Em Thu, 02 Nov 2017 04:51:40 +0200
Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> escreveu:
> Hi Mauro,
>
> Thank you for the patch.
>
> On Wednesday, 1 November 2017 23:05:45 EET Mauro Carvalho Chehab wrote:
> > Smatch reports this warning:
> > drivers/media/v4l2-core/v4l2-async.c:597 v4l2_async_register_subdev()
> > error: uninitialized symbol 'ret'.
> >
> > However, there's nothing wrong there. So, just shut up the
> > warning.
>
> Nothing wrong, really ? ret does seem to be used uninitialized when the
> function returns at the very last line.
There's nothing wrong. If you follow the logic, you'll see that
the line:
return ret;
is called only at "err_unbind" label, with is called only on
two places:
ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
if (ret)
goto err_unbind;
ret = v4l2_async_notifier_try_complete(notifier);
if (ret)
goto err_unbind;
There, ret is defined.
Yeah, the logic there is confusing.
Thanks,
Mauro
media: v4l2-async: shut up an unitialized symbol warning
Smatch reports this warning:
drivers/media/v4l2-core/v4l2-async.c:597 v4l2_async_register_subdev() error: uninitialized symbol 'ret'.
However, there's nothing wrong there. Yet, the logic is more
complex than it should. So, rework it to make clearer about
what happens when ret != 0.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-async.c | 38 +++++++++++++++--------------------
1 file changed, 17 insertions(+), 21 deletions(-)
--- patchwork.orig/drivers/media/v4l2-core/v4l2-async.c
+++ patchwork/drivers/media/v4l2-core/v4l2-async.c
@@ -532,7 +532,7 @@ int v4l2_async_register_subdev(struct v4
{
struct v4l2_async_notifier *subdev_notifier;
struct v4l2_async_notifier *notifier;
- int ret;
+ int ret = 0;
/*
* No reference taken. The reference is held by the device
@@ -560,11 +560,11 @@ int v4l2_async_register_subdev(struct v4
ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
if (ret)
- goto err_unbind;
+ break;
ret = v4l2_async_notifier_try_complete(notifier);
if (ret)
- goto err_unbind;
+ break;
goto out_unlock;
}
@@ -572,26 +572,22 @@ int v4l2_async_register_subdev(struct v4
/* None matched, wait for hot-plugging */
list_add(&sd->async_list, &subdev_list);
-out_unlock:
- mutex_unlock(&list_lock);
-
- return 0;
-
-err_unbind:
- /*
- * Complete failed. Unbind the sub-devices bound through registering
- * this async sub-device.
- */
- subdev_notifier = v4l2_async_find_subdev_notifier(sd);
- if (subdev_notifier)
- v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
-
- if (sd->asd)
- v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
- v4l2_async_cleanup(sd);
+ if (ret) {
+ /*
+ * Complete failed. Unbind the sub-devices bound through registering
+ * this async sub-device.
+ */
+ subdev_notifier = v4l2_async_find_subdev_notifier(sd);
+ if (subdev_notifier)
+ v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
+
+ if (sd->asd)
+ v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
+ v4l2_async_cleanup(sd);
+ }
+out_unlock:
mutex_unlock(&list_lock);
-
return ret;
}
EXPORT_SYMBOL(v4l2_async_register_subdev);
