From: Christoph Hellwig <hch@infradead.org>
To: Lauri Kasanen <cand@gmx.com>
Cc: Keith Busch <kbusch@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
linux-mips@vger.kernel.org, tsbogend@alpha.franken.de,
axboe@kernel.dk, linux-block@vger.kernel.org
Subject: Re: [PATCH v9] block: Add n64 cart driver
Date: Fri, 22 Jan 2021 18:20:31 +0000 [thread overview]
Message-ID: <20210122182031.GA255271@infradead.org> (raw)
In-Reply-To: <20210122200117.b1b1cda46cefc840595d2b09@gmx.com>
On Fri, Jan 22, 2021 at 08:01:17PM +0200, Lauri Kasanen wrote:
> On Fri, 22 Jan 2021 09:11:20 -0800
> Keith Busch <kbusch@kernel.org> wrote:
> > Each bio_vec segment is physically contiguous.
>
> What's the official way to get that buffer's physical address? I
> couldn't find any driver that does DMA to the bio buffer, to use as an
> example. Maybe used wrong keywords.
In Linux we never DMA to the physical address, but the DMA address.
For a bio with just a single bvec (that is a single contigous segment)
we have the dma_map_bvec helper that is only used by the nvme-pci
driver for special optimizations in the case of a single contigous
segment.
prev parent reply other threads:[~2021-01-22 18:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 9:00 [PATCH v9] block: Add n64 cart driver Lauri Kasanen
2021-01-22 11:17 ` Christoph Hellwig
2021-01-22 13:58 ` Lauri Kasanen
2021-01-22 16:18 ` Christoph Hellwig
2021-01-22 16:23 ` Lauri Kasanen
2021-01-22 16:39 ` Christoph Hellwig
2021-01-22 16:56 ` Lauri Kasanen
2021-01-22 17:08 ` Christoph Hellwig
2021-01-22 17:11 ` Keith Busch
2021-01-22 18:01 ` Lauri Kasanen
2021-01-22 18:20 ` Christoph Hellwig [this message]
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