[media] v4l2-ctrls: fix sparse warning

The warning is simple:

drivers/media/v4l2-core/v4l2-ctrls.c:1685:15: warning: incorrect type in assignment (different address spaces)

but the fix isn't.

The core problem was that the conversion from user to kernelspace was
done at too low a level and that needed to be moved up. That made it possible
to drop pointers to v4l2_ext_control from set_ctrl and validate_new and
clean up this sparse warning because those functions now always operate
on kernelspace pointers.

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

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 86012140923fcf57526952c975a9516084f174f1..45c5b47106012db96ca667fd74303fdd677dafe1 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1658,10 +1658,8 @@ static int check_range(enum v4l2_ctrl_type type,
 }
 
 /* Validate a new control */
-static int validate_new(const struct v4l2_ctrl *ctrl,
-                       struct v4l2_ext_control *c)
+static int validate_new(const struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr p_new)
 {
-       union v4l2_ctrl_ptr ptr;
        unsigned idx;
        int err = 0;
 
@@ -1674,19 +1672,14 @@ static int validate_new(const struct v4l2_ctrl *ctrl,
                case V4L2_CTRL_TYPE_BOOLEAN:
                case V4L2_CTRL_TYPE_BUTTON:
                case V4L2_CTRL_TYPE_CTRL_CLASS:
-                       ptr.p_s32 = &c->value;
-                       return ctrl->type_ops->validate(ctrl, 0, ptr);
-
                case V4L2_CTRL_TYPE_INTEGER64:
-                       ptr.p_s64 = &c->value64;
-                       return ctrl->type_ops->validate(ctrl, 0, ptr);
+                       return ctrl->type_ops->validate(ctrl, 0, p_new);
                default:
                        break;
                }
        }
-       ptr.p = c->ptr;
-       for (idx = 0; !err && idx < c->size / ctrl->elem_size; idx++)
-               err = ctrl->type_ops->validate(ctrl, idx, ptr);
+       for (idx = 0; !err && idx < ctrl->elems; idx++)
+               err = ctrl->type_ops->validate(ctrl, idx, p_new);
        return err;
 }
 
@@ -3012,6 +3005,7 @@ static int validate_ctrls(struct v4l2_ext_controls *cs,
        cs->error_idx = cs->count;
        for (i = 0; i < cs->count; i++) {
                struct v4l2_ctrl *ctrl = helpers[i].ctrl;
+               union v4l2_ctrl_ptr p_new;
 
                cs->error_idx = i;
 
@@ -3025,7 +3019,17 @@ static int validate_ctrls(struct v4l2_ext_controls *cs,
                   best-effort to avoid that. */
                if (set && (ctrl->flags & V4L2_CTRL_FLAG_GRABBED))
                        return -EBUSY;
-               ret = validate_new(ctrl, &cs->controls[i]);
+               /*
+                * Skip validation for now if the payload needs to be copied
+                * from userspace into kernelspace. We'll validate those later.
+                */
+               if (ctrl->is_ptr)
+                       continue;
+               if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
+                       p_new.p_s64 = &cs->controls[i].value64;
+               else
+                       p_new.p_s32 = &cs->controls[i].value;
+               ret = validate_new(ctrl, p_new);
                if (ret)
                        return ret;
        }
@@ -3120,7 +3124,11 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
                /* Copy the new caller-supplied control values.
                   user_to_new() sets 'is_new' to 1. */
                do {
-                       ret = user_to_new(cs->controls + idx, helpers[idx].ctrl);
+                       struct v4l2_ctrl *ctrl = helpers[idx].ctrl;
+
+                       ret = user_to_new(cs->controls + idx, ctrl);
+                       if (!ret && ctrl->is_ptr)
+                               ret = validate_new(ctrl, ctrl->p_new);
                        idx = helpers[idx].next;
                } while (!ret && idx);
 
@@ -3170,10 +3178,10 @@ int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs
 EXPORT_SYMBOL(v4l2_subdev_s_ext_ctrls);
 
 /* Helper function for VIDIOC_S_CTRL compatibility */
-static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl,
-                   struct v4l2_ext_control *c, u32 ch_flags)
+static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, u32 ch_flags)
 {
        struct v4l2_ctrl *master = ctrl->cluster[0];
+       int ret;
        int i;
 
