Re: [PATCH v4 07/10] IOMMU: propagate IOMMU Device-TLB flush error up to iommu_iotlb_flush{, _all} (leaf ones).

From: "Xu, Quan" <quan.xu@intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	"Wu, Feng" <feng.wu@intel.com>,
	"dario.faggioli@citrix.com" <dario.faggioli@citrix.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Julien Grall <julien.grall@arm.com>
Subject: Re: [PATCH v4 07/10] IOMMU: propagate IOMMU Device-TLB flush error up to iommu_iotlb_flush{, _all} (leaf ones).
Date: Wed, 11 May 2016 07:12:18 +0000	[thread overview]
Message-ID: <945CA011AD5F084CBEA3E851C0AB28894B8AC859@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <5732F60002000078000EA684@prv-mh.provo.novell.com>

On May 11, 2016 3:06 PM, Jan Beulich <JBeulich@suse.com> wrote:
> >>> On 11.05.16 at 08:47, <quan.xu@intel.com> wrote:
> > On May 10, 2016 5:07 PM, Jan Beulich <JBeulich@suse.com> wrote:
> >> >>> On 06.05.16 at 10:54, <quan.xu@intel.com> wrote:
> >> > --- a/xen/drivers/passthrough/vtd/iommu.c
> >> > +++ b/xen/drivers/passthrough/vtd/iommu.c
> >> > @@ -604,15 +604,15 @@ static int iommu_flush_iotlb(struct domain
> >> > *d,
> >> unsigned long gfn,
> >> >      return rc;
> >> >  }
> >> >
> >> > -static void iommu_flush_iotlb_page(struct domain *d, unsigned long
> gfn,
> >> > -                                   unsigned int page_count)
> >> > +static int iommu_flush_iotlb_page(struct domain *d, unsigned long gfn,
> >> > +                                  unsigned int page_count)
> >> >  {
> >> > -    iommu_flush_iotlb(d, gfn, 1, page_count);
> >> > +    return iommu_flush_iotlb(d, gfn, 1, page_count);
> >> >  }
> >> >
> >> > -static void iommu_flush_iotlb_all(struct domain *d)
> >> > +static int iommu_flush_iotlb_all(struct domain *d)
> >> >  {
> >> > -    iommu_flush_iotlb(d, INVALID_GFN, 0, 0);
> >> > +    return iommu_flush_iotlb(d, INVALID_GFN, 0, 0);
> >> >  }
> >>
> >> As already indicated in a reply to an earlier patch, despite what was
> >> said on the earlier version I think we should have __must_check here
> >
> > If the static one is initialized for .callback, is it really necessary
> > to add __must_check here?
> > I check it with compiler, and it is ok when I didn't add __must_check here.
> 
> Without you telling us what exactly you checked, I can't respond to this.
> Extending from the reply just sent to patch 3(?) and for the avoidance of
> doubt, you now obviously also need to __must_check-annotate the function
> pointer (to match the desire of wanting to never lose such an annotation on
> the way back up the call tree).
> 

I checked -- without __must_check for iommu_flush_iotlb_page() / iommu_flush_iotlb_all().

> > If yes, I'll add __must_check for ARM one as well.
> 
> Of course.
> 
Got it.

Quan

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