From: Christoph Hellwig <hch@lst.de>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Stephen Warren <swarren@wwwdotorg.org>,
Christoph Hellwig <hch@lst.de>,
Tariq Toukan <tariqt@mellanox.com>,
xavier.huwei@huawei.com,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
Doug Ledford <dledford@redhat.com>
Subject: Re: [RFC PATCH] net/mlx4: Get rid of page operation after dma_alloc_coherent
Date: Tue, 18 Dec 2018 19:50:12 +0100 [thread overview]
Message-ID: <20181218185012.GB16052@lst.de> (raw)
In-Reply-To: <20181218184308.GD21992@ziepe.ca>
On Tue, Dec 18, 2018 at 11:43:08AM -0700, Jason Gunthorpe wrote:
> So the problem here is that on some arches
>
> sg_set_buf(sg, dma_coherent_buf, size)
> p = sg_virt(sg);
> assert(p == dma_coherent_buf);
dma allocations purely return a virtual address, you must never
call virt_to_page or virt_to_phys on them, which sg_set_buf
will do. On many architectures this will give your the wrong
result as the coherent DMA address is a vmap or ioremap address.
next prev parent reply other threads:[~2018-12-18 18:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-14 23:32 [RFC PATCH] net/mlx4: Get rid of page operation after dma_alloc_coherent Stephen Warren
2018-12-18 13:40 ` Tariq Toukan
2018-12-18 16:32 ` Jason Gunthorpe
2018-12-18 17:08 ` Stephen Warren
2018-12-18 17:12 ` Jason Gunthorpe
2018-12-18 17:45 ` Stephen Warren
2018-12-18 18:43 ` Jason Gunthorpe
2018-12-18 18:50 ` Christoph Hellwig [this message]
2018-12-18 18:51 ` David Miller
2018-12-18 19:04 ` Jason Gunthorpe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181218185012.GB16052@lst.de \
--to=hch@lst.de \
--cc=dledford@redhat.com \
--cc=jgg@ziepe.ca \
--cc=linux-rdma@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=swarren@wwwdotorg.org \
--cc=tariqt@mellanox.com \
--cc=xavier.huwei@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).