devlink: protect devlink->dev by the instance lock

devlink->dev is assumed to be always valid as long as any
outstanding reference to the devlink instance exists.

In prep for weakening of the references take the instance lock.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/devlink/devl_internal.h b/net/devlink/devl_internal.h
index 14767e8..6342552 100644 (file)
--- a/net/devlink/devl_internal.h
+++ b/net/devlink/devl_internal.h
@@ -131,7 +131,8 @@ struct devlink_gen_cmd {
 
 extern const struct genl_small_ops devlink_nl_ops[56];
 
-struct devlink *devlink_get_from_attrs(struct net *net, struct nlattr **attrs);
+struct devlink *
+devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs);
 
 void devlink_notify_unregister(struct devlink *devlink);
 void devlink_notify_register(struct devlink *devlink);

diff --git a/net/devlink/leftover.c b/net/devlink/leftover.c
index e6d6c7f..bec408d 100644 (file)
--- a/net/devlink/leftover.c
+++ b/net/devlink/leftover.c
@@ -6314,12 +6314,10 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 
        start_offset = state->start_offset;
 
-       devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);
+       devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
        if (IS_ERR(devlink))
                return PTR_ERR(devlink);
 
-       devl_lock(devlink);
-
        if (!attrs[DEVLINK_ATTR_REGION_NAME]) {
                NL_SET_ERR_MSG(cb->extack, "No region name provided");
                err = -EINVAL;
@@ -7735,9 +7733,10 @@ devlink_health_reporter_get_from_cb(struct netlink_callback *cb)
        struct nlattr **attrs = info->attrs;
        struct devlink *devlink;
 
-       devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);
+       devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
        if (IS_ERR(devlink))
                return NULL;
+       devl_unlock(devlink);
 
        reporter = devlink_health_reporter_get_from_attrs(devlink, attrs);
        devlink_put(devlink);

diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c
index a552e72..6911174 100644 (file)
--- a/net/devlink/netlink.c
+++ b/net/devlink/netlink.c
@@ -82,7 +82,8 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
        [DEVLINK_ATTR_REGION_DIRECT] = { .type = NLA_FLAG },
 };
 
-struct devlink *devlink_get_from_attrs(struct net *net, struct nlattr **attrs)
+struct devlink *
+devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs)
 {
        struct devlink *devlink;
        unsigned long index;
@@ -96,9 +97,11 @@ struct devlink *devlink_get_from_attrs(struct net *net, struct nlattr **attrs)
        devname = nla_data(attrs[DEVLINK_ATTR_DEV_NAME]);
 
        devlinks_xa_for_each_registered_get(net, index, devlink) {
+               devl_lock(devlink);
                if (strcmp(devlink->dev->bus->name, busname) == 0 &&
                    strcmp(dev_name(devlink->dev), devname) == 0)
                        return devlink;
+               devl_unlock(devlink);
                devlink_put(devlink);
        }
 
@@ -113,10 +116,10 @@ static int devlink_nl_pre_doit(const struct genl_split_ops *ops,
        struct devlink *devlink;
        int err;
 
-       devlink = devlink_get_from_attrs(genl_info_net(info), info->attrs);
+       devlink = devlink_get_from_attrs_lock(genl_info_net(info), info->attrs);
        if (IS_ERR(devlink))
                return PTR_ERR(devlink);
-       devl_lock(devlink);
+
        info->user_ptr[0] = devlink;
        if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_PORT) {
                devlink_port = devlink_port_get_from_info(devlink, info);