[PATCH 4.19 12/91] net: Have netpoll bring-up DSA management interface

Greg Kroah-Hartman
2020-11-23T12:30:19Z

From: Florian Fainelli <f.fainelli@gmail.com>

[ Upstream commit 1532b9778478577152201adbafa7738b1e844868 ]

DSA network devices rely on having their DSA management interface up and
running otherwise their ndo_open() will return -ENETDOWN. Without doing
this it would not be possible to use DSA devices as netconsole when
configured on the command line. These devices also do not utilize the
upper/lower linking so the check about the netpoll device having upper
is not going to be a problem.

The solution adopted here is identical to the one done for
net/ipv4/ipconfig.c with 728c02089a0e ("net: ipv4: handle DSA enabled
master network devices"), with the network namespace scope being
restricted to that of the process configuring netpoll.

Fixes: 04ff53f96a93 ("net: dsa: Add netconsole support")
Tested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20201117035236.22658-1-f.fainelli@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/netpoll.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)

--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -28,6 +28,7 @@
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/if_vlan.h>
+#include <net/dsa.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/addrconf.h>
@@ -638,15 +639,15 @@ EXPORT_SYMBOL_GPL(__netpoll_setup);

int netpoll_setup(struct netpoll *np)
{
- struct net_device *ndev = NULL;
+ struct net_device *ndev = NULL, *dev = NULL;
+ struct net *net = current->nsproxy->net_ns;
struct in_device *in_dev;
int err;

rtnl_lock();
- if (np->dev_name[0]) {
- struct net *net = current->nsproxy->net_ns;
+ if (np->dev_name[0])
ndev = __dev_get_by_name(net, np->dev_name);
- }
+
if (!ndev) {
np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
err = -ENODEV;
@@ -654,6 +655,19 @@ int netpoll_setup(struct netpoll *np)
}
dev_hold(ndev);

+ /* bring up DSA management network devices up first */
+ for_each_netdev(net, dev) {
+ if (!netdev_uses_dsa(dev))
+ continue;
+
+ err = dev_change_flags(dev, dev->flags | IFF_UP);
+ if (err < 0) {
+ np_err(np, "%s failed to open %s\n",
+ np->dev_name, dev->name);
+ goto put;
+ }
+ }
+
if (netdev_master_upper_dev_get(ndev)) {
np_err(np, "%s is a slave device, aborting\n", np->dev_name);
err = -EBUSY;