On Tue, May 10, 2022 at 08:58:38PM +0800, Guangguan Wang wrote: > > > On 2022/5/10 17:30, Tony Lu wrote: > > On Mon, May 09, 2022 at 07:58:37PM +0800, Guangguan Wang wrote: > >> Connect with O_NONBLOCK will not be completed immediately > >> and returns -EINPROGRESS. It is possible to use selector/poll > >> for completion by selecting the socket for writing. After select > >> indicates writability, a second connect function call will return > >> 0 to indicate connected successfully as TCP does, but smc returns > > > > If the connection is established successfully, the following up call of > > connect() returns -EISCONN (SS_CONNECTED), which is expected and SMC > > does it, same as TCP. > > > > In case of misunderstanding, could you append more detailed information? > > > > Thanks, > > Tony Lu > > > > io_uring uses nonblocking connect as follow steps: > 1) call connect with nonblocking > 2) wait for selector/poll to indicate writability > 3) call connect to confirm connection's state > > In the third step, tcp changes the socket state from SS_CONNECTING to > SS_CONNECTED and returns 0 if the connection is established successfully, > but smc returns -EISCONN. Based on the steps you list, I am wondering if it is finished in the step #1, the call of connect() in step #3 would return -EISCONN. Should we check 0 and -EISCONN in step #3? To fix this issue, I think we should be careful about adding and handling sock state, maybe we could push it to net-next and take advantage of sock state. And I will test this patch later in our test cases. Thanks, Tony Lu
