linux-kernel - Re: [PATCH v3 02/17] arm64, hibernate: use get_safe

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Message-ID: <dc6506a0-9b66-f633-8319-9c8a9dc93d4f@arm.com>
Date:   Fri, 6 Sep 2019 16:17:25 +0100
From:   James Morse <james.morse@....com>
To:     Pavel Tatashin <pasha.tatashin@...een.com>
Cc:     jmorris@...ei.org, sashal@...nel.org, ebiederm@...ssion.com,
        kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
        corbet@....net, catalin.marinas@....com, will@...nel.org,
        linux-arm-kernel@...ts.infradead.org, marc.zyngier@....com,
        vladimir.murzin@....com, matthias.bgg@...il.com,
        bhsharma@...hat.com, linux-mm@...ck.org, mark.rutland@....com
Subject: Re: [PATCH v3 02/17] arm64, hibernate: use get_safe_page directly

Hi Pavel,

Nit: The pattern for the subject prefix should be "arm64: hibernate:"..
Its usually possible to spot the pattern from "git log --oneline $file".

On 21/08/2019 19:31, Pavel Tatashin wrote:
> create_safe_exec_page is a local function that uses the
> get_safe_page() to allocate page table and pages and one pages
> that is getting mapped.

I can't parse this.

create_safe_exec_page() uses hibernate's allocator to create a set of page table to map a
single page that will contain the relocation code.

> Remove the allocator related arguments, and use get_safe_page
> directly, as it is done in other local functions in this
> file.
... because kexec can't use this as it doesn't have a working allocator.
Removing this function pointer makes it easier to refactor the code later.

(this thing is only a function pointer so kexec could use it too ... It looks like you're
creating extra work. Patch 7 moves these new calls out to a new file... presumably so
another patch can remove them again)

As stand-alone cleanup the patch looks fine, but you probably don't need to do this.

Thanks,

James