From: "Michal Nazarewicz" <mina86@mina86.com>
To: Dan Smith <danms@us.ibm.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Ensure that walk_page_range()'s start and end are page-aligned
Date: Fri, 10 Feb 2012 21:13:07 +0100 [thread overview]
Message-ID: <op.v9hbr5xx3l0zgt@mpn-glaptop> (raw)
In-Reply-To: <874nuy31hw.fsf@caffeine.danplanet.com>
On Fri, 10 Feb 2012 20:57:31 +0100, Dan Smith <danms@us.ibm.com> wrote:
> MN> Commit message says about walk_pte_range() but commit changes
> MN> walk_page_range().
>
> Yep, the issue occurs in walk_pte_range().
OK, it wasn't immediately obvious for me that while loop in walk_page_range()
will actually recover if arguments are not aligned (since pgd_addr_end() caps
returned value).
> The goal was to ensure that
> the external interface to it (which is walk_page_range()) does the check
> and avoids doing the walk entirely. I think the expectation is that
> walk_page_range() is used on aligned addresses. If we put the check in
> walk_pte_range() then only walks with a pte_entry handler would fail on
> unaligned addresses, which is potentially confusing.
>
> MN> So why not change the condition to addr < end?
>
> That would work, of course, but seems sloppier and less precise. The
> existing code was clearly written expecting to walk aligned addresses.
Fair enough.
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
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next prev parent reply other threads:[~2012-02-10 20:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-10 19:39 Dan Smith
2012-02-10 19:45 ` Michal Nazarewicz
2012-02-10 19:57 ` Dan Smith
2012-02-10 20:13 ` Michal Nazarewicz [this message]
2012-02-13 10:12 ` David Rientjes
2012-02-13 14:52 ` Dan Smith
2012-02-13 21:55 ` David Rientjes
2012-02-14 14:59 ` Dan Smith
2012-02-14 21:04 ` David Rientjes
2012-02-15 14:39 ` Dan Smith
2012-02-24 19:19 ` Dan Smith
2012-02-24 20:55 ` Andrew Morton
2012-02-24 21:03 ` Dan Smith
-- strict thread matches above, loose matches on Subject: below --
2012-02-10 15:53 Dan Smith
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