        /* Reset the 'is_new' flags of the cluster */
@@ -3181,8 +3189,9 @@ static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl,
                if (master->cluster[i])
                        master->cluster[i]->is_new = 0;
 
-       if (c)
-               user_to_new(c, ctrl);
+       ret = validate_new(ctrl, ctrl->p_new);
+       if (ret)
+               return ret;
 
        /* For autoclusters with volatiles that are switched from auto to
           manual mode we have to update the current volatile values since
@@ -3199,15 +3208,14 @@ static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl,
 static int set_ctrl_lock(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl,
                         struct v4l2_ext_control *c)
 {
-       int ret = validate_new(ctrl, c);
+       int ret;
 
-       if (!ret) {
-               v4l2_ctrl_lock(ctrl);
-               ret = set_ctrl(fh, ctrl, c, 0);
-               if (!ret)
-                       cur_to_user(c, ctrl);
-               v4l2_ctrl_unlock(ctrl);
-       }
+       v4l2_ctrl_lock(ctrl);
+       user_to_new(c, ctrl);
+       ret = set_ctrl(fh, ctrl, 0);
+       if (!ret)
+               cur_to_user(c, ctrl);
+       v4l2_ctrl_unlock(ctrl);
        return ret;
 }
 
@@ -3215,7 +3223,7 @@ int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
                                        struct v4l2_control *control)
 {
        struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, control->id);
-       struct v4l2_ext_control c;
+       struct v4l2_ext_control c = { control->id };
        int ret;
 
        if (ctrl == NULL || !ctrl->is_int)
@@ -3244,7 +3252,7 @@ int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
        /* It's a driver bug if this happens. */
        WARN_ON(!ctrl->is_int);
        ctrl->val = val;
-       return set_ctrl(NULL, ctrl, NULL, 0);
+       return set_ctrl(NULL, ctrl, 0);
 }
 EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl);
 
@@ -3255,7 +3263,7 @@ int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
        /* It's a driver bug if this happens. */
        WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64);
        *ctrl->p_new.p_s64 = val;
-       return set_ctrl(NULL, ctrl, NULL, 0);
+       return set_ctrl(NULL, ctrl, 0);
 }
 EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_int64);
 
@@ -3266,7 +3274,7 @@ int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
        /* It's a driver bug if this happens. */
        WARN_ON(ctrl->type != V4L2_CTRL_TYPE_STRING);
        strlcpy(ctrl->p_new.p_char, s, ctrl->maximum + 1);
-       return set_ctrl(NULL, ctrl, NULL, 0);
+       return set_ctrl(NULL, ctrl, 0);
 }
 EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_string);
 
@@ -3289,8 +3297,8 @@ EXPORT_SYMBOL(v4l2_ctrl_notify);
 int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
                        s64 min, s64 max, u64 step, s64 def)
 {
+       bool changed;
        int ret;
-       struct v4l2_ext_control c;
 
        lockdep_assert_held(ctrl->handler->lock);
 
@@ -3317,11 +3325,20 @@ int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
        ctrl->maximum = max;
        ctrl->step = step;
        ctrl->default_value = def;
-       c.value = *ctrl->p_cur.p_s32;
-       if (validate_new(ctrl, &c))
-               c.value = def;
-       if (c.value != *ctrl->p_cur.p_s32)
-               ret = set_ctrl(NULL, ctrl, &c, V4L2_EVENT_CTRL_CH_RANGE);
+       cur_to_new(ctrl);
+       if (validate_new(ctrl, ctrl->p_new)) {
+               if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
+                       *ctrl->p_new.p_s64 = def;
+               else
+                       *ctrl->p_new.p_s32 = def;
+       }
+
+       if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
+               changed = *ctrl->p_new.p_s64 != *ctrl->p_cur.p_s64;
+       else
+               changed = *ctrl->p_new.p_s32 != *ctrl->p_cur.p_s32;
+       if (changed)
+               ret = set_ctrl(NULL, ctrl, V4L2_EVENT_CTRL_CH_RANGE);
        else
                send_event(NULL, ctrl, V4L2_EVENT_CTRL_CH_RANGE);
        return ret;