Hi, Gary and Sohil,
On Tue, 2018-04-17 at 13:38 -0400, Hook, Gary wrote:
> On 4/13/2018 8:08 PM, Mehta, Sohil wrote:
> >
> > On Fri, 2018-04-06 at 08:17 -0500, Gary R Hook wrote:
> > >
> > >
> > > +
> > > +void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
> > > +{
> > > + char name[MAX_NAME_LEN + 1];
> > > + struct dentry *d_top;
> > > +
> > > + if (!debugfs_initialized())
> > Probably not needed.
> Right.
When will this check is needed?
IMO, this function is to check debugfs ready status before we want to
use debugfs. I just want to understand when we should use
debugfs_initialized();
Thanks.
Shunyong.
>
> >
> >
> > >
> > > + return;
> > > +
> > > + mutex_lock(&amd_iommu_debugfs_lock);
> > > + if (!amd_iommu_debugfs) {
> > > + d_top = iommu_debugfs_setup();
> > > + if (d_top)
> > > + amd_iommu_debugfs =
> > > debugfs_create_dir("amd", d_top);
> > > + }
> > > + mutex_unlock(&amd_iommu_debugfs_lock);
> >
> > You can do the above only once if you iterate over the IOMMUs here
> > instead of doing it in amd_iommu_init.
> I'm not sure it matters, given the finite number of IOMMUs in a
> system,
> and the fact that this work is done exactly once. However, removal of
> a
> lock is fine thing, so I'll move this around.
>
> >
> >
> > >
> > > + if (amd_iommu_debugfs) {
> > > + snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu-
> > > >
> > > > index);
> > > + iommu->debugfs = debugfs_create_dir(name,
> > > + amd_iommu_de
> > > bugf
> > > s);
> > > + if (!iommu->debugfs) {
> > > + debugfs_remove_recursive(amd_iommu_debug
> > > fs);
> > > + amd_iommu_debugfs = NULL;
> > > + }
> > > + }
> > > +}
> > -Sohil
> >
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