[media] v4l2-ctrls: rewrite copy routines to operate on union v4l2_ctrl_ptr

In order to implement array support and (for the future) configuration stores
we need to have more generic copy routines that all operate on the v4l2_ctrl_ptr
union. So instead of e.g. using ctrl->cur.string it uses ptr.p_char. This makes
e.g. cur_to_user generic so it can be used to copy any v4l2_ctrl_ptr value to
userspace, not just the (hardcoded) current value.

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

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 09e2c3a..e7e0bea 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1304,48 +1304,64 @@ static const struct v4l2_ctrl_type_ops std_type_ops = {
        .validate = std_validate,
 };
 
-/* Helper function: copy the current control value back to the caller */
-static int cur_to_user(struct v4l2_ext_control *c,
-                      struct v4l2_ctrl *ctrl)
+/* Helper function: copy the given control value back to the caller */
+static int ptr_to_user(struct v4l2_ext_control *c,
+                      struct v4l2_ctrl *ctrl,
+                      union v4l2_ctrl_ptr ptr)
 {
        u32 len;
 
        if (ctrl->is_ptr && !ctrl->is_string)
-               return copy_to_user(c->ptr, ctrl->cur.p, ctrl->elem_size);
+               return copy_to_user(c->ptr, ptr.p, ctrl->elem_size);
 
        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_STRING:
-               len = strlen(ctrl->cur.string);
+               len = strlen(ptr.p_char);
                if (c->size < len + 1) {
                        c->size = len + 1;
                        return -ENOSPC;
                }
-               return copy_to_user(c->string, ctrl->cur.string,
-                                               len + 1) ? -EFAULT : 0;
+               return copy_to_user(c->string, ptr.p_char, len + 1) ?
+                                                               -EFAULT : 0;
        case V4L2_CTRL_TYPE_INTEGER64:
-               c->value64 = ctrl->cur.val64;
+               c->value64 = *ptr.p_s64;
                break;
        default:
-               c->value = ctrl->cur.val;
+               c->value = *ptr.p_s32;
                break;
        }
        return 0;
 }
 
-/* Helper function: copy the caller-provider value as the new control value */
-static int user_to_new(struct v4l2_ext_control *c,
+/* Helper function: copy the current control value back to the caller */
+static int cur_to_user(struct v4l2_ext_control *c,
                       struct v4l2_ctrl *ctrl)
+{
+       return ptr_to_user(c, ctrl, ctrl->p_cur);
+}
+
+/* Helper function: copy the new control value back to the caller */
+static int new_to_user(struct v4l2_ext_control *c,
+                      struct v4l2_ctrl *ctrl)
+{
+       return ptr_to_user(c, ctrl, ctrl->p_new);
+}
+
+/* Helper function: copy the caller-provider value to the given control value */
+static int user_to_ptr(struct v4l2_ext_control *c,
+                      struct v4l2_ctrl *ctrl,
+                      union v4l2_ctrl_ptr ptr)
 {
        int ret;
        u32 size;
 
        ctrl->is_new = 1;
        if (ctrl->is_ptr && !ctrl->is_string)
-               return copy_from_user(ctrl->p, c->ptr, ctrl->elem_size);
+               return copy_from_user(ptr.p, c->ptr, ctrl->elem_size);
 
        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_INTEGER64:
-               ctrl->val64 = c->value64;
+               *ptr.p_s64 = c->value64;
                break;
        case V4L2_CTRL_TYPE_STRING:
                size = c->size;
@@ -1353,83 +1369,64 @@ static int user_to_new(struct v4l2_ext_control *c,
                        return -ERANGE;
                if (size > ctrl->maximum + 1)
                        size = ctrl->maximum + 1;
-               ret = copy_from_user(ctrl->string, c->string, size);
+               ret = copy_from_user(ptr.p_char, c->string, size);
                if (!ret) {
-                       char last = ctrl->string[size - 1];
+                       char last = ptr.p_char[size - 1];
 
-                       ctrl->string[size - 1] = 0;
+                       ptr.p_char[size - 1] = 0;
                        /* If the string was longer than ctrl->maximum,
                           then return an error. */
-                       if (strlen(ctrl->string) == ctrl->maximum && last)
+                       if (strlen(ptr.p_char) == ctrl->maximum && last)
                                return -ERANGE;
                }
                return ret ? -EFAULT : 0;
        default:
-               ctrl->val = c->value;
+               *ptr.p_s32 = c->value;
                break;
        }
        return 0;
 }
 
