[media] v4l2-ioctl.c: introduce INFO_FL_CLEAR to replace switch

The switch statement that determines how much data should be copied from
userspace is replaced by a table lookup.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 41 insertions, 62 deletions

diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 46fd95327630..e2f77bc15954 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -394,7 +394,7 @@ static int check_fmt(const struct v4l2_ioctl_ops *ops, enum v4l2_buf_type type)
 
 struct v4l2_ioctl_info {
         unsigned int ioctl;
-        u16 flags;
+        u32 flags;
         const char * const name;
 };
 
@@ -402,6 +402,11 @@ struct v4l2_ioctl_info {
 #define INFO_FL_PRIO    (1 << 0)
 /* This control can be valid if the filehandle passes a control handler. */
 #define INFO_FL_CTRL    (1 << 1)
+/* Zero struct from after the field to the end */
+#define INFO_FL_CLEAR(v4l2_struct, field)                       \
+        ((offsetof(struct v4l2_struct, field) +                 \
+          sizeof(((struct v4l2_struct *)0)->field)) << 16)
+#define INFO_FL_CLEAR_MASK (_IOC_SIZEMASK << 16)
 
 #define IOCTL_INFO(_ioctl, _flags) [_IOC_NR(_ioctl)] = {        \
         .ioctl = _ioctl,                                        \
@@ -411,11 +416,11 @@ struct v4l2_ioctl_info {
 
