ethdev: prevent duplicate event callback

This change prevents the attempt to add a structure which is
already on the callback list. If a struct with matching
parameters is found on the list, then no action is taken.

Fixes: ac2f69c ("ethdev: fix crash if malloc of user callback fails")

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Acked-by: Wenzhuo Lu <wenzhuo.lu@intel.com>

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 0d9d9c1..fde8112 100644 (file)
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -2449,14 +2449,15 @@ rte_eth_dev_callback_register(uint8_t port_id,
        }
 
        /* create a new callback. */
-       if (user_cb == NULL)
+       if (user_cb == NULL) {
                user_cb = rte_zmalloc("INTR_USER_CALLBACK",
                                        sizeof(struct rte_eth_dev_callback), 0);
-       if (user_cb != NULL) {
-               user_cb->cb_fn = cb_fn;
-               user_cb->cb_arg = cb_arg;
-               user_cb->event = event;
-               TAILQ_INSERT_TAIL(&(dev->link_intr_cbs), user_cb, next);
+               if (user_cb != NULL) {
+                       user_cb->cb_fn = cb_fn;
+                       user_cb->cb_arg = cb_arg;
+                       user_cb->event = event;
+                       TAILQ_INSERT_TAIL(&(dev->link_intr_cbs), user_cb, next);
+               }
        }
 
        rte_spinlock_unlock(&rte_eth_dev_cb_lock);