net/tap: check ioctl on restore

[ upstream commit 8f3ca7f ]

After restoring the remote states, the return value of ioctl() is not
checked. Therefore, users cannot know whether the remote state is
restored successfully.

This patch add log for restoring failure.

Fixes: 4810d3a ("net/tap: restore state of remote device when closing")

Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

drivers/net/tap/rte_eth_tap.c

@@ -1133,8 +1133,11 @@ tap_dev_close(struct rte_eth_dev *dev)
 
 	if (internals->remote_if_index) {
 		/* Restore initial remote state */
-		ioctl(internals->ioctl_sock, SIOCSIFFLAGS,
+		int ret = ioctl(internals->ioctl_sock, SIOCSIFFLAGS,
 				&internals->remote_initial_flags);
+		if (ret)
+			TAP_LOG(ERR, "restore remote state failed: %d", ret);
+
 	}
 
 	rte_mempool_free(internals->gso_ctx_mp);