[PATCH v4 1/5] media: Determine early whether an IOCTL is supported

Sakari Ailus
2016-08-11T20:30:10Z

Preparation for refactoring media IOCTL handling to unify common parts.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
drivers/media/media-device.c | 54 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 1795abe..aedd64e 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -419,13 +419,41 @@ static long media_device_get_topology(struct media_device *mdev,
return 0;
}

-static long media_device_ioctl(struct file *filp, unsigned int cmd,
- unsigned long arg)
+#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 inline long is_valid_ioctl(const struct media_ioctl_info *info,
+ unsigned int cmd)
+{
+ return (_IOC_NR(cmd) >= ARRAY_SIZE(ioctl_info)
+ || info[_IOC_NR(cmd)].cmd != cmd) ? -ENOIOCTLCMD : 0;
+}
+
+static long __media_device_ioctl(
+ struct file *filp, unsigned int cmd, void __user *arg,
+ const struct media_ioctl_info *info_array)
{
struct media_devnode *devnode = media_devnode_data(filp);
struct media_device *dev = devnode->media_dev;
long ret;

+ ret = is_valid_ioctl(info_array, cmd);
+ if (ret)
+ return ret;
+
mutex_lock(&dev->graph_mutex);
switch (cmd) {
case MEDIA_IOC_DEVICE_INFO:
@@ -461,6 +489,13 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
return ret;
}

+static long media_device_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ return __media_device_ioctl(
+ filp, cmd, (void __user *)arg, ioctl_info);
+}
+
#ifdef CONFIG_COMPAT

struct media_links_enum32 {
@@ -491,6 +526,14 @@ static long media_device_enum_links32(struct media_device *mdev,

#define MEDIA_IOC_ENUM_LINKS32 _IOWR('|', 0x02, struct media_links_enum32)

+static const struct media_ioctl_info compat_ioctl_info[] = {
+ MEDIA_IOC(DEVICE_INFO),
+ MEDIA_IOC(ENUM_ENTITIES),
+ MEDIA_IOC(ENUM_LINKS32),
+ MEDIA_IOC(SETUP_LINK),
+ MEDIA_IOC(G_TOPOLOGY),
+};
+
static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
@@ -498,6 +541,13 @@ static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
struct media_device *dev = devnode->media_dev;
long ret;

+ /*
+ * The number of supported IOCTLs is the same for both regular and
+ * compat cases. Instead of passing the sizes around, ensure that
+ * they match.
+ */
+ BUILD_BUG_ON(ARRAY_SIZE(ioctl_info) != ARRAY_SIZE(compat_ioctl_info));
+
switch (cmd) {
case MEDIA_IOC_ENUM_LINKS32:
mutex_lock(&dev->graph_mutex);
--
2.7.4