linux-kernel - [PATCH net-next v4] net/tun: Call netdev notifiers

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Message-ID: <20201118054555.14248-1-ms@dev.tdt.de>
Date:   Wed, 18 Nov 2020 06:45:55 +0100
From:   Martin Schiller <ms@....tdt.de>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Martin Schiller <ms@....tdt.de>
Subject: [PATCH net-next v4] net/tun: Call netdev notifiers

Call netdev notifiers before and after changing the device type.

Signed-off-by: Martin Schiller <ms@....tdt.de>
---
Changes to v3:
* Handle return value of call_netdevice_notifiers()

Changes to v2:
* Use subject_prefix 'net-next' to fix 'fixes_present' issue

Changes to v1:
* Fix 'subject_prefix' and 'checkpatch' warnings

---
 drivers/net/tun.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 3d45d56172cb..704306695b88 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -3071,10 +3071,19 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 				   "Linktype set failed because interface is up\n");
 			ret = -EBUSY;
 		} else {
+			ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
+						       tun->dev);
+			ret = notifier_to_errno(err);
+			if (ret) {
+				netif_info(tun, drv, tun->dev,
+					   "Refused to change device type\n");
+				break;
+			}
 			tun->dev->type = (int) arg;
 			netif_info(tun, drv, tun->dev, "linktype set to %d\n",
 				   tun->dev->type);
-			ret = 0;
+			call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
+						 tun->dev);
 		}
 		break;
 
-- 
2.20.1