linux-kernel - Re: [PATCH v5 01/11] iommu/vt-d: add wrapper functions for page allocations

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Date: Mon, 8 Apr 2024 02:17:30 +0000
From: Linu Cherian <lcherian@...vell.com>
To: Pasha Tatashin <pasha.tatashin@...een.com>
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Subject: Re: [PATCH v5 01/11] iommu/vt-d: add wrapper functions for page
 allocations

Hi Pasha,

> -----Original Message-----
> From: Pasha Tatashin <pasha.tatashin@...een.com>
> Sent: Thursday, April 4, 2024 7:26 PM
> To: Linu Cherian <lcherian@...vell.com>
> Cc: akpm@...ux-foundation.org; alim.akhtar@...sung.com;
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> Subject: [EXTERNAL] Re: [PATCH v5 01/11] iommu/vt-d: add wrapper
> functions for page allocations
> 
> > Few minor nits.
> 
> Hi Linu,
> 
> Thank you for taking a look at this patch, my replies below.
> 
> > > +/*
> > > + * All page allocations that should be reported to as
> > > +"iommu-pagetables" to
> > > + * userspace must use on of the functions below.  This includes
> > > +allocations of
> > > + * page-tables and other per-iommu_domain configuration structures.
> >
> > /s/use on/use one/?
> 
> I will correct in the next version (if there is going to be one).
> 
> > > + *
> > > + * This is necessary for the proper accounting as IOMMU state can
> > > + be rather
> > > + * large, i.e. multiple gigabytes in size.
> > > + */
> > > +
> > > +/**
> > > + * __iommu_alloc_pages - allocate a zeroed page of a given order.
> > > + * @gfp: buddy allocator flags
> >
> > Shall we keep the comments generic here(avoid reference to allocator
> > algo)  ?
> 
> There are no references to allocator algorithm. I specify the zero page
> because this function adds __GFP_ZERO. The order and gfp arguments are
> provided by the caller, therefore, should be mentioned.

Just meant to remove the mention of "buddy allocator" in the above comments if I was not clear.
Ie. "* @gfp:  allocator flags"  instead of "* @gfp: buddy allocator flags" since that is allocator specific.

Thanks
Linu Cherian.