net: devlink: add port type spinlock

Add spinlock to protect port type and type_dev pointer consistency.
Without that, userspace may see inconsistent type and type_dev
combinations.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
v1->v2:
- rebased
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 63de99e09f046e9bc91f9b77aab0051d8919f943..cb9b060033e1d660be0578d5b0fbdd865f63eca7 100644 (file)
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -16,6 +16,7 @@
 #include <linux/gfp.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
+#include <linux/spinlock.h>
 #include <net/net_namespace.h>
 #include <uapi/linux/devlink.h>
 
@@ -53,6 +54,9 @@ struct devlink_port {
        struct devlink *devlink;
        unsigned index;
        bool registered;
+       spinlock_t type_lock; /* Protects type and type_dev
+                              * pointer consistency.
+                              */
        enum devlink_port_type type;
        enum devlink_port_type desired_type;
        void *type_dev;

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 860ab3a721e07f3a660667c8c71ee080d972c71f..19fa5be28127cb668f9c4cf2dcd340ee3e1ffba0 100644 (file)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -19,6 +19,7 @@
 #include <linux/device.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
+#include <linux/spinlock.h>
 #include <rdma/ib_verbs.h>
 #include <net/netlink.h>
 #include <net/genetlink.h>
@@ -543,12 +544,14 @@ static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink,
                goto nla_put_failure;
        if (nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX, devlink_port->index))
                goto nla_put_failure;
+
+       spin_lock(&devlink_port->type_lock);
        if (nla_put_u16(msg, DEVLINK_ATTR_PORT_TYPE, devlink_port->type))
-               goto nla_put_failure;
+               goto nla_put_failure_type_locked;
        if (devlink_port->desired_type != DEVLINK_PORT_TYPE_NOTSET &&
            nla_put_u16(msg, DEVLINK_ATTR_PORT_DESIRED_TYPE,
                        devlink_port->desired_type))
-               goto nla_put_failure;
+               goto nla_put_failure_type_locked;
        if (devlink_port->type == DEVLINK_PORT_TYPE_ETH) {
                struct net_device *netdev = devlink_port->type_dev;
 
@@ -557,7 +560,7 @@ static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink,
                                 netdev->ifindex) ||
                     nla_put_string(msg, DEVLINK_ATTR_PORT_NETDEV_NAME,
                                    netdev->name)))
-                       goto nla_put_failure;
+                       goto nla_put_failure_type_locked;
        }
        if (devlink_port->type == DEVLINK_PORT_TYPE_IB) {
                struct ib_device *ibdev = devlink_port->type_dev;
@@ -565,14 +568,17 @@ static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink,
                if (ibdev &&
                    nla_put_string(msg, DEVLINK_ATTR_PORT_IBDEV_NAME,
                                   ibdev->name))
-                       goto nla_put_failure;
+                       goto nla_put_failure_type_locked;
        }
+       spin_unlock(&devlink_port->type_lock);
        if (devlink_nl_port_attrs_put(msg, devlink_port))
                goto nla_put_failure;
 
        genlmsg_end(msg, hdr);
        return 0;
 
+nla_put_failure_type_locked:
+       spin_unlock(&devlink_port->type_lock);
 nla_put_failure:
        genlmsg_cancel(msg, hdr);
        return -EMSGSIZE;
@@ -5300,6 +5306,7 @@ int devlink_port_register(struct devlink *devlink,
        devlink_port->devlink = devlink;
        devlink_port->index = port_index;
        devlink_port->registered = true;
+       spin_lock_init(&devlink_port->type_lock);
        list_add_tail(&devlink_port->list, &devlink->port_list);
        INIT_LIST_HEAD(&devlink_port->param_list);
        mutex_unlock(&devlink->lock);
@@ -5330,8 +5337,10 @@ static void __devlink_port_type_set(struct devlink_port *devlink_port,
 {
        if (WARN_ON(!devlink_port->registered))
                return;
+       spin_lock(&devlink_port->type_lock);
        devlink_port->type = type;
        devlink_port->type_dev = type_dev;
+       spin_unlock(&devlink_port->type_lock);
        devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
 }