[media] v4l: vb2-dma-contig: remove reference of alloc_ctx from a buffer (72f86bff) · Commits · 戴 / test

This patch removes a reference to alloc_ctx from an instance of a DMA contiguous buffer. It helps to avoid a risk of a dangling pointer if the context is released while the buffer is still valid. Moreover it removes one dereference step while accessing a device structure. Signed-off-by:

Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by:

Kyungmin Park <kyungmin.park@samsung.com> Acked-by:

Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by:

Hans Verkuil <hans.verkuil@cisco.com> Tested-by:

Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by:

Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/v4l2-core/videobuf2-dma-contig.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -23,7 +23,7 @@ struct vb2_dc_conf {
		};

		struct vb2_dc_buf {
		struct vb2_dc_conf *conf;
		struct device *dev;
		void *vaddr;
		dma_addr_t dma_addr;
		unsigned long size;
		@@ -37,22 +37,21 @@ static void vb2_dc_put(void *buf_priv);
		static void vb2_dc_alloc(void alloc_ctx, unsigned long size)
		{
		struct vb2_dc_conf *conf = alloc_ctx;
		struct device *dev = conf->dev;
		struct vb2_dc_buf *buf;

		buf = kzalloc(sizeof *buf, GFP_KERNEL);
		if (!buf)
		return ERR_PTR(-ENOMEM);

		buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->dma_addr,
		GFP_KERNEL);
		buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
		if (!buf->vaddr) {
		dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n",
		size);
		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
		kfree(buf);
		return ERR_PTR(-ENOMEM);
		}

		buf->conf = conf;
		buf->dev = dev;
		buf->size = size;

		buf->handler.refcount = &buf->refcount;
		@@ -69,7 +68,7 @@ static void vb2_dc_put(void *buf_priv)
		struct vb2_dc_buf *buf = buf_priv;

		if (atomic_dec_and_test(&buf->refcount)) {
		dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr,
		dma_free_coherent(buf->dev, buf->size, buf->vaddr,
		buf->dma_addr);
		kfree(buf);
		}

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