On Thu, 2013-08-22 at 15:52 +0800, Wei Yang wrote: > On Thu, Aug 22, 2013 at 05:23:34PM +1000, Alexey Kardashevskiy wrote: > >On 08/19/2013 11:55 AM, Wei Yang wrote: > >> On Mon, Aug 19, 2013 at 11:39:49AM +1000, Alexey Kardashevskiy wrote: > >>> On 08/19/2013 11:29 AM, Wei Yang wrote: > >>>> On Fri, Aug 16, 2013 at 08:15:36PM +1000, Alexey Kardashevskiy wrote: > >>>>> On 08/16/2013 08:08 PM, Wei Yang wrote: > >>>>>> --- > >>>>>> arch/powerpc/kernel/iommu.c | 3 ++- > >>>>>> 1 files changed, 2 insertions(+), 1 deletions(-) > >>>>>> > >>>>>> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c > >>>>>> index b20ff17..5abf7c3 100644 > >>>>>> --- a/arch/powerpc/kernel/iommu.c > >>>>>> +++ b/arch/powerpc/kernel/iommu.c > >>>>>> @@ -1149,7 +1149,8 @@ static int iommu_bus_notifier(struct > >>>>>> notifier_block *nb, > >>>>>> case BUS_NOTIFY_ADD_DEVICE: > >>>>>> return iommu_add_device(dev); > >>>>>> case BUS_NOTIFY_DEL_DEVICE: > >>>>>> - iommu_del_device(dev); > >>>>>> + if (dev->iommu_group) > >>>>>> + iommu_del_device(dev); > >>>>>> return 0; > >>>>>> default: > >>>>>> return 0; > >>>>>> > >>>>> > >>>>> This one seems redundant, no? > >>>> > >>>> Sorry for the late. > >>>> > >>>> Yes, these two patches have the same purpose to guard the system, while > >>>> in two > >>>> different places. One is in powernv platform, the other is in the > >>>> generic iommu > >>>> driver. > >>>> > >>>> The one in powernv platform is used to correct the original logic. > >>>> > >>>> The one in generic iommu driver is to keep system safe in case other > >>>> platform to > >>>> call iommu_group_remove_device() without the check. > >>> > >>> > >>> But I am moving bus notifier to powernv code (posted a patch last week, > >>> otherwise Freescale's IOMMU conflicted) so this won't be the case. > >> > >> Yes, I see the patch. > >> > >> This means other platforms, besides powernv, will check the > >> dev->iommu_group > >> before remove the device? This would be a convention? > >> > >> If this is the case, the second patch is enough. We don't need to check it > >> in > >> generic iommu driver. > >> > >> Since I am not very familiar with the code convention, I post these two > >> patches together. This doesn't mean I need to push both of them. Your > >> comments > >> are welcome, lets me understand which one is more suitable in this case. > > > > > >Ok. So. I included the check in the bus notifier which I moved to powernv > >platform, I guess I'll repost the series soon. > > Thanks, this check will guard the powernv platform. > > > > >Good luck with pushing the fix for drivers/iommu/iommu.c :) > > > > Alex, > > Sorry for not including you in the very beginning, which may spend you more > efforts to track previous mails in this thread. > > Do you think it is reasonable to check the dev->iommu_group in > iommu_group_remove_device()? Or we can count on the bus notifier to check it? > > Welcome your suggestions~
I don't really see the point of patch 1/2. iommu_group_remove_device() is specifically to remove a device from an iommu_group, so why would you call it on a device that's not part of an iommu_group. If you want to avoid testing dev->iommu_group, then implement the .remove_device callback rather than using the notifier. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
