I'm so sorry I missed the last emails for this discussion.Thank you for your effort!
Yes, commit (86434744) is the trigger of the problem described in
https://lore.kernel.org/linux-s390/45a19f8b-1b64-3459-c28c-aebab4fd8f1e@xxxxxxxxxxxxxxxxx/#t .
And I have tested just remove the following lines from smc_connection() can solve the above problem.
if (smc->use_fallback)
goto out;
I aggree that partly reverting the commit (86434744) is a better solution.
Thanks,
Guangguan Wang