From: Matthew Wilcox <willy@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Yury Norov <yury.norov@gmail.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Nicholas Piggin <npiggin@gmail.com>,
Ding Tianhong <dingtianhong@huawei.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Alexey Klimov <aklimov@redhat.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] vmap(): don't allow invalid pages
Date: Wed, 26 Jan 2022 02:50:51 +0000 [thread overview]
Message-ID: <YfC3C5MiyKzSX4Sg@casper.infradead.org> (raw)
In-Reply-To: <f85b3cac-29e7-4179-e078-fd859040c294@arm.com>
On Wed, Jan 19, 2022 at 01:28:14PM +0000, Robin Murphy wrote:
> Is it page_to_pfn() guaranteed to work without blowing up if page is invalid
> in the first place? Looking at the CONFIG_SPARSEMEM case I'm not sure that's
> true...
Something that all the ARM people weighing in on this don't understand
is that basically nobody uses SPARSEMEM without SPARSEMEM_VMEMMAP.
So all this complicated code to do page_to_pfn() is never tested.
Real users all do a simple subtraction and so the simple pfn_valid()
works fine.
prev parent reply other threads:[~2022-01-26 2:51 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 23:52 [PATCH] vmap(): don't allow invalid pages Yury Norov
2022-01-19 0:51 ` Matthew Wilcox
2022-01-19 6:17 ` Anshuman Khandual
2022-01-19 17:22 ` Yury Norov
2022-01-20 3:37 ` Anshuman Khandual
2022-01-20 4:27 ` Matthew Wilcox
2022-01-21 2:56 ` Yury Norov
2022-01-19 11:16 ` Mark Rutland
2022-01-19 17:00 ` Yury Norov
2022-01-19 18:06 ` Mark Rutland
2022-01-19 13:28 ` Robin Murphy
2022-01-19 16:27 ` Matthew Wilcox
2022-01-19 17:54 ` Russell King (Oracle)
2022-01-19 18:01 ` Matthew Wilcox
2022-01-19 18:57 ` Russell King (Oracle)
2022-01-19 19:35 ` Matthew Wilcox
2022-01-19 22:38 ` Russell King (Oracle)
2022-01-19 18:43 ` Robin Murphy
2022-01-19 19:12 ` Russell King (Oracle)
2022-01-20 12:22 ` Robin Murphy
2022-01-20 13:03 ` Russell King (Oracle)
2022-01-20 16:37 ` Robin Murphy
2022-01-20 16:54 ` Russell King (Oracle)
2022-01-20 19:04 ` Matthew Wilcox
2022-01-21 5:26 ` Yury Norov
2022-01-26 2:50 ` Matthew Wilcox [this message]
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