media: Wrap file->private_data access with a helper function

Accessing file->private_data manually to retrieve the v4l2_fh pointer is
error-prone, as the field is a void * and will happily convert
implicitly to any pointer type. To avoid direct access to
file->private_data, introduce a new inline function that retrieves the
v4l2_fh pointer, and use it to replace common access patterns through
the kernel.

Changes to drivers have been generated with the following coccinelle
semantic patch:

@@
struct file *filp;
identifier fh;
@@

-       struct v4l2_fh *fh = filp->private_data;
+       struct v4l2_fh *fh = file_to_v4l2_fh(filp);

Manual changes have been applied to Documentation/ to update the usage
patterns, and to include/media/v4l2-fh.h to add the new function.

While at it, fix a typo in the title of v4l2-fh.rst: the file describes
the "file handles" API, not "file handlers".

No functional change is intended, this only paves the way to remove
direct accesses to file->private_data and make V4L2 drivers safer.
Other accesses to the field will be addressed separately.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

8 files changed, 20 insertions, 20 deletions

diff --git a/drivers/media/platform/allegro-dvt/allegro-core.c b/drivers/media/platform/allegro-dvt/allegro-core.c
index eb03df0d8652..1f134e08923a 100644
--- a/drivers/media/platform/allegro-dvt/allegro-core.c
+++ b/drivers/media/platform/allegro-dvt/allegro-core.c
@@ -3483,7 +3483,7 @@ static int allegro_enum_framesizes(struct file *file, void *fh,
 static int allegro_ioctl_streamon(struct file *file, void *priv,
 				  enum v4l2_buf_type type)
 {
-	struct v4l2_fh *fh = file->private_data;
+	struct v4l2_fh *fh = file_to_v4l2_fh(file);
 	struct allegro_channel *channel = fh_to_channel(fh);
 	int err;
 
diff --git a/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c b/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
index 7eb12449b63a..329e5787c2c2 100644
--- a/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
+++ b/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
@@ -588,7 +588,7 @@ static int mtk_jpeg_enc_s_selection(struct file *file, void *priv,
 
 static int mtk_jpeg_qbuf(struct file *file, void *priv, struct v4l2_buffer *buf)
 {
-	struct v4l2_fh *fh = file->private_data;
+	struct v4l2_fh *fh = file_to_v4l2_fh(file);
 	struct mtk_jpeg_ctx *ctx = mtk_jpeg_fh_to_ctx(priv);
 	struct vb2_queue *vq;
 	struct vb2_buffer *vb;
diff --git a/drivers/media/platform/nvidia/tegra-vde/v4l2.c b/drivers/media/platform/nvidia/tegra-vde/v4l2.c
index e3726cab0c82..531a85e3fe49 100644
--- a/drivers/media/platform/nvidia/tegra-vde/v4l2.c
+++ b/drivers/media/platform/nvidia/tegra-vde/v4l2.c
@@ -853,7 +853,7 @@ free_ctx:
 
 static int tegra_release(struct file *file)
 {
-	struct v4l2_fh *fh = file->private_data;
+	struct v4l2_fh *fh = file_to_v4l2_fh(file);
 	struct tegra_ctx *ctx = fh_to_tegra_ctx(fh);
 	struct tegra_vde *vde = ctx->vde;
 
diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
index 8681dd193033..1b2148578cb6 100644
--- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
+++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
@@ -1604,7 +1604,7 @@ end:
 static int mxc_jpeg_decoder_cmd(struct file *file, void *priv,
 				struct v4l2_decoder_cmd *cmd)
 {
-	struct v4l2_fh *fh = file->private_data;
+	struct v4l2_fh *fh = file_to_v4l2_fh(file);
 	struct mxc_jpeg_ctx *ctx = mxc_jpeg_fh_to_ctx(fh);
 	unsigned long flags;
 	int ret;
@@ -1637,7 +1637,7 @@ static int mxc_jpeg_decoder_cmd(struct file *file, void *priv,
 static int mxc_jpeg_encoder_cmd(struct file *file, void *priv,
 				struct v4l2_encoder_cmd *cmd)
 {
-	struct v4l2_fh *fh = file->private_data;
+	struct v4l2_fh *fh = file_to_v4l2_fh(file);
 	struct mxc_jpeg_ctx *ctx = mxc_jpeg_fh_to_ctx(fh);
 	unsigned long flags;
 	int ret;
diff --git a/drivers/media/platform/renesas/vsp1/vsp1_histo.c b/drivers/media/platform/renesas/vsp1/vsp1_histo.c
index c762202877ba..390ea50f1595 100644
--- a/drivers/media/platform/renesas/vsp1/vsp1_histo.c
+++ b/drivers/media/platform/renesas/vsp1/vsp1_histo.c
@@ -392,7 +392,7 @@ static const struct v4l2_subdev_ops histo_ops = {
 static int histo_v4l2_querycap(struct file *file, void *fh,
 			       struct v4l2_capability *cap)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_histogram *histo = vdev_to_histo(vfh->vdev);
 
