| Message ID | 20200302041213.27662-11-senozhatsky@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Implement V4L2_BUF_FLAG_NO_CACHE_* flags | expand |
On 02/03/2020 05:12, Sergey Senozhatsky wrote: > Provide begin_cpu_access() and end_cpu_access() dma_buf_ops > callbacks for cache synchronisation on exported buffers. > > V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. > dma-sg allocates memory using the page allocator directly, so > there is no memory consistency guarantee. > > Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> > --- > .../media/common/videobuf2/videobuf2-dma-sg.c | 28 +++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c > index 6db60e9d5183..ddc67c9aaedb 100644 > --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c > +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c > @@ -120,6 +120,12 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs, > buf->num_pages = size >> PAGE_SHIFT; > buf->dma_sgt = &buf->sg_table; > > + /* > + * NOTE: dma-sg allocates memory using the page allocator directly, so > + * there is no memory consistency guarantee, hence dma-sg ignores DMA > + * attributes passed from the upper layer. That means that > + * V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. > + */ > buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), > GFP_KERNEL | __GFP_ZERO); > if (!buf->pages) > @@ -470,6 +476,26 @@ static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) > vb2_dma_sg_put(dbuf->priv); > } > > +static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, > + enum dma_data_direction direction) I suggest you use this style to avoid checkpatch warnings: static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, enum dma_data_direction direction) > +{ > + struct vb2_dma_sg_buf *buf = dbuf->priv; > + struct sg_table *sgt = buf->dma_sgt; > + > + dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); > + return 0; > +} > + > +static int vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, > + enum dma_data_direction direction) Ditto. Regards, Hans > +{ > + struct vb2_dma_sg_buf *buf = dbuf->priv; > + struct sg_table *sgt = buf->dma_sgt; > + > + dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); > + return 0; > +} > + > static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) > { > struct vb2_dma_sg_buf *buf = dbuf->priv; > @@ -488,6 +514,8 @@ static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { > .detach = vb2_dma_sg_dmabuf_ops_detach, > .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, > .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, > + .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access, > + .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access, > .vmap = vb2_dma_sg_dmabuf_ops_vmap, > .mmap = vb2_dma_sg_dmabuf_ops_mmap, > .release = vb2_dma_sg_dmabuf_ops_release, >
On (20/03/06 15:04), Hans Verkuil wrote: [..] > > + /* > > + * NOTE: dma-sg allocates memory using the page allocator directly, so > > + * there is no memory consistency guarantee, hence dma-sg ignores DMA > > + * attributes passed from the upper layer. That means that > > + * V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. > > + */ > > buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), > > GFP_KERNEL | __GFP_ZERO); > > if (!buf->pages) > > @@ -470,6 +476,26 @@ static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) > > vb2_dma_sg_put(dbuf->priv); > > } > > > > +static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, > > + enum dma_data_direction direction) > > I suggest you use this style to avoid checkpatch warnings: > > static int > vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, > enum dma_data_direction direction) OK, will do. Just for information, my checkpatch doesn't warn me: $ ./scripts/checkpatch.pl outgoing/0010-videobuf2-add-begin-end-cpu_access-callbacks-to-dma-.patch total: 0 errors, 0 warnings, 46 lines checked outgoing/0010-videobuf2-add-begin-end-cpu_access-callbacks-to-dma-.patch has no obvious style problems and is ready for submission. -ss
On 07/03/2020 06:26, Sergey Senozhatsky wrote: > On (20/03/06 15:04), Hans Verkuil wrote: > [..] >>> + /* >>> + * NOTE: dma-sg allocates memory using the page allocator directly, so >>> + * there is no memory consistency guarantee, hence dma-sg ignores DMA >>> + * attributes passed from the upper layer. That means that >>> + * V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. >>> + */ >>> buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), >>> GFP_KERNEL | __GFP_ZERO); >>> if (!buf->pages) >>> @@ -470,6 +476,26 @@ static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) >>> vb2_dma_sg_put(dbuf->priv); >>> } >>> >>> +static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, >>> + enum dma_data_direction direction) >> >> I suggest you use this style to avoid checkpatch warnings: >> >> static int >> vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, >> enum dma_data_direction direction) > > OK, will do. > > Just for information, my checkpatch doesn't warn me: > > $ ./scripts/checkpatch.pl outgoing/0010-videobuf2-add-begin-end-cpu_access-callbacks-to-dma-.patch We use the --strict option to checkpatch. Regards, Hans > total: 0 errors, 0 warnings, 46 lines checked > > outgoing/0010-videobuf2-add-begin-end-cpu_access-callbacks-to-dma-.patch has no obvious style problems and is ready for submission. > > -ss >
On (20/03/07 10:32), Hans Verkuil wrote: > >>> +static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, > >>> + enum dma_data_direction direction) > >> > >> I suggest you use this style to avoid checkpatch warnings: > >> > >> static int > >> vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, > >> enum dma_data_direction direction) > > > > OK, will do. > > > > Just for information, my checkpatch doesn't warn me: > > > > $ ./scripts/checkpatch.pl outgoing/0010-videobuf2-add-begin-end-cpu_access-callbacks-to-dma-.patch > > We use the --strict option to checkpatch. Got it. -ss
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c index 6db60e9d5183..ddc67c9aaedb 100644 --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c @@ -120,6 +120,12 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs, buf->num_pages = size >> PAGE_SHIFT; buf->dma_sgt = &buf->sg_table; + /* + * NOTE: dma-sg allocates memory using the page allocator directly, so + * there is no memory consistency guarantee, hence dma-sg ignores DMA + * attributes passed from the upper layer. That means that + * V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. + */ buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *), GFP_KERNEL | __GFP_ZERO); if (!buf->pages) @@ -470,6 +476,26 @@ static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) vb2_dma_sg_put(dbuf->priv); } +static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, + enum dma_data_direction direction) +{ + struct vb2_dma_sg_buf *buf = dbuf->priv; + struct sg_table *sgt = buf->dma_sgt; + + dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); + return 0; +} + +static int vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, + enum dma_data_direction direction) +{ + struct vb2_dma_sg_buf *buf = dbuf->priv; + struct sg_table *sgt = buf->dma_sgt; + + dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); + return 0; +} + static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) { struct vb2_dma_sg_buf *buf = dbuf->priv; @@ -488,6 +514,8 @@ static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { .detach = vb2_dma_sg_dmabuf_ops_detach, .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, + .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access, + .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access, .vmap = vb2_dma_sg_dmabuf_ops_vmap, .mmap = vb2_dma_sg_dmabuf_ops_mmap, .release = vb2_dma_sg_dmabuf_ops_release,
Provide begin_cpu_access() and end_cpu_access() dma_buf_ops callbacks for cache synchronisation on exported buffers. V4L2_FLAG_MEMORY_NON_CONSISTENT has no effect on dma-sg buffers. dma-sg allocates memory using the page allocator directly, so there is no memory consistency guarantee. Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> --- .../media/common/videobuf2/videobuf2-dma-sg.c | 28 +++++++++++++++++++ 1 file changed, 28 insertions(+)