| Message ID | 20210928125500.167943-8-atenart@kernel.org (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Userspace spinning on net-sysfs access | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 8 maintainers not CCed: weiwan@google.com ap420073@gmail.com arnd@arndb.de bjorn@kernel.org memxor@gmail.com daniel@iogearbox.net edumazet@google.com alobakin@pm.me |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 6 this patch: 6 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 36 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 6 this patch: 6 |
| netdev/header_inline | success | Link |
diff --git a/net/core/dev.c b/net/core/dev.c index 02f9d505dbe2..a1eab120bb50 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10611,10 +10611,15 @@ void netdev_run_todo(void) if (dev->needs_free_netdev) free_netdev(dev); - /* Report a network device has been unregistered */ rtnl_lock(); + unlist_netdevice_name(dev); + synchronize_net(); + netdev_name_node_free(dev->name_node); + dev_net(dev)->dev_unreg_count--; __rtnl_unlock(); + + /* Report a network device has been unregistered */ wake_up(&netdev_unregistering_wq); /* Free network device */ @@ -11039,7 +11044,12 @@ void unregister_netdevice_many(struct list_head *head) list_for_each_entry(dev, head, unreg_list) { /* And unlink it from device chain. */ unlist_netdevice(dev); - unlist_netdevice_name(dev); + + /* Unreference the net device from the node name. From this + * point on the node name is only used for naming collision + * detection. + */ + dev->name_node->dev = NULL; dev->reg_state = NETREG_UNREGISTERING; } @@ -11072,7 +11082,6 @@ void unregister_netdevice_many(struct list_head *head) dev_mc_flush(dev); netdev_name_node_alt_flush(dev); - netdev_name_node_free(dev->name_node); if (dev->netdev_ops->ndo_uninit) dev->netdev_ops->ndo_uninit(dev);
Keep the node name collision detection working until the last registration stage, by delaying the removal of the name nodes in run_todo. This allows to perform unregistration operations being sensitive to name collisions, in run_todo. As run_todo has sections of code running without the rtnl lock taken, this will allow to perform some of those operations not under this lock (when possible). While we move the removal of the name node until a late unregistration stage, we still want to avoid returning a net device reference when it's being unregistered (calling __dev_get_by_name for example). We keep this logic by setting the node name dev reference to NULL. This follows the logic of __dev_get_by_name. Altnames are in the same list, they are not special here. From now on we have to be strict on the use of __dev_get_by_name vs netdev_name_node_lookup. One is designed to get the device, the other one to lookup in the list of currently reserved names. Current users should have been fixed by previous patches. One side effect is there is now a window between unregistering the netdevice and running the todo where names are still reserved and can't be used for new device creation. Signed-off-by: Antoine Tenart <atenart@kernel.org> --- net/core/dev.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)