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From: Christoph Hellwig <hch@lst.de>
To: Mike Rapoport <rppt@kernel.org>
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>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [BUG 5.14] arm64/mm: dma memory mapping fails (in some cases)
Date: Sat, 18 Sep 2021 07:18:43 +0200	[thread overview]
Message-ID: <20210918051843.GA16104@lst.de> (raw)
In-Reply-To: <YUUHJ5EI+6Mop4Wu@kernel.org>

On Sat, Sep 18, 2021 at 12:22:47AM +0300, Mike Rapoport wrote:
> I did some digging and it seems that the most "generic" way to check if a
> page is in RAM is page_is_ram(). It's not 100% bullet proof as it'll give
> false negatives for architectures that do not register "System RAM", but
> those are not using dma_map_resource() anyway and, apparently, never would.

The downside of page_is_ram is that it looks really expensiv for
something done at dma mapping time.


  reply	other threads:[~2021-09-18  5:18 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 [this message]
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
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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