$%han@samsung.com>
Date:	Wed, 05 Mar 2014 13:41:35 +0900
From:	Jingoo Han <jg1.han@...sung.com>
To:	'Yijing Wang' <wangyijing@...wei.com>,
	'Liviu Dudau' <Liviu.Dudau@....com>
Cc:	'linux-pci' <linux-pci@...r.kernel.org>,
	'Bjorn Helgaas' <bhelgaas@...gle.com>,
	'Catalin Marinas' <Catalin.Marinas@....com>,
	'Will Deacon' <Will.Deacon@....com>,
	'linaro-kernel' <linaro-kernel@...ts.linaro.org>,
	'Benjamin Herrenschmidt' <benh@...nel.crashing.org>,
	'LKML' <linux-kernel@...r.kernel.org>,
	devicetree@...r.kernel.org,
	'LAKML' <linux-arm-kernel@...ts.infradead.org>,
	'Tanmay Inamdar' <tinamdar@....com>,
	'Arnd Bergmann' <arnd@...db.de>,
	'Jingoo Han' <jg1.han@...sung.com>
Subject: Re: [PATCH v5 3/7] pci: Create pci_host_bridge before its associated
 bus in pci_create_root_bus.

On Wednesday, March 05, 2014 12:48 PM, Yijing Wang wrote:
> On 2014/3/4 23:50, Liviu Dudau wrote:
> > Before commit 7b5436635800 the pci_host_bridge was created before the root bus.
> > As that commit has added a needless dependency on the bus for pci_alloc_host_bridge()
> > the creation order has been changed for no good reason. Revert the order of
> > creation as we are going to depend on the pci_host_bridge structure to retrieve the
> > domain number of the root bus.
> >
> > Signed-off-by: Liviu Dudau <Liviu.Dudau@....com>
> >
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 6e34498..78ccba0 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -505,7 +505,7 @@ static void pci_release_host_bridge_dev(struct device *dev)
> >  	kfree(bridge);
> >  }
> >
> > -static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
> > +static struct pci_host_bridge *pci_alloc_host_bridge(void)
> >  {
> >  	struct pci_host_bridge *bridge;
> >
> > @@ -514,7 +514,6 @@ static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
> >  		return NULL;
> >
> >  	INIT_LIST_HEAD(&bridge->windows);
> > -	bridge->bus = b;
> >  	return bridge;
> >  }
> >
> > @@ -1727,9 +1726,21 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> >  	char bus_addr[64];
> >  	char *fmt;
> >
> > +	bridge = pci_alloc_host_bridge();
> > +	if (!bridge)
> > +		return NULL;
> > +
> > +	bridge->dev.parent = parent;
> > +	bridge->dev.release = pci_release_host_bridge_dev;
> > +	error = pcibios_root_bridge_prepare(bridge);
> > +	if (error) {
> > +		kfree(bridge);
> > +		return NULL;
> 
> What about use goto err_out?

+1

I agree with your opinion.
It makes the code simpler.

Best regards,
Jingoo Han

> 
> > +	}
> > +
> >  	b = pci_alloc_bus();
> >  	if (!b)
> > -		return NULL;
> > +		goto err_out;
> >
> >  	b->sysdata = sysdata;
> >  	b->ops = ops;
> > @@ -1738,26 +1749,15 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> >  	if (b2) {
> >  		/* If we already got to this bus through a different bridge, ignore it */
> >  		dev_dbg(&b2->dev, "bus already known\n");
> > -		goto err_out;
> > +		goto err_bus_out;
> >  	}
> >
> > -	bridge = pci_alloc_host_bridge(b);
> > -	if (!bridge)
> > -		goto err_out;
> > -
> > -	bridge->dev.parent = parent;
> > -	bridge->dev.release = pci_release_host_bridge_dev;
> > +	bridge->bus = b;
> >  	dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
> > -	error = pcibios_root_bridge_prepare(bridge);
> > -	if (error) {
> > -		kfree(bridge);
> > -		goto err_out;
> > -	}
> > -
> >  	error = device_register(&bridge->dev);
> >  	if (error) {
> >  		put_device(&bridge->dev);
> > -		goto err_out;
> > +		goto err_bus_out;
> >  	}
> >  	b->bridge = get_device(&bridge->dev);
> >  	device_enable_async_suspend(b->bridge);
> > @@ -1814,8 +1814,10 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> >  class_dev_reg_err:
> >  	put_device(&bridge->dev);
> >  	device_unregister(&bridge->dev);
> > -err_out:
> > +err_bus_out:
> >  	kfree(b);
> > +err_out:
> > +	kfree(bridge);
> >  	return NULL;
> >  }
> >
> >

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