From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Tomasz Figa <tfiga@chromium.org>,
Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
Ricardo Ribalda <ribalda@chromium.org>,
Christoph Hellwig <hch@lst.de>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv4 8/8] videobuf2: handle non-contiguous DMA allocations
Date: Mon, 23 Aug 2021 19:29:46 +0900 [thread overview]
Message-ID: <YSN4ms1VoJO2CWNp@google.com> (raw)
In-Reply-To: <fd1e8bbe-4cbe-9586-7c8f-0896af043d4a@xs4all.nl>
On (21/08/03 12:15), Hans Verkuil wrote:
> > static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
> > {
> > struct vb2_dc_buf *buf = buf_priv;
> > - struct dma_buf_map map;
> > - int ret;
> >
> > - if (!buf->vaddr && buf->db_attach) {
> > - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
> > - buf->vaddr = ret ? NULL : map.vaddr;
> > + 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;
> > }
>
> This function really needs a bunch of comments.
>
> What I want to see here specifically is under which circumstances this function
> can return NULL.
>
> - dma_buf_vmap returns an error
> - for non-coherent memory dma_vmap_noncontiguous returns an error
> - coherent memory with DMA_ATTR_NO_KERNEL_MAPPING set.
Done.
prev parent reply other threads:[~2021-08-23 10:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-27 7:05 [PATCHv4 0/8] videobuf2: support new noncontiguous DMA API Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 1/8] videobuf2: rework vb2_mem_ops API Sergey Senozhatsky
2021-08-03 8:08 ` Hans Verkuil
2021-08-17 10:41 ` Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 2/8] videobuf2: inverse buffer cache_hints flags Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 3/8] videobuf2: split buffer cache_hints initialisation Sergey Senozhatsky
2021-08-03 8:10 ` Hans Verkuil
2021-08-17 10:41 ` Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 4/8] videobuf2: move cache_hints handling to allocators Sergey Senozhatsky
2021-08-03 8:11 ` Hans Verkuil
2021-08-17 10:42 ` Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-08-03 8:12 ` Hans Verkuil
2021-08-17 10:42 ` Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 6/8] videobuf2: add queue memory coherency parameter Sergey Senozhatsky
2021-08-03 8:29 ` Hans Verkuil
2021-08-17 10:43 ` Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-08-03 8:31 ` Hans Verkuil
2021-08-17 10:43 ` Sergey Senozhatsky
2021-07-27 7:05 ` [PATCHv4 8/8] videobuf2: handle non-contiguous DMA allocations Sergey Senozhatsky
2021-08-03 8:33 ` Hans Verkuil
2021-08-03 8:39 ` Hans Verkuil
2021-08-23 10:28 ` Sergey Senozhatsky
2021-08-23 10:27 ` Sergey Senozhatsky
2021-08-03 10:15 ` Hans Verkuil
2021-08-17 11:56 ` Sergey Senozhatsky
2021-08-18 9:20 ` Tomasz Figa
2021-08-23 10:29 ` Sergey Senozhatsky [this message]
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