linux-kernel - Re: [PATCH v4 08/12] PCI: Introduce /sys/bus/pci/devices/.../remove

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090319204646.GB8790@ldl.fc.hp.com>
Date:	Thu, 19 Mar 2009 14:46:46 -0600
From:	Alex Chiang <achiang@...com>
To:	Trent Piepho <xyzzy@...akeasy.org>
Cc:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>,
	jbarnes@...tuousgeek.org, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 08/12] PCI: Introduce /sys/bus/pci/devices/.../remove

* Trent Piepho <xyzzy@...akeasy.org>:
> On Thu, 19 Mar 2009, Alex Chiang wrote:
> > * Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>:
> > >> +	pci_remove_bus_device(pdev);
> > >> +	if (bridge && list_empty(&pdev->bus->devices))
> > >> +		pci_remove_bus(pdev->bus);
> > >
> > > I cannot understand the above two lines. Could you explain
> > > what it intend?
> >
> > If the user says:
> >
> > 	echo 1 > /sys/bus/pci/devices/.../remove
> >
> > And that device is a bridge, then we need to specifically call
> > pci_remove_bus as well, to actually remove the bus itself.
> > Without it, pci_bus_remove_device() will remove all of its
> > children (and subordinate buses) in a depth-first manner, but we
> > will never actually remove the bus that the user specified.
> 
> Did this end up being the source of the pci resource assignment warnings
> that were produced when re-adding a bridge that was removed?

I think that was one reason. I found that it was necessary during
multiple remove/rescan cycles; after the 2nd rescan, we had a
stale pci_bus hanging around that was manifesting itself as a
sysfs issue.

The other thing that Kenji found was in pci_setup_bridge(), where
we don't want to initialize the BARs if the bridge has already
been added.

Thanks.

/ac

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/