From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Tomasz Figa <tfiga@chromium.org>,
Ricardo Ribalda <ribalda@chromium.org>,
Christoph Hellwig <hch@lst.de>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv2 8/8] videobuf2: handle non-contiguous DMA allocations
Date: Fri, 25 Jun 2021 12:10:30 +0900 [thread overview]
Message-ID: <YNVJJhP69KPJ+DHv@google.com> (raw)
In-Reply-To: <YMsAIVs7G2hUDR2F@google.com>
Hi Hans,
On (21/06/17 16:56), Sergey Senozhatsky wrote:
[..]
> static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> {
> struct vb2_dc_buf *buf = buf_priv;
>
> if (buf->vaddr)
> return buf->vaddr;
>
> if (buf->db_attach) {
> struct dma_buf_map map;
>
> if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
> buf->vaddr = map.vaddr;
>
> return buf->vaddr;
> }
>
> if (!buf->coherent_mem)
> buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
> buf->dma_sgt);
> return buf->vaddr;
> }
>
> And in vb2_dc_alloc functions set vaddr for !DMA_ATTR_NO_KERNEL_MAPPING
> in both coherent and non-coherent. So that we probably can have less
> branches when ->vaddr is NULL for one type of allocations, and is not
> NULL for another.
>
> static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
> {
> struct vb2_queue *q = buf->vb->vb2_queue;
>
> buf->cookie = dma_alloc_attrs(buf->dev,
> buf->size,
> &buf->dma_addr,
> GFP_KERNEL | q->gfp_flags,
> buf->attrs);
> if (!buf->cookie)
> return -ENOMEM;
>
> if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
> return 0;
>
> buf->vaddr = buf->cookie;
> return 0;
> }
>
> static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
> {
> struct vb2_queue *q = buf->vb->vb2_queue;
>
> buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
> buf->size,
> buf->dma_dir,
> GFP_KERNEL | q->gfp_flags,
> buf->attrs);
> if (!buf->dma_sgt)
> return -ENOMEM;
>
> if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
> return 0;
>
> buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size, buf->dma_sgt);
> if (!buf->vaddr) {
> dma_free_noncontiguous(buf->dev, buf->size,
> buf->dma_sgt, buf->dma_addr);
> return -ENOMEM;
> }
> return 0;
> }
I guess this should address the case when
"after allocating the buffer, the buffer is exported as a dma_buf and
another device calls dma_buf_ops vb2_dc_dmabuf_ops_vmap, which in turn
calls dma_buf_map_set_vaddr(map, buf->vaddr); with a NULL buf->vaddr"
Because ->vaddr will not be NULL now after allocation for both coherent
and non-coherent buffers (modulo DMA_ATTR_NO_KERNEL_MAPPING requests).
What do you think?
next prev parent reply other threads:[~2021-06-25 3:10 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 13:13 [PATCHv2 0/8] videobuf2: support new noncontiguous DMA API Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 1/8] videobuf2: rework vb2_mem_ops API Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 2/8] videobuf2: inverse buffer cache_hints flags Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 3/8] videobuf2: split buffer cache_hints initialisation Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 4/8] videobuf2: move cache_hints handling to allocators Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 6/8] videobuf2: add queue memory coherency parameter Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-05-01 3:48 ` Sergey Senozhatsky
2021-06-03 11:32 ` Hans Verkuil
2021-06-17 1:46 ` Sergey Senozhatsky
2021-04-27 13:13 ` [PATCHv2 8/8] videobuf2: handle non-contiguous DMA allocations Sergey Senozhatsky
2021-04-28 6:14 ` Christoph Hellwig
2021-06-03 11:59 ` Hans Verkuil
2021-06-17 7:56 ` Sergey Senozhatsky
2021-06-17 8:01 ` Christoph Hellwig
2021-06-17 8:30 ` Tomasz Figa
2021-06-17 8:52 ` Christoph Hellwig
2021-06-17 9:40 ` Tomasz Figa
2021-06-17 10:06 ` Christoph Hellwig
2021-06-18 3:21 ` Tomasz Figa
2021-06-18 4:25 ` Christoph Hellwig
2021-06-18 4:44 ` Tomasz Figa
2021-06-22 7:33 ` Christoph Hellwig
2021-07-07 12:42 ` Tomasz Figa
2021-06-25 3:10 ` Sergey Senozhatsky [this message]
2021-07-07 12:48 ` Tomasz Figa
2021-07-07 13:29 ` Sergey Senozhatsky
2021-07-07 14:10 ` Tomasz Figa
2021-07-09 7:20 ` Sergey Senozhatsky
2021-06-17 7:56 ` Sergey Senozhatsky
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