Hi Tomasz,
Thanks for the patch.
On Wednesday 10 October 2012 16:46:40 Tomasz Stanislawski wrote:
This patch adds taking reference to the device for MMAP buffers.
Such buffers, may be exported using DMABUF mechanism. If the driver that created a queue is unloaded then the queue is released, the device might be released too. However, buffers cannot be released if they are referenced by DMABUF descriptor(s). The device pointer kept in a buffer must be valid for the whole buffer's lifetime. Therefore MMAP buffers should take a reference to the device to avoid risk of dangling pointers.
Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Acked-by: Hans Verkuil hans.verkuil@cisco.com
Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
But two small comments below.
drivers/media/v4l2-core/videobuf2-dma-contig.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b138b5c..2d661fd 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv) kfree(buf->sgt_base); } dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
- put_device(buf->dev); kfree(buf);
}
@@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size) return ERR_PTR(-ENOMEM); }
- /* prevent the device from release while the buffer is exported */
s/prevent/Prevent/ ?
- get_device(dev);
- buf->dev = dev;
What about just
buf->dev = get_device(dev);
buf->size = size;