[PATCH v3 4/4] media: uvcvideo: RFC: Convert allow_privacy_override into Kconfig

[Ricardo Ribalda <ribalda@chromium.org>]

This patch is just shared for discussion purposes! Do not land.

In a perfect world, after a deprecation process, we will be able to
remove allow_privacy_override and block all privacy related controls.

If there is any usecase out in the field that resists, we shall move it
into a Kconfig.

This patch shows how the transition to Kconfig can look.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/Kconfig      | 11 +++++++++++
 drivers/media/usb/uvc/uvc_ctrl.c   |  4 ++--
 drivers/media/usb/uvc/uvc_driver.c | 20 --------------------
 drivers/media/usb/uvc/uvc_v4l2.c   |  4 ++--
 drivers/media/usb/uvc/uvcvideo.h   |  1 -
 5 files changed, 15 insertions(+), 25 deletions(-)

diff --git a/drivers/media/usb/uvc/Kconfig b/drivers/media/usb/uvc/Kconfig
index 579532272fd6..7c0f2260d135 100644
--- a/drivers/media/usb/uvc/Kconfig
+++ b/drivers/media/usb/uvc/Kconfig
@@ -20,3 +20,14 @@ config USB_VIDEO_CLASS_INPUT_EVDEV
 	  to report button events.
 
 	  If you are in doubt, say Y.
+
+config USB_VIDEO_CLASS_ALLOW_PRIVACY_OVERRIDE
+	bool "Allow overriding the privacy controls"
+	default n
+	depends on USB_VIDEO_CLASS && BROKEN
+	help
+	  If this option is enabled, the privacy related controls, such as
+	  the ones controlling the privacy LED will be accessible from
+	  userspace.
+
+	  If you are in doubt, say N.
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 3ca108b83f1d..c9c195974765 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -3075,9 +3075,9 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
 	}
 
 	if (uvc_ctrl_is_privacy_control(entity->guid, xqry->selector) &&
-	    !uvc_allow_privacy_override_param) {
+	    !IS_ENABLED(CONFIG_USB_VIDEO_CLASS_ALLOW_PRIVACY_OVERRIDE)) {
 		dev_warn_once(&chain->dev->intf->dev,
-			      "Privacy related controls can only be accessed if module parameter allow_privacy_override is true\n");
+			      "Privacy related controls can only be accessed if CONFIG_USB_VIDEO_CLASS_ALLOW_PRIVACY_OVERRIDE is true\n");
 		uvc_dbg(chain->dev, CONTROL, "Blocking access to privacy related Control %pUl/%u\n",
 			entity->guid, xqry->selector);
 		return -EACCES;
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 74c9dea29d36..b0ca81d924b6 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -36,7 +36,6 @@ unsigned int uvc_no_drop_param = 1;
 static unsigned int uvc_quirks_param = -1;
 unsigned int uvc_dbg_param;
 unsigned int uvc_timeout_param = UVC_CTRL_STREAMING_TIMEOUT;
-bool uvc_allow_privacy_override_param;
 
 static struct usb_driver uvc_driver;
 
@@ -2506,25 +2505,6 @@ MODULE_PARM_DESC(trace, "Trace level bitmask");
 module_param_named(timeout, uvc_timeout_param, uint, 0644);
 MODULE_PARM_DESC(timeout, "Streaming control requests timeout");
 
-static int param_set_privacy(const char *val, const struct kernel_param *kp)
-{
-	pr_warn_once("uvcvideo: " DEPRECATED
-		     "allow_privacy_override parameter will be eventually removed.\n");
-	return param_set_bool(val, kp);
-}
-
-static const struct kernel_param_ops param_ops_privacy = {
-	.set = param_set_privacy,
-	.get = param_get_bool,
-};
-
-param_check_bool(allow_privacy_override, &uvc_allow_privacy_override_param);
-module_param_cb(allow_privacy_override, &param_ops_privacy,
-		&uvc_allow_privacy_override_param, 0644);
-__MODULE_PARM_TYPE(allow_privacy_override, "bool");
-MODULE_PARM_DESC(allow_privacy_override,
-		 "Allow access to privacy related controls");
-
 /* ------------------------------------------------------------------------
  * Driver initialization and cleanup
  */
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 6d4f027c8402..f83abbd13aca 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -134,9 +134,9 @@ static int uvc_ioctl_xu_ctrl_map(struct uvc_video_chain *chain,
 	}
 
 	if (uvc_ctrl_is_privacy_control(xmap->entity, xmap->selector) &&
-	    !uvc_allow_privacy_override_param) {
+	    !IS_ENABLED(CONFIG_USB_VIDEO_CLASS_ALLOW_PRIVACY_OVERRIDE)) {
 		dev_warn_once(&chain->dev->intf->dev,
-			      "Privacy related controls can only be mapped if module parameter allow_privacy_override is true\n");
+			      "Privacy related controls can only be mapped if CONFIG_USB_VIDEO_CLASS_ALLOW_PRIVACY_OVERRIDE is true\n");
 		return -EACCES;
 	}
 
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 362110d58ca3..2898384d5f78 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -664,7 +664,6 @@ extern unsigned int uvc_no_drop_param;
 extern unsigned int uvc_dbg_param;
 extern unsigned int uvc_timeout_param;
 extern unsigned int uvc_hw_timestamps_param;
-extern bool uvc_allow_privacy_override_param;
 
 #define uvc_dbg(_dev, flag, fmt, ...)					\
 do {									\

-- 
2.53.0.851.ga537e3e6e9-goog