[media] media: Determine early whether an IOCTL is supported

Preparation for refactoring media IOCTL handling to unify common parts.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 1795abeda658..f3212640858b 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -419,6 +419,22 @@ static long media_device_get_topology(struct media_device *mdev,
         return 0;
 }
 
+#define MEDIA_IOC(__cmd) \
+        [_IOC_NR(MEDIA_IOC_##__cmd)] = { .cmd = MEDIA_IOC_##__cmd }
+
+/* the table is indexed by _IOC_NR(cmd) */
+struct media_ioctl_info {
+        unsigned int cmd;
+};
+
+static const struct media_ioctl_info ioctl_info[] = {
+        MEDIA_IOC(DEVICE_INFO),
+        MEDIA_IOC(ENUM_ENTITIES),
+        MEDIA_IOC(ENUM_LINKS),
+        MEDIA_IOC(SETUP_LINK),
+        MEDIA_IOC(G_TOPOLOGY),
+};
+
 static long media_device_ioctl(struct file *filp, unsigned int cmd,
                                unsigned long arg)
 {
@@ -426,6 +442,10 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
         struct media_device *dev = devnode->media_dev;
         long ret;
 
+        if (_IOC_NR(cmd) >= ARRAY_SIZE(ioctl_info)
+            || ioctl_info[_IOC_NR(cmd)].cmd != cmd)
+                return -ENOIOCTLCMD;
+
         mutex_lock(&dev->graph_mutex);
         switch (cmd) {
         case MEDIA_IOC_DEVICE_INFO: