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Subject: Re: [PATCH v3 0/3] Encapsulate PTE contents from non-arch code
From:   Muchun Song <muchun.song@linux.dev>
In-Reply-To: <20230612151545.3317766-1-ryan.roberts@arm.com>
Date:   Tue, 13 Jun 2023 10:16:26 +0800
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To:     Ryan Roberts <ryan.roberts@arm.com>
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> On Jun 12, 2023, at 23:15, Ryan Roberts <ryan.roberts@arm.com> wrote:
>=20
> Hi All,
>=20
> (Including wider audience this time since changes touch a fair few =
subsystems)
>=20
> This is the second half of v3 of a series to improve the encapsulation =
of pte
> entries by disallowing non-arch code from directly dereferencing pte_t =
pointers.
> Based on earlier feedback, I split the series in 2; the first part, =
fixes for
> existing bugs, was already posted at [3] and merged into mm-stable. =
This second
> part contains the conversion from direct dereferences to instead use
> ptep_get()/ptep_get_lockless().
>=20
> See the v1 cover letter at [1] for rationale for this work.
>=20
> Based on feedback at v2, I've removed the new ptep_deref() helper I =
originally
> added, and am now using the existing ptep_get() and =
ptep_get_lockless() helpers.

When I first saw the name of ptep_get()/ptep_get_lockless(), I thought
the pte seems like to be protected by the refcount mechanism (Why I have
this though? Because Qi Zheng has proposed a approach to free pte page =
tables
by using the refcount mechanism [1]). And your proposed name of =
ptep_deref()
is intuitive for me, so I have another thought, should we rename =
ptep_get()
to ptep_deref()? Just a thought from me, I'd like to hear if others =
object.

Thanks.

[1] =
https://lore.kernel.org/lkml/20211110105428.32458-7-zhengqi.arch@bytedance=
.com/=