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Date:   Wed, 18 Jan 2023 11:15:29 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     "Tian, Kevin" <kevin.tian@intel.com>
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Subject: Re: [PATCH 6/8] iommu/intel: Add a gfp parameter to
 alloc_pgtable_page()
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On Wed, Jan 18, 2023 at 01:18:18AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Tuesday, January 17, 2023 9:30 PM
> > 
> > On Tue, Jan 17, 2023 at 03:35:08AM +0000, Tian, Kevin wrote:
> > > > From: Jason Gunthorpe <jgg@nvidia.com>
> > > > Sent: Saturday, January 7, 2023 12:43 AM
> > > >
> > > > @@ -2676,7 +2676,7 @@ static int copy_context_table(struct
> > intel_iommu
> > > > *iommu,
> > > >  			if (!old_ce)
> > > >  				goto out;
> > > >
> > > > -			new_ce = alloc_pgtable_page(iommu->node);
> > > > +			new_ce = alloc_pgtable_page(iommu->node,
> > > > GFP_KERNEL);
> > >
> > > GFP_ATOMIC
> > 
> > Can't be:
> > 
> > 			old_ce = memremap(old_ce_phys, PAGE_SIZE,
> > 					MEMREMAP_WB);
> > 			if (!old_ce)
> > 				goto out;
> > 
> > 			new_ce = alloc_pgtable_page(iommu->node,
> > GFP_KERNEL);
> > 			if (!new_ce)
> > 
> > memremap() is sleeping.
> > 
> > And the only caller is:
> > 
> > 	ctxt_tbls = kcalloc(ctxt_table_entries, sizeof(void *), GFP_KERNEL);
> > 	if (!ctxt_tbls)
> > 		goto out_unmap;
> > 
> > 	for (bus = 0; bus < 256; bus++) {
> > 		ret = copy_context_table(iommu, &old_rt[bus],
> > 					 ctxt_tbls, bus, ext);
> > 
> 
> Yes, but the patch description says "Push the GFP_ATOMIC to all
> callers." implying it's purely a refactoring w/o changing those
> semantics.

Sure, lets split the patch, it is a good idea

Jason