 static struct v4l2_ioctl_info v4l2_ioctls[] = {
         IOCTL_INFO(VIDIOC_QUERYCAP, 0),
-        IOCTL_INFO(VIDIOC_ENUM_FMT, 0),
-        IOCTL_INFO(VIDIOC_G_FMT, 0),
+        IOCTL_INFO(VIDIOC_ENUM_FMT, INFO_FL_CLEAR(v4l2_fmtdesc, type)),
+        IOCTL_INFO(VIDIOC_G_FMT, INFO_FL_CLEAR(v4l2_format, type)),
         IOCTL_INFO(VIDIOC_S_FMT, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_REQBUFS, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_QUERYBUF, 0),
+        IOCTL_INFO(VIDIOC_QUERYBUF, INFO_FL_CLEAR(v4l2_buffer, length)),
         IOCTL_INFO(VIDIOC_G_FBUF, 0),
         IOCTL_INFO(VIDIOC_S_FBUF, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_OVERLAY, INFO_FL_PRIO),
@@ -423,33 +428,33 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
         IOCTL_INFO(VIDIOC_DQBUF, 0),
         IOCTL_INFO(VIDIOC_STREAMON, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_STREAMOFF, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_G_PARM, 0),
+        IOCTL_INFO(VIDIOC_G_PARM, INFO_FL_CLEAR(v4l2_streamparm, type)),
         IOCTL_INFO(VIDIOC_S_PARM, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_G_STD, 0),
         IOCTL_INFO(VIDIOC_S_STD, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_ENUMSTD, 0),
-        IOCTL_INFO(VIDIOC_ENUMINPUT, 0),
+        IOCTL_INFO(VIDIOC_ENUMSTD, INFO_FL_CLEAR(v4l2_standard, index)),
+        IOCTL_INFO(VIDIOC_ENUMINPUT, INFO_FL_CLEAR(v4l2_input, index)),
         IOCTL_INFO(VIDIOC_G_CTRL, INFO_FL_CTRL),
         IOCTL_INFO(VIDIOC_S_CTRL, INFO_FL_PRIO | INFO_FL_CTRL),
-        IOCTL_INFO(VIDIOC_G_TUNER, 0),
+        IOCTL_INFO(VIDIOC_G_TUNER, INFO_FL_CLEAR(v4l2_tuner, index)),
         IOCTL_INFO(VIDIOC_S_TUNER, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_G_AUDIO, 0),
         IOCTL_INFO(VIDIOC_S_AUDIO, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_QUERYCTRL, INFO_FL_CTRL),
-        IOCTL_INFO(VIDIOC_QUERYMENU, INFO_FL_CTRL),
+        IOCTL_INFO(VIDIOC_QUERYCTRL, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_queryctrl, id)),
+        IOCTL_INFO(VIDIOC_QUERYMENU, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_querymenu, index)),
         IOCTL_INFO(VIDIOC_G_INPUT, 0),
         IOCTL_INFO(VIDIOC_S_INPUT, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_G_OUTPUT, 0),
+        IOCTL_INFO(VIDIOC_G_OUTPUT, INFO_FL_CLEAR(v4l2_output, index)),
         IOCTL_INFO(VIDIOC_S_OUTPUT, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_ENUMOUTPUT, 0),
         IOCTL_INFO(VIDIOC_G_AUDOUT, 0),
         IOCTL_INFO(VIDIOC_S_AUDOUT, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_G_MODULATOR, 0),
+        IOCTL_INFO(VIDIOC_G_MODULATOR, INFO_FL_CLEAR(v4l2_modulator, index)),
         IOCTL_INFO(VIDIOC_S_MODULATOR, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_G_FREQUENCY, 0),
+        IOCTL_INFO(VIDIOC_G_FREQUENCY, INFO_FL_CLEAR(v4l2_frequency, tuner)),
         IOCTL_INFO(VIDIOC_S_FREQUENCY, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_CROPCAP, 0),
-        IOCTL_INFO(VIDIOC_G_CROP, 0),
+        IOCTL_INFO(VIDIOC_CROPCAP, INFO_FL_CLEAR(v4l2_cropcap, type)),
+        IOCTL_INFO(VIDIOC_G_CROP, INFO_FL_CLEAR(v4l2_crop, type)),
         IOCTL_INFO(VIDIOC_S_CROP, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_G_SELECTION, 0),
         IOCTL_INFO(VIDIOC_S_SELECTION, INFO_FL_PRIO),
@@ -457,20 +462,20 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
         IOCTL_INFO(VIDIOC_S_JPEGCOMP, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_QUERYSTD, 0),
         IOCTL_INFO(VIDIOC_TRY_FMT, 0),
-        IOCTL_INFO(VIDIOC_ENUMAUDIO, 0),
-        IOCTL_INFO(VIDIOC_ENUMAUDOUT, 0),
+        IOCTL_INFO(VIDIOC_ENUMAUDIO, INFO_FL_CLEAR(v4l2_audio, index)),
+        IOCTL_INFO(VIDIOC_ENUMAUDOUT, INFO_FL_CLEAR(v4l2_audioout, index)),
         IOCTL_INFO(VIDIOC_G_PRIORITY, 0),
         IOCTL_INFO(VIDIOC_S_PRIORITY, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_G_SLICED_VBI_CAP, 0),
+        IOCTL_INFO(VIDIOC_G_SLICED_VBI_CAP, INFO_FL_CLEAR(v4l2_sliced_vbi_cap, type)),
         IOCTL_INFO(VIDIOC_LOG_STATUS, 0),
         IOCTL_INFO(VIDIOC_G_EXT_CTRLS, INFO_FL_CTRL),
         IOCTL_INFO(VIDIOC_S_EXT_CTRLS, INFO_FL_PRIO | INFO_FL_CTRL),
         IOCTL_INFO(VIDIOC_TRY_EXT_CTRLS, 0),
-        IOCTL_INFO(VIDIOC_ENUM_FRAMESIZES, 0),
-        IOCTL_INFO(VIDIOC_ENUM_FRAMEINTERVALS, 0),
+        IOCTL_INFO(VIDIOC_ENUM_FRAMESIZES, INFO_FL_CLEAR(v4l2_frmsizeenum, pixel_format)),
+        IOCTL_INFO(VIDIOC_ENUM_FRAMEINTERVALS, INFO_FL_CLEAR(v4l2_frmivalenum, height)),
         IOCTL_INFO(VIDIOC_G_ENC_INDEX, 0),
-        IOCTL_INFO(VIDIOC_ENCODER_CMD, INFO_FL_PRIO),
-        IOCTL_INFO(VIDIOC_TRY_ENCODER_CMD, 0),
+        IOCTL_INFO(VIDIOC_ENCODER_CMD, INFO_FL_PRIO | INFO_FL_CLEAR(v4l2_encoder_cmd, flags)),
+        IOCTL_INFO(VIDIOC_TRY_ENCODER_CMD, INFO_FL_CLEAR(v4l2_encoder_cmd, flags)),
         IOCTL_INFO(VIDIOC_DECODER_CMD, INFO_FL_PRIO),
         IOCTL_INFO(VIDIOC_TRY_DECODER_CMD, 0),
 #ifdef CONFIG_VIDEO_ADV_DEBUG
@@ -2106,45 +2111,6 @@ static long __video_do_ioctl(struct file *file,
         return ret;
 }
 
