[PATCH AUTOSEL 5.6 069/129] net: qualcomm: rmnet: Allow configuration updates to existing devices

Sasha Levin
2020-04-15T11:41:49Z

From: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

[ Upstream commit 2abb5792387eb188b12051337d5dcd2cba615cb0 ]

This allows the changelink operation to succeed if the mux_id was
specified as an argument. Note that the mux_id must match the
existing mux_id of the rmnet device or should be an unused mux_id.

Fixes: 1dc49e9d164c ("net: rmnet: do not allow to change mux id if mux id is duplicated")
Reported-and-tested-by: Alex Elder <elder@linaro.org>
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../ethernet/qualcomm/rmnet/rmnet_config.c | 31 ++++++++++++-------
1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
index fbf4cbcf1a654..02cdbb22d3355 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
@@ -279,7 +279,6 @@ static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],
{
struct rmnet_priv *priv = netdev_priv(dev);
struct net_device *real_dev;
- struct rmnet_endpoint *ep;
struct rmnet_port *port;
u16 mux_id;

@@ -294,19 +293,27 @@ static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],

if (data[IFLA_RMNET_MUX_ID]) {
mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
- if (rmnet_get_endpoint(port, mux_id)) {
- NL_SET_ERR_MSG_MOD(extack, "MUX ID already exists");
- return -EINVAL;
- }
- ep = rmnet_get_endpoint(port, priv->mux_id);
- if (!ep)
- return -ENODEV;

- hlist_del_init_rcu(&ep->hlnode);
- hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
+ if (mux_id != priv->mux_id) {
+ struct rmnet_endpoint *ep;
+
+ ep = rmnet_get_endpoint(port, priv->mux_id);
+ if (!ep)
+ return -ENODEV;

- ep->mux_id = mux_id;
- priv->mux_id = mux_id;
+ if (rmnet_get_endpoint(port, mux_id)) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "MUX ID already exists");
+ return -EINVAL;
+ }
+
+ hlist_del_init_rcu(&ep->hlnode);
+ hlist_add_head_rcu(&ep->hlnode,
+ &port->muxed_ep[mux_id]);
+
+ ep->mux_id = mux_id;
+ priv->mux_id = mux_id;
+ }
}

if (data[IFLA_RMNET_FLAGS]) {
--
2.20.1