Re: [PATCH net 4/4] net/smc: Fix wq mismatch issue caused by smc fallback

On 27/10/2021 10:52, Tony Lu wrote:

From: Wen Gu <guwen@linux.alibaba.com>

A socket_wq mismatch issue may occur because of fallback.

When use SMC to replace TCP, applications add an epoll entry into SMC
socket's wq, but kernel uses clcsock's wq instead of SMC socket's wq
once fallback occurs, which means the application's epoll fd dosen't
work anymore.

For example:
server: nginx -g 'daemon off;'

client: smc_run wrk -c 1 -t 1 -d 5 http://11.200.15.93/index.html

  Running 5s test @ http://11.200.15.93/index.html
    1 threads and 1 connections
    Thread Stats   Avg      Stdev     Max   +/- Stdev
      Latency     0.00us    0.00us   0.00us    -nan%
      Req/Sec     0.00      0.00     0.00      -nan%
    0 requests in 5.00s, 0.00B read
  Requests/sec:      0.00
  Transfer/sec:       0.00B

This patch fixes this issue by using clcsock's wq regardless of
whether fallback occurs.

I need to spend some more time testing and thinking about this fix.
Thank you.