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.stanisl...@samsung.com>
Acked-by: Hans Verkuil <hans.verk...@cisco.com>
---
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 */
+ get_device(dev);
+
buf->dev = dev;
buf->size = size;
--
1.7.9.5
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