linux-kernel - Re: [PATCH v3 07/13] mm: introduce io_remap_pfn_range

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Message-ID: <c8eed40b-e0d9-4251-8cd8-6219890d6935@lucifer.local>
Date: Wed, 17 Sep 2025 12:15:12 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: Pedro Falcato <pfalcato@...e.de>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
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Subject: Re: [PATCH v3 07/13] mm: introduce io_remap_pfn_range_[prepare,
 complete]()

On Wed, Sep 17, 2025 at 12:12:17PM +0100, Pedro Falcato wrote:
> On Tue, Sep 16, 2025 at 03:11:53PM +0100, Lorenzo Stoakes wrote:
> > We introduce the io_remap*() equivalents of remap_pfn_range_prepare() and
> > remap_pfn_range_complete() to allow for I/O remapping via mmap_prepare.
> >
> > We have to make some architecture-specific changes for those architectures
> > which define customised handlers.
> >
> > It doesn't really make sense to make this internal-only as arches specify
> > their version of these functions so we declare these in mm.h.
>
> Similar question to the remap_pfn_range patch.

There's arch-specific implementations, which in turn invoke the new
prepare/complete helpers.

(This answers your query here and on the remap_pfn_prepare/complete patch).

With the abstraction of the get pfn function suggested by Jason it may be
possible to move these over and just utilise that in internal.h/util.c.

I will look into that.

> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
>
> Looks ok, but again, i'm no expert on this.
>
> Acked-by: Pedro Falcato <pfalcato@...e.de>

Thanks!

>
> --
> Pedro

Cheers, Lorenzo