From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Frank Wunderlich <frank-w@public-files.de>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Marek Szyprowski <m.szyprowski@samsung.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: helping with remapping vmem for dma
Date: Wed, 15 Jun 2022 15:17:00 +0200 [thread overview]
Message-ID: <20220615131700.GA18061@lst.de> (raw)
In-Reply-To: <6e58b50c-cd05-a37b-07e1-10ee24fb972f@arm.com>
On Wed, Jun 15, 2022 at 02:15:33PM +0100, Robin Murphy wrote:
> Put simply, if you want to call dma_map_single() on a buffer, then that
> buffer needs to be allocated with kmalloc() (or technically alloc_pages(),
> but then dma_map_page() would make more sense when dealing with entire
> pages.
Yes. It sounds like the memory here comes from the dma coherent
allocator, in which case the code need to use the address returned
by that and not create another mapping.
next prev parent reply other threads:[~2022-06-15 13:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-15 12:11 helping with remapping vmem for dma Frank Wunderlich
2022-06-15 13:15 ` Robin Murphy
2022-06-15 13:17 ` Christoph Hellwig [this message]
2022-06-15 14:46 ` Frank Wunderlich
-- strict thread matches above, loose matches on Subject: below --
2022-06-17 16:17 Frank Wunderlich
2022-06-17 17:22 ` Robin Murphy
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