From: "Christian König" <christian.koenig@amd.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: David1.Zhou@amd.com, jgg@ziepe.ca, daniel@ffwll.ch,
dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org
Subject: Re: [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.
WARNING: multiple messages have this Message-ID (diff)
From: "Christian König" <christian.koenig@amd.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: 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: [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.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2020-03-12 11:02 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 13:51 P2P for DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 13:51 ` [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 15:28 ` Christoph Hellwig
2020-03-11 15:28 ` [Intel-gfx] " Christoph Hellwig
2020-03-12 10:14 ` Christian König
2020-03-12 10:14 ` [Intel-gfx] " Christian König
2020-03-12 10:14 ` Christian König
2020-03-12 10:19 ` Christoph Hellwig
2020-03-12 10:19 ` [Intel-gfx] " Christoph Hellwig
2020-03-12 10:31 ` Christian König
2020-03-12 10:31 ` [Intel-gfx] " Christian König
2020-03-12 10:31 ` Christian König
2020-03-12 10:47 ` Christoph Hellwig
2020-03-12 10:47 ` [Intel-gfx] " Christoph Hellwig
2020-03-12 11:02 ` Christian König [this message]
2020-03-12 11:02 ` Christian König
2020-03-12 11:02 ` Christian König
2020-03-12 14:19 ` Jason Gunthorpe
2020-03-12 14:19 ` Jason Gunthorpe
2020-03-12 15:39 ` Christian König
2020-03-12 15:39 ` [Intel-gfx] " Christian König
2020-03-12 15:39 ` Christian König
2020-03-12 16:19 ` Jason Gunthorpe
2020-03-12 16:19 ` Jason Gunthorpe
2020-03-12 16:13 ` Logan Gunthorpe
2020-03-12 16:13 ` [Intel-gfx] " Logan Gunthorpe
2020-03-12 16:13 ` Logan Gunthorpe
2020-03-13 11:21 ` Christoph Hellwig
2020-03-13 11:21 ` [Intel-gfx] " Christoph Hellwig
2020-03-13 12:17 ` Jason Gunthorpe
2020-03-13 12:17 ` Jason Gunthorpe
2020-03-16 8:56 ` Christoph Hellwig
2020-03-16 8:56 ` [Intel-gfx] " Christoph Hellwig
2020-03-16 9:41 ` Christian König
2020-03-16 9:41 ` [Intel-gfx] " Christian König
2020-03-16 9:41 ` Christian König
2020-03-16 9:52 ` Christoph Hellwig
2020-03-16 9:52 ` [Intel-gfx] " Christoph Hellwig
2020-03-16 12:37 ` Jason Gunthorpe
2020-03-16 12:37 ` Jason Gunthorpe
2020-03-13 13:33 ` Christian König
2020-03-13 13:33 ` [Intel-gfx] " Christian König
2020-03-13 13:33 ` Christian König
2020-03-11 13:51 ` [PATCH 2/6] dma-buf: add peer2peer flag Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 13:51 ` [PATCH 3/6] drm/amdgpu: note that we can handle peer2peer DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 13:51 ` [PATCH 4/6] drm/amdgpu: add checks if DMA-buf P2P is supported Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 14:04 ` Jason Gunthorpe
2020-03-11 14:04 ` Jason Gunthorpe
2020-03-11 14:33 ` Christian König
2020-03-11 14:33 ` [Intel-gfx] " Christian König
2020-03-11 14:33 ` Christian König
2020-03-11 14:38 ` Jason Gunthorpe
2020-03-11 14:38 ` Jason Gunthorpe
2020-03-11 14:43 ` Christian König
2020-03-11 14:43 ` [Intel-gfx] " Christian König
2020-03-11 14:43 ` Christian König
2020-03-11 14:48 ` Jason Gunthorpe
2020-03-11 14:48 ` Jason Gunthorpe
2020-03-11 13:51 ` [PATCH 5/6] drm/amdgpu: add support for exporting VRAM using DMA-buf v2 Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` Christian König
2020-03-11 14:33 ` Jason Gunthorpe
2020-03-11 14:33 ` Jason Gunthorpe
2020-03-11 14:39 ` Jason Gunthorpe
2020-03-11 14:39 ` Jason Gunthorpe
2020-03-11 15:08 ` Alex Deucher
2020-03-11 15:08 ` [Intel-gfx] " Alex Deucher
2020-03-11 15:08 ` Alex Deucher
2020-03-11 13:51 ` [PATCH 6/6] drm/amdgpu: improve amdgpu_gem_info debugfs file Christian König
2020-03-11 13:51 ` [Intel-gfx] " Christian König
2020-03-11 13:51 ` 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
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