[dpdk-dev] [PATCH v2] eal: don't fail secondary if primary is missing tailqs

[Jean Tourrilhes]

If the primary and secondary process were build using different build
systems, the list of constructors included by the linker in each
binary might be different. Tailqs are registered via constructors, so
the linker magic will directly impact which tailqs are registered with
the primary and the secondary.

DPDK currently assumes that the secondary has a subset of the tailqs
registered at the primary. In some build scenario, the secondary might
register a tailq that the primary did not register. In this case,
instead of exiting with a panic, just unregister the offending tailq
and allow the secondary to run.

Signed-off-by: Jean Tourrilhes <jt at labs.hpe.com>
---
 lib/librte_eal/common/eal_common_tailqs.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_tailqs.c 
b/lib/librte_eal/common/eal_common_tailqs.c
index bb08ec8..cf5a771 100644
--- a/lib/librte_eal/common/eal_common_tailqs.c
+++ b/lib/librte_eal/common/eal_common_tailqs.c
@@ -143,6 +143,8 @@ rte_eal_tailq_update(struct rte_tailq_elem *t)
                t->head = rte_eal_tailq_create(t->name);
        } else {
                t->head = rte_eal_tailq_lookup(t->name);
+               if (t->head != NULL)
+                       rte_tailqs_count++;
        }
 }

@@ -178,19 +180,27 @@ int
 rte_eal_tailqs_init(void)
 {
        struct rte_tailq_elem *t;
+       void *tmp_te;

        rte_tailqs_count = 0;

-       TAILQ_FOREACH(t, &rte_tailq_elem_head, next) {
+       TAILQ_FOREACH_SAFE(t, &rte_tailq_elem_head, next, tmp_te) {
                /* second part of register job for "early" tailqs, see
                 * rte_eal_tailq_register and EAL_REGISTER_TAILQ */
                rte_eal_tailq_update(t);
                if (t->head == NULL) {
                        RTE_LOG(ERR, EAL,
                                "Cannot initialize tailq: %s\n", t->name);
-                       /* no need to TAILQ_REMOVE, we are going to panic in
-                        * rte_eal_init() */
-                       goto fail;
+                       if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+                               /* no need to TAILQ_REMOVE, we are going
+                                * to panic in rte_eal_init() */
+                               goto fail;
+                       } else {
+                               /* This means our list of constructor is
+                                * no the same as primary. Just remove
+                                * that missing tailq and continue */
+                               TAILQ_REMOVE(&rte_tailq_elem_head, t, next);
+                       }
                }
        }