[LU-5696] missing wakeup for ptlrpc_check_set

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.7.0
• Severity: 3
• Assignee: Liang Zhen (Inactive)
• Reporter: Liang Zhen (Inactive)

Description

Although very liketly, but there is no guarantee that request_out_callback will happen before reply_in_callback, if a request got reply before got request_out_callback(), then ptlrpc_unregister_reply() will return false because request has not been unlinked and req:;rq_req_unlink is not set to false.

static inline int                       
ptlrpc_client_recv_or_unlink(struct ptlrpc_request *req)
{               
        int rc;
                
        spin_lock(&req->rq_lock);          
        ......
        rc = req->rq_receiving_reply ;
        rc = rc || req->rq_req_unlink || req->rq_reply_unlink;
        spin_unlock(&req->rq_lock);
        return rc;
}         

After this, even request_in_callback() happened, there is no wakeup for this request, ptlrpcd or app thread will keep waiting.