From: Mike Rapoport <rppt@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
David Hildenbrand <david@redhat.com>,
Robin Murphy <robin.murphy@arm.com>,
Alex Bee <knaerzche@gmail.com>, Will Deacon <will@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [BUG 5.14] arm64/mm: dma memory mapping fails (in some cases)
Date: Wed, 22 Sep 2021 10:22:32 +0300 [thread overview]
Message-ID: <YUrZuKSaDnJ+rO0k@kernel.org> (raw)
In-Reply-To: <20210921153805.GA29952@lst.de>
On Tue, Sep 21, 2021 at 05:38:05PM +0200, Christoph Hellwig wrote:
> On Tue, Sep 21, 2021 at 12:34:10PM +0300, Mike Rapoport wrote:
> > > It doesn't create any new mappings. The only real issue is that it
> > > does the wrong thing for RAM in a way that might not be noticed on
> > > simple (x86/PC) platforms.
> >
> > But if the mapping request was rejected by devm_ioremap_resource() because
> > of an attempt to map RAM, why we would get to dma_map_resource() at all?
>
> dma_map_resource takes a phys_addr_t that could come from anywhere.
Right, but it's not different from, say, dma_map_page_attrs() that can get a
struct page from anywhere and there is no actual memory for that struct
page at all. Do you suggest add a check that that struct page is backed by
memory in dma_map_page_attrs() as well?
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2021-09-22 7:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 13:40 [BUG 5.14] arm64/mm: dma memory mapping fails (in some cases) Alex Bee
2021-08-24 17:37 ` Catalin Marinas
2021-08-24 18:06 ` Robin Murphy
2021-08-24 18:28 ` Mike Rapoport
2021-08-24 18:46 ` Robin Murphy
2021-08-24 18:59 ` David Hildenbrand
2021-08-25 10:20 ` Catalin Marinas
2021-08-25 10:28 ` Will Deacon
2021-08-25 10:32 ` Will Deacon
2021-08-25 10:33 ` Robin Murphy
2021-08-25 10:38 ` David Hildenbrand
2021-08-25 10:54 ` Mike Rapoport
2021-08-25 10:55 ` Catalin Marinas
2021-08-25 11:12 ` David Hildenbrand
2021-08-25 17:15 ` Catalin Marinas
2021-08-25 10:58 ` Robin Murphy
2021-08-25 11:21 ` David Hildenbrand
2021-08-25 10:52 ` Mike Rapoport
2021-09-17 21:22 ` Mike Rapoport
2021-09-18 5:18 ` Christoph Hellwig
2021-09-18 8:37 ` Mike Rapoport
2021-09-18 11:39 ` Mike Rapoport
2021-09-20 10:57 ` Catalin Marinas
2021-09-21 8:20 ` Christoph Hellwig
2021-09-21 9:34 ` Mike Rapoport
2021-09-21 15:38 ` Christoph Hellwig
2021-09-22 7:22 ` Mike Rapoport [this message]
2021-09-20 11:13 ` David Hildenbrand
2021-08-24 20:14 ` Alex Bee
2021-08-25 4:39 ` Mike Rapoport
2021-08-25 10:00 ` Alex Bee
2021-08-24 20:07 ` Alex Bee
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