-/* Helper function: copy the new control value back to the caller */
-static int new_to_user(struct v4l2_ext_control *c,
+/* Helper function: copy the caller-provider value as the new control value */
+static int user_to_new(struct v4l2_ext_control *c,
                       struct v4l2_ctrl *ctrl)
 {
-       u32 len;
-
-       if (ctrl->is_ptr && !ctrl->is_string)
-               return copy_to_user(c->ptr, ctrl->p, ctrl->elem_size);
+       return user_to_ptr(c, ctrl, ctrl->p_new);
+}
 
+/* Copy the one value to another. */
+static void ptr_to_ptr(struct v4l2_ctrl *ctrl,
+                      union v4l2_ctrl_ptr from, union v4l2_ctrl_ptr to)
+{
+       if (ctrl == NULL)
+               return;
        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_STRING:
-               len = strlen(ctrl->string);
-               if (c->size < len + 1) {
-                       c->size = ctrl->maximum + 1;
-                       return -ENOSPC;
-               }
-               return copy_to_user(c->string, ctrl->string,
-                                               len + 1) ? -EFAULT : 0;
+               /* strings are always 0-terminated */
+               strcpy(to.p_char, from.p_char);
+               break;
        case V4L2_CTRL_TYPE_INTEGER64:
-               c->value64 = ctrl->val64;
+               *to.p_s64 = *from.p_s64;
                break;
        default:
-               c->value = ctrl->val;
+               if (ctrl->is_ptr)
+                       memcpy(to.p, from.p, ctrl->elem_size);
+               else
+                       *to.p_s32 = *from.p_s32;
                break;
        }
-       return 0;
 }
 
 /* Copy the new value to the current value. */
 static void new_to_cur(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, u32 ch_flags)
 {
-       bool changed = false;
+       bool changed;
 
        if (ctrl == NULL)
                return;
+       changed = !ctrl->type_ops->equal(ctrl, ctrl->p_cur, ctrl->p_new);
+       ptr_to_ptr(ctrl, ctrl->p_new, ctrl->p_cur);
 
-       switch (ctrl->type) {
-       case V4L2_CTRL_TYPE_BUTTON:
-               changed = true;
-               break;
-       case V4L2_CTRL_TYPE_STRING:
-               /* strings are always 0-terminated */
-               changed = strcmp(ctrl->string, ctrl->cur.string);
-               strcpy(ctrl->cur.string, ctrl->string);
-               break;
-       case V4L2_CTRL_TYPE_INTEGER64:
-               changed = ctrl->val64 != ctrl->cur.val64;
-               ctrl->cur.val64 = ctrl->val64;
-               break;
-       default:
-               if (ctrl->is_ptr) {
-                       changed = memcmp(ctrl->p, ctrl->cur.p, ctrl->elem_size);
-                       memcpy(ctrl->cur.p, ctrl->p, ctrl->elem_size);
-               } else {
-                       changed = ctrl->val != ctrl->cur.val;
-                       ctrl->cur.val = ctrl->val;
-               }
-               break;
-       }
        if (ch_flags & V4L2_EVENT_CTRL_CH_FLAGS) {
                /* Note: CH_FLAGS is only set for auto clusters. */
                ctrl->flags &=
@@ -1458,21 +1455,7 @@ static void cur_to_new(struct v4l2_ctrl *ctrl)
 {
        if (ctrl == NULL)
                return;
-       switch (ctrl->type) {
-       case V4L2_CTRL_TYPE_STRING:
-               /* strings are always 0-terminated */
-               strcpy(ctrl->string, ctrl->cur.string);
-               break;
-       case V4L2_CTRL_TYPE_INTEGER64:
-               ctrl->val64 = ctrl->cur.val64;
-               break;
-       default:
-               if (ctrl->is_ptr)
-                       memcpy(ctrl->p, ctrl->cur.p, ctrl->elem_size);
-               else
-                       ctrl->val = ctrl->cur.val;
-               break;
-       }
+       ptr_to_ptr(ctrl, ctrl->p_cur, ctrl->p_new);
 }
 
 /* Return non-zero if one or more of the controls in the cluster has a new