intel-gfx.lists.freedesktop.org archive mirror
 help / color / mirror / Atom feed
From: "Christian König" <christian.koenig@amd.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: David1.Zhou@amd.com, intel-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
	jgg@ziepe.ca, linux-media@vger.kernel.org
Subject: Re: [Intel-gfx] [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function
Date: Thu, 12 Mar 2020 12:02:09 +0100	[thread overview]
Message-ID: <211ea421-3621-b380-cada-c2432da45172@amd.com> (raw)
In-Reply-To: <20200312104729.GA26031@infradead.org>

Am 12.03.20 um 11:47 schrieb Christoph Hellwig:
> On Thu, Mar 12, 2020 at 11:31:35AM +0100, Christian König wrote:
> [SNIP]
>> I mean we could come up with a new structure for this, but to me that just
>> looks like reinventing the wheel. Especially since drivers need to be able
>> to handle both I/O to system memory and I/O to PCIe BARs.
> The structure for holding the struct page side of the scatterlist is
> called struct bio_vec, so far mostly used by the block and networking
> code.

Yeah, I'm aware of this.

> The structure for holding dma addresses doesn't really exist
> in a generic form, but would be an array of these structures:
>
> struct dma_sg {
> 	dma_addr_t	addr;
> 	u32		len;
> };

So the whole idea is to nuke scatterlist/sg_table in the long term and 
switch over to using bio_vec as input and dma_sg as output for a DMA 
mapping operation.

Is that correct? If yes I could live with that, but it makes my patchset 
much more complicated.

> Keeping them separate is important as most IOMMU drivers will return
> less entries than you can feed them.  E.g. if your input boundaries
> are 4k aligned you will usually just get a single IOVA entry back.
> I will soon also have a dma mapping interface that will take advantage
> of that fact.

Yeah, I noticed as well that this is not really well handled.

Thanks for the feedback,
Christian.
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

  reply	other threads:[~2020-03-12 11:02 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 13:51 [Intel-gfx] P2P for DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function Christian König
2020-03-11 15:28   ` Christoph Hellwig
2020-03-12 10:14     ` Christian König
2020-03-12 10:19       ` Christoph Hellwig
2020-03-12 10:31         ` Christian König
2020-03-12 10:47           ` Christoph Hellwig
2020-03-12 11:02             ` Christian König [this message]
     [not found]             ` <20200312141928.GK31668@ziepe.ca>
2020-03-12 15:39               ` Christian König
2020-03-12 16:13               ` Logan Gunthorpe
2020-03-13 11:21               ` Christoph Hellwig
2020-03-13 13:33                 ` Christian König
     [not found]                 ` <20200313121742.GZ31668@ziepe.ca>
2020-03-16  8:56                   ` Christoph Hellwig
2020-03-16  9:41                     ` Christian König
2020-03-16  9:52                       ` Christoph Hellwig
2020-03-11 13:51 ` [Intel-gfx] [PATCH 2/6] dma-buf: add peer2peer flag Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 3/6] drm/amdgpu: note that we can handle peer2peer DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 4/6] drm/amdgpu: add checks if DMA-buf P2P is supported Christian König
     [not found]   ` <20200311140415.GB31668@ziepe.ca>
2020-03-11 14:33     ` Christian König
     [not found]       ` <20200311143835.GD31668@ziepe.ca>
2020-03-11 14:43         ` Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 5/6] drm/amdgpu: add support for exporting VRAM using DMA-buf v2 Christian König
2020-03-11 15:08   ` Alex Deucher
2020-03-11 13:51 ` [Intel-gfx] [PATCH 6/6] drm/amdgpu: improve amdgpu_gem_info debugfs file Christian König
2020-03-11 18:09 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/6] lib/scatterlist: add sg_set_dma_addr() function Patchwork
2020-03-11 18:34 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork

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=211ea421-3621-b380-cada-c2432da45172@amd.com \
    --to=christian.koenig@amd.com \
    --cc=David1.Zhou@amd.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=hch@infradead.org \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=jgg@ziepe.ca \
    --cc=linaro-mm-sig@lists.linaro.org \
    --cc=linux-media@vger.kernel.org \
    --subject='Re: [Intel-gfx] [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function' \
    /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

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).