linux-kernel - [PATCH v2 4/7] media: v4l2-core: return -ENODEV from ioctl when not registered

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Date:   Thu, 10 Jun 2021 23:43:02 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     Arnd Bergmann <arnd@...db.de>,
        "Lad, Prabhakar" <prabhakar.csengg@...il.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Vaibhav Gupta <vaibhavgupta40@...il.com>,
        Liu Shixin <liushixin2@...wei.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-staging@...ts.linux.dev
Subject: [PATCH v2 4/7] media: v4l2-core: return -ENODEV from ioctl when not registered

From: Arnd Bergmann <arnd@...db.de>

I spotted a minor difference is handling of unregistered devices
between native and compat ioctls: the native handler never tries
to call into the driver if a device is not marked as registered.

I did not check whether this can cause issues in the kernel, or
just a different between return codes, but it clearly makes
sense that both should behave the same way.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 0ca75f6784c5..47aff3b19742 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -1244,6 +1244,9 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
 	if (!file->f_op->unlocked_ioctl)
 		return ret;
 
+	if (!video_is_registered(vdev))
+		return -ENODEV;
+
 	if (_IOC_TYPE(cmd) == 'V' && _IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
 		ret = file->f_op->unlocked_ioctl(file, cmd,
 					(unsigned long)compat_ptr(arg));
-- 
2.29.2