Hi Tomasz, On Friday 12 October 2012 08:28:23 Tomasz Stanislawski wrote: > On 10/11/2012 11:49 PM, Laurent Pinchart wrote: > > 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@xxxxxxxxxxx> > >> Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > > > > Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > > > 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/ ? > > s/release/being released/ ? Oops. Of course :-) > >> + get_device(dev); > >> + > >> buf->dev = dev; > > > > What about just > > > > buf->dev = get_device(dev); > > Right, sorry I missed that from your previous review :). -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