 	cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING
@@ -409,7 +409,7 @@ static int histo_v4l2_querycap(struct file *file, void *fh,
 static int histo_v4l2_enum_format(struct file *file, void *fh,
 				  struct v4l2_fmtdesc *f)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_histogram *histo = vdev_to_histo(vfh->vdev);
 
 	if (f->index > 0 || f->type != histo->queue.type)
@@ -423,7 +423,7 @@ static int histo_v4l2_enum_format(struct file *file, void *fh,
 static int histo_v4l2_get_format(struct file *file, void *fh,
 				 struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_histogram *histo = vdev_to_histo(vfh->vdev);
 	struct v4l2_meta_format *meta = &format->fmt.meta;
 
diff --git a/drivers/media/platform/renesas/vsp1/vsp1_video.c b/drivers/media/platform/renesas/vsp1/vsp1_video.c
index bc66fbdde3cc..656fb5e6cb30 100644
--- a/drivers/media/platform/renesas/vsp1/vsp1_video.c
+++ b/drivers/media/platform/renesas/vsp1/vsp1_video.c
@@ -896,7 +896,7 @@ static const struct vb2_ops vsp1_video_queue_qops = {
 static int
 vsp1_video_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_video *video = to_vsp1_video(vfh->vdev);
 
 	cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING
@@ -912,7 +912,7 @@ vsp1_video_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
 static int vsp1_video_enum_format(struct file *file, void *fh,
 				  struct v4l2_fmtdesc *f)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_video *video = to_vsp1_video(vfh->vdev);
 	const struct vsp1_format_info *info;
 
@@ -933,7 +933,7 @@ static int vsp1_video_enum_format(struct file *file, void *fh,
 static int
 vsp1_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_video *video = to_vsp1_video(vfh->vdev);
 
 	if (format->type != video->queue.type)
@@ -949,7 +949,7 @@ vsp1_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
 static int
 vsp1_video_try_format(struct file *file, void *fh, struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_video *video = to_vsp1_video(vfh->vdev);
 
 	if (format->type != video->queue.type)
@@ -961,7 +961,7 @@ vsp1_video_try_format(struct file *file, void *fh, struct v4l2_format *format)
 static int
 vsp1_video_set_format(struct file *file, void *fh, struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_video *video = to_vsp1_video(vfh->vdev);
 	const struct vsp1_format_info *info;
 	int ret;
@@ -991,7 +991,7 @@ done:
 static int
 vsp1_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct vsp1_video *video = to_vsp1_video(vfh->vdev);
 	struct media_device *mdev = &video->vsp1->media_dev;
 	struct vsp1_pipeline *pipe;
diff --git a/drivers/media/platform/ti/omap3isp/ispvideo.c b/drivers/media/platform/ti/omap3isp/ispvideo.c
index 78e30298c7ad..a777135c6a6c 100644
--- a/drivers/media/platform/ti/omap3isp/ispvideo.c
+++ b/drivers/media/platform/ti/omap3isp/ispvideo.c
@@ -1348,7 +1348,7 @@ done:
 static int isp_video_release(struct file *file)
 {
 	struct isp_video *video = video_drvdata(file);
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct isp_video_fh *handle = to_isp_video_fh(vfh);
 
 	/* Disable streaming and free the buffers queue resources. */
diff --git a/drivers/media/platform/xilinx/xilinx-dma.c b/drivers/media/platform/xilinx/xilinx-dma.c
index 18bfa6001909..fcfe0883aba5 100644
--- a/drivers/media/platform/xilinx/xilinx-dma.c
+++ b/drivers/media/platform/xilinx/xilinx-dma.c
@@ -469,7 +469,7 @@ static const struct vb2_ops xvip_dma_queue_qops = {
 static int
 xvip_dma_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct xvip_dma *dma = to_xvip_dma(vfh->vdev);
 
 	cap->capabilities = dma->xdev->v4l2_caps | V4L2_CAP_STREAMING |
@@ -491,7 +491,7 @@ xvip_dma_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
 static int
 xvip_dma_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct xvip_dma *dma = to_xvip_dma(vfh->vdev);
 
 	if (f->index > 0)
@@ -505,7 +505,7 @@ xvip_dma_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
 static int
 xvip_dma_get_format(struct file *file, void *fh, struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct xvip_dma *dma = to_xvip_dma(vfh->vdev);
 
 	format->fmt.pix = dma->format;
@@ -565,7 +565,7 @@ __xvip_dma_try_format(struct xvip_dma *dma, struct v4l2_pix_format *pix,
 static int
 xvip_dma_try_format(struct file *file, void *fh, struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct xvip_dma *dma = to_xvip_dma(vfh->vdev);
 
 	__xvip_dma_try_format(dma, &format->fmt.pix, NULL);
@@ -575,7 +575,7 @@ xvip_dma_try_format(struct file *file, void *fh, struct v4l2_format *format)
 static int
 xvip_dma_set_format(struct file *file, void *fh, struct v4l2_format *format)
 {
-	struct v4l2_fh *vfh = file->private_data;
+	struct v4l2_fh *vfh = file_to_v4l2_fh(file);
 	struct xvip_dma *dma = to_xvip_dma(vfh->vdev);
 	const struct xvip_video_format *info;