media: uvcvideo: Use indexed loops in uvc_ctrl_init_ctrl()

As shown by the bug introduced in commit 86f7ef773156 ("media: uvcvideo:
Add support for per-device control mapping overrides"), the loop style
used by uvc_ctrl_init_ctrl() is error-prone. Rewrite the loops to use
indices instead.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 8c208db9600b46aeaee44d0994e9e8c08d6b9b35..5c33b0b7ef9ae9d94dee1d31ec354eeab35c7d35 100644 (file)
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -2411,10 +2411,9 @@ static void uvc_ctrl_prune_entity(struct uvc_device *dev,
 static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
                               struct uvc_control *ctrl)
 {
-       const struct uvc_control_info *info = uvc_ctrls;
-       const struct uvc_control_info *iend = info + ARRAY_SIZE(uvc_ctrls);
-       const struct uvc_control_mapping *mapping;
-       const struct uvc_control_mapping *mend;
+       const struct uvc_control_mapping *mappings;
+       unsigned int num_mappings;
+       unsigned int i;
 
        /*
         * XU controls initialization requires querying the device for control
@@ -2425,7 +2424,9 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
        if (UVC_ENTITY_TYPE(ctrl->entity) == UVC_VC_EXTENSION_UNIT)
                return;
 
-       for (; info < iend; ++info) {
+       for (i = 0; i < ARRAY_SIZE(uvc_ctrls); ++i) {
+               const struct uvc_control_info *info = &uvc_ctrls[i];
+
                if (uvc_entity_match_guid(ctrl->entity, info->entity) &&
                    ctrl->index == info->index) {
                        uvc_ctrl_add_info(chain->dev, ctrl, info);
@@ -2452,9 +2453,11 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
         */
        if (chain->dev->info->mappings) {
                bool custom = false;
-               unsigned int i;
 
-               for (i = 0; (mapping = chain->dev->info->mappings[i]); ++i) {
+               for (i = 0; chain->dev->info->mappings[i]; ++i) {
+                       const struct uvc_control_mapping *mapping =
+                               chain->dev->info->mappings[i];
+
                        if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
                            ctrl->info.selector == mapping->selector) {
                                __uvc_ctrl_add_mapping(chain, ctrl, mapping);
@@ -2467,10 +2470,9 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
        }
 
        /* Process common mappings next. */
-       mapping = uvc_ctrl_mappings;
-       mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings);
+       for (i = 0; i < ARRAY_SIZE(uvc_ctrl_mappings); ++i) {
+               const struct uvc_control_mapping *mapping = &uvc_ctrl_mappings[i];
 
-       for (; mapping < mend; ++mapping) {
                if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
                    ctrl->info.selector == mapping->selector)
                        __uvc_ctrl_add_mapping(chain, ctrl, mapping);
@@ -2478,14 +2480,16 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
 
        /* Finally process version-specific mappings. */
        if (chain->dev->uvc_version < 0x0150) {
-               mapping = uvc_ctrl_mappings_uvc11;
-               mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings_uvc11);
+               mappings = uvc_ctrl_mappings_uvc11;
+               num_mappings = ARRAY_SIZE(uvc_ctrl_mappings_uvc11);
        } else {
-               mapping = uvc_ctrl_mappings_uvc15;
-               mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings_uvc15);
+               mappings = uvc_ctrl_mappings_uvc15;
+               num_mappings = ARRAY_SIZE(uvc_ctrl_mappings_uvc15);
        }
 
-       for (; mapping < mend; ++mapping) {
+       for (i = 0; i < num_mappings; ++i) {
+               const struct uvc_control_mapping *mapping = &mappings[i];
+
                if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
                    ctrl->info.selector == mapping->selector)
                        __uvc_ctrl_add_mapping(chain, ctrl, mapping);