eal: fix multi-process hotplug if attached in secondary

Consider the following scenario:

 1) primary process (A) starts, probes the bus
 2) a secondary process (B) starts, probes the bus
 3) yet another secondary process (C) starts
 4) (C) registers the pci driver and hotplugs the device
    * an IPC attach req is sent to the primary (A)
      * (A) ignores the -EEXIST from process-local probe
      * (A) propagates the request to all secondary processes
        * (B) responds with -EEXIST
      * (A) replies to the original request with the -EEXIST
        return code
    * the -EEXIST is returned back to the user, although the
      device was successfully attached both locally and in
      all other processes

This patch makes the primary process reply with rc=0 even if
there was another secondary process with the device already
attached. The primary process already didn't reply with -EEXIST
when the device was attached locally, so now this behavior is
even more consistent. Looking by the code, this seems to be the
originally intended behavior.

Fixes: ac9e4a17370f ("eal: support attach/detach shared device from secondary")

Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>

diff --git a/lib/librte_eal/common/hotplug_mp.c b/lib/librte_eal/common/hotplug_mp.c
index d9e6790..ed0d7d3 100644 (file)
--- a/lib/librte_eal/common/hotplug_mp.c
+++ b/lib/librte_eal/common/hotplug_mp.c
@@ -404,13 +404,13 @@ int eal_dev_hotplug_request_to_secondary(struct eal_dev_mp_req *req)
                struct eal_dev_mp_req *resp =
                        (struct eal_dev_mp_req *)mp_reply.msgs[i].param;
                if (resp->result != 0) {
-                       req->result = resp->result;
                        if (req->t == EAL_DEV_REQ_TYPE_ATTACH &&
-                               req->result != -EEXIST)
-                               break;
+                               resp->result == -EEXIST)
+                               continue;
                        if (req->t == EAL_DEV_REQ_TYPE_DETACH &&
-                               req->result != -ENOENT)
-                               break;
+                               resp->result == -ENOENT)
+                               continue;
+                       req->result = resp->result;
                }
        }