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Subject[PATCH 03/20] media: usb: uvc_ctrl.c: add temp variable for list iteration
Date
From: "Daniel W. S. Almeida" <dwlsalmeida@gmail.com>

Fixes the following coccinelle report:

drivers/media/usb/uvc/uvc_ctrl.c:1860:5-11:
ERROR: invalid reference to the index variable of the iterator on line 1854

By introducing a temporary variable to iterate the list.

Do not dereference the 'entity' pointer if it is not found in the list.

Found using - Coccinelle (http://coccinelle.lip6.fr)

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
---
drivers/media/usb/uvc/uvc_ctrl.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index e399b9fad757..567bdedc2ff2 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1842,7 +1842,8 @@ static int uvc_ctrl_init_xu_ctrl(struct uvc_device *dev,
int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
struct uvc_xu_control_query *xqry)
{
- struct uvc_entity *entity;
+ struct uvc_entity *entity = NULL;
+ struct uvc_entity *cursor = NULL;
struct uvc_control *ctrl;
unsigned int i, found = 0;
u32 reqflags;
@@ -1851,13 +1852,15 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
int ret;

/* Find the extension unit. */
- list_for_each_entry(entity, &chain->entities, chain) {
- if (UVC_ENTITY_TYPE(entity) == UVC_VC_EXTENSION_UNIT &&
- entity->id == xqry->unit)
+ list_for_each_entry(cursor, &chain->entities, chain) {
+ if (UVC_ENTITY_TYPE(cursor) == UVC_VC_EXTENSION_UNIT &&
+ cursor->id == xqry->unit) {
+ entity = cursor;
break;
+ }
}

- if (entity->id != xqry->unit) {
+ if (!entity || entity->id != xqry->unit) {
uvc_trace(UVC_TRACE_CONTROL, "Extension unit %u not found.\n",
xqry->unit);
return -ENOENT;
--
2.28.0
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