if_vxlan(4): Stop invoking vxlan_stop event handler when the interface was not configured

[zlei]

Summary

It is harmless but pointless to invoke vxlan_stop event handler when the interface was not previously configured. This change will also prevent an assert panic from t4_vxlan_stop_handler().

[kib]

Since eventhandlers are called outside the vxlan_sx protection, it is not even guaranteed that the stop event comes after the start, or that events are properly interleaved. In other words, drivers must be prepared for the situation like 'stop without start' or 'two stops after one start'.

sys/net/if_vxlan.c

1824

[zlei]

Address @kib 's comment.

[zlei]

In D48494#1106769, @kib wrote:

Since eventhandlers are called outside the vxlan_sx protection, it is not even guaranteed that the stop event comes after the start, or that events are properly interleaved. In other words, drivers must be prepared for the situation like 'stop without start' or 'two stops after one start'.

Emm, I read the code carefully, both vxlan_start and vxlan_event handlers are called within protection of vxlan_sx. So drivers will get proper event order. Am I missing something important ?

[kib]

In D48494#1106867, @zlei wrote:

In D48494#1106769, @kib wrote:

Since eventhandlers are called outside the vxlan_sx protection, it is not even guaranteed that the stop event comes after the start, or that events are properly interleaved. In other words, drivers must be prepared for the situation like 'stop without start' or 'two stops after one start'.

Emm, I read the code carefully, both vxlan_start and vxlan_event handlers are called within protection of vxlan_sx. So drivers will get proper event order. Am I missing something important ?

Oh, I did not noticed the global sx (vxlan_sx).