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6ab0f86694
Once RTNL is replaced with rtnl_net_lock(), we need a mechanism to guarantee that rtnl_af_ops is alive during inflight RTM_SETLINK even when its module is being unloaded. Let's use SRCU to protect ops. rtnl_af_lookup() now iterates rtnl_af_ops under RCU and returns SRCU-protected ops pointer. The caller must call rtnl_af_put() to release the pointer after the use. Also, rtnl_af_unregister() unlinks the ops first and calls synchronize_srcu() to wait for inflight RTM_SETLINK requests to complete. Note that rtnl_af_ops needs to be protected by its dedicated lock when RTNL is removed. Note also that BUG_ON() in do_setlink() is changed to the normal error handling as a different af_ops might be found after validate_linkmsg(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>