-/* In some cases, only a few fields are used as input, i.e. when the app sets
- * "index" and then the driver fills in the rest of the structure for the thing
- * with that index.  We only need to copy up the first non-input field.  */
-static unsigned long cmd_input_size(unsigned int cmd)
-{
-        /* Size of structure up to and including 'field' */
-#define CMDINSIZE(cmd, type, field)                             \
-        case VIDIOC_##cmd:                                      \
-                return offsetof(struct v4l2_##type, field) +    \
-                        sizeof(((struct v4l2_##type *)0)->field);
-
-        switch (cmd) {
-                CMDINSIZE(ENUM_FMT,             fmtdesc,        type);
-                CMDINSIZE(G_FMT,                format,         type);
-                CMDINSIZE(QUERYBUF,             buffer,         length);
-                CMDINSIZE(G_PARM,               streamparm,     type);
-                CMDINSIZE(ENUMSTD,              standard,       index);
-                CMDINSIZE(ENUMINPUT,            input,          index);
-                CMDINSIZE(G_CTRL,               control,        id);
-                CMDINSIZE(G_TUNER,              tuner,          index);
-                CMDINSIZE(QUERYCTRL,            queryctrl,      id);
-                CMDINSIZE(QUERYMENU,            querymenu,      index);
-                CMDINSIZE(ENUMOUTPUT,           output,         index);
-                CMDINSIZE(G_MODULATOR,          modulator,      index);
-                CMDINSIZE(G_FREQUENCY,          frequency,      tuner);
-                CMDINSIZE(CROPCAP,              cropcap,        type);
-                CMDINSIZE(G_CROP,               crop,           type);
-                CMDINSIZE(ENUMAUDIO,            audio,          index);
-                CMDINSIZE(ENUMAUDOUT,           audioout,       index);
-                CMDINSIZE(ENCODER_CMD,          encoder_cmd,    flags);
-                CMDINSIZE(TRY_ENCODER_CMD,      encoder_cmd,    flags);
-                CMDINSIZE(G_SLICED_VBI_CAP,     sliced_vbi_cap, type);
-                CMDINSIZE(ENUM_FRAMESIZES,      frmsizeenum,    pixel_format);
-                CMDINSIZE(ENUM_FRAMEINTERVALS,  frmivalenum,    height);
-        default:
-                return _IOC_SIZE(cmd);
-        }
-}
-
 static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
                             void * __user *user_ptr, void ***kernel_ptr)
 {
@@ -2219,7 +2185,20 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
 
                 err = -EFAULT;
                 if (_IOC_DIR(cmd) & _IOC_WRITE) {
-                        unsigned long n = cmd_input_size(cmd);
+                        unsigned int n = _IOC_SIZE(cmd);
+
+                        /*
+                         * In some cases, only a few fields are used as input,
+                         * i.e. when the app sets "index" and then the driver
+                         * fills in the rest of the structure for the thing
+                         * with that index.  We only need to copy up the first
+                         * non-input field.
+                         */
+                        if (v4l2_is_known_ioctl(cmd)) {
+                                u32 flags = v4l2_ioctls[_IOC_NR(cmd)].flags;
+                                if (flags & INFO_FL_CLEAR_MASK)
+                                        n = (flags & INFO_FL_CLEAR_MASK) >> 16;
+                        }
 
                         if (copy_from_user(parg, (void __user *)arg, n))
                                 goto out;