[PATCH v6 2/5] eal: mp: end the multiprocess thread during cleanup

[Stephen Hemminger]

When rte_eal_cleanup is called, all control threads should exit.
For the mp thread, this best handled by closing the mp_socket
and letting the thread see that.

This also fixes potential problems where the mp_socket gets
another hard error, and the thread runs away repeating itself
by reading the same error.

Fixes: 85d6815fa6d0 ("eal: close multi-process socket during cleanup")
Cc: qi.z.zh...@intel.com
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
Acked-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
 lib/eal/common/eal_common_proc.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/eal/common/eal_common_proc.c b/lib/eal/common/eal_common_proc.c
index ebd0f6673b8b..b33d58ea0a0f 100644
--- a/lib/eal/common/eal_common_proc.c
+++ b/lib/eal/common/eal_common_proc.c
@@ -282,8 +282,17 @@ read_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
        msgh.msg_control = control;
        msgh.msg_controllen = sizeof(control);
 
+retry:
        msglen = recvmsg(mp_fd, &msgh, 0);
+
+       /* zero length message means socket was closed */
+       if (msglen == 0)
+               return 0;
+
        if (msglen < 0) {
+               if (errno == EINTR)
+                       goto retry;
+
                RTE_LOG(ERR, EAL, "recvmsg failed, %s\n", strerror(errno));
                return -1;
        }
@@ -311,7 +320,7 @@ read_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
                RTE_LOG(ERR, EAL, "invalid received data length\n");
                return -1;
        }
-       return 0;
+       return msglen;
 }
 
 static void
@@ -385,8 +394,13 @@ mp_handle(void *arg __rte_unused)
        struct sockaddr_un sa;
 
        while (mp_fd >= 0) {
-               if (read_msg(&msg, &sa) == 0)
-                       process_msg(&msg, &sa);
+               int ret;
+
+               ret = read_msg(&msg, &sa);
+               if (ret <= 0)
+                       break;
+
+               process_msg(&msg, &sa);
        }
 
        return NULL;
-- 
2.30.2