Callbacks for mempool events were registered in a process-shared tailq.
This was inherently incorrect because the same function
may be loaded to a different address in each process.
Make the tailq process-private.
Use the EAL tailq lock to reduce the number of different locks
this module operates.

Fixes: da2b9cb25e5f ("mempool: add event callbacks")
Cc: sta...@dpdk.org

Signed-off-by: Dmitry Kozlyuk <dkozl...@nvidia.com>
---
 lib/mempool/rte_mempool.c | 54 ++++++++++-----------------------------
 lib/mempool/rte_mempool.h |  2 ++
 2 files changed, 16 insertions(+), 40 deletions(-)

diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
index de59009baf..1e039f6247 100644
--- a/lib/mempool/rte_mempool.c
+++ b/lib/mempool/rte_mempool.c
@@ -36,12 +36,10 @@ static struct rte_tailq_elem rte_mempool_tailq = {
 };
 EAL_REGISTER_TAILQ(rte_mempool_tailq)
 
-TAILQ_HEAD(mempool_callback_list, rte_tailq_entry);
+TAILQ_HEAD(mempool_callback_tailq, mempool_callback_data);
 
-static struct rte_tailq_elem callback_tailq = {
-       .name = "RTE_MEMPOOL_CALLBACK",
-};
-EAL_REGISTER_TAILQ(callback_tailq)
+static struct mempool_callback_tailq callback_tailq =
+               TAILQ_HEAD_INITIALIZER(callback_tailq);
 
 /* Invoke all registered mempool event callbacks. */
 static void
@@ -1372,6 +1370,7 @@ void rte_mempool_walk(void (*func)(struct rte_mempool *, 
void *),
 }
 
 struct mempool_callback_data {
+       TAILQ_ENTRY(mempool_callback_data) callbacks;
        rte_mempool_event_callback *func;
        void *user_data;
 };
@@ -1380,14 +1379,11 @@ static void
 mempool_event_callback_invoke(enum rte_mempool_event event,
                              struct rte_mempool *mp)
 {
-       struct mempool_callback_list *list;
-       struct rte_tailq_entry *te;
+       struct mempool_callback_data *cb;
        void *tmp_te;
 
        rte_mcfg_tailq_read_lock();
-       list = RTE_TAILQ_CAST(callback_tailq.head, mempool_callback_list);
-       RTE_TAILQ_FOREACH_SAFE(te, list, next, tmp_te) {
-               struct mempool_callback_data *cb = te->data;
+       RTE_TAILQ_FOREACH_SAFE(cb, &callback_tailq, callbacks, tmp_te) {
                rte_mcfg_tailq_read_unlock();
                cb->func(event, mp, cb->user_data);
                rte_mcfg_tailq_read_lock();
@@ -1399,10 +1395,7 @@ int
 rte_mempool_event_callback_register(rte_mempool_event_callback *func,
                                    void *user_data)
 {
-       struct mempool_callback_list *list;
-       struct rte_tailq_entry *te = NULL;
        struct mempool_callback_data *cb;
-       void *tmp_te;
        int ret;
 
        if (func == NULL) {
@@ -1411,36 +1404,23 @@ 
rte_mempool_event_callback_register(rte_mempool_event_callback *func,
        }
 
        rte_mcfg_tailq_write_lock();
-       list = RTE_TAILQ_CAST(callback_tailq.head, mempool_callback_list);
-       RTE_TAILQ_FOREACH_SAFE(te, list, next, tmp_te) {
-               cb = te->data;
+       TAILQ_FOREACH(cb, &callback_tailq, callbacks) {
                if (cb->func == func && cb->user_data == user_data) {
                        ret = -EEXIST;
                        goto exit;
                }
        }
 
-       te = rte_zmalloc("mempool_cb_tail_entry", sizeof(*te), 0);
-       if (te == NULL) {
-               RTE_LOG(ERR, MEMPOOL,
-                       "Cannot allocate event callback tailq entry!\n");
-               ret = -ENOMEM;
-               goto exit;
-       }
-
-       cb = rte_malloc("mempool_cb_data", sizeof(*cb), 0);
+       cb = calloc(1, sizeof(*cb));
        if (cb == NULL) {
-               RTE_LOG(ERR, MEMPOOL,
-                       "Cannot allocate event callback!\n");
-               rte_free(te);
+               RTE_LOG(ERR, MEMPOOL, "Cannot allocate event callback!\n");
                ret = -ENOMEM;
                goto exit;
        }
 
        cb->func = func;
        cb->user_data = user_data;
-       te->data = cb;
-       TAILQ_INSERT_TAIL(list, te, next);
+       TAILQ_INSERT_TAIL(&callback_tailq, cb, callbacks);
        ret = 0;
 
 exit:
@@ -1453,27 +1433,21 @@ int
 rte_mempool_event_callback_unregister(rte_mempool_event_callback *func,
                                      void *user_data)
 {
-       struct mempool_callback_list *list;
-       struct rte_tailq_entry *te = NULL;
        struct mempool_callback_data *cb;
        int ret = -ENOENT;
 
        rte_mcfg_tailq_write_lock();
-       list = RTE_TAILQ_CAST(callback_tailq.head, mempool_callback_list);
-       TAILQ_FOREACH(te, list, next) {
-               cb = te->data;
+       TAILQ_FOREACH(cb, &callback_tailq, callbacks) {
                if (cb->func == func && cb->user_data == user_data) {
-                       TAILQ_REMOVE(list, te, next);
+                       TAILQ_REMOVE(&callback_tailq, cb, callbacks);
                        ret = 0;
                        break;
                }
        }
        rte_mcfg_tailq_write_unlock();
 
-       if (ret == 0) {
-               rte_free(te);
-               rte_free(cb);
-       }
+       if (ret == 0)
+               free(cb);
        rte_errno = -ret;
        return ret;
 }
diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
index 3ada37cb86..bfc1f3c823 100644
--- a/lib/mempool/rte_mempool.h
+++ b/lib/mempool/rte_mempool.h
@@ -1847,6 +1847,8 @@ typedef void (rte_mempool_event_callback)(
  * Register a callback function invoked on mempool life cycle event.
  * The function will be invoked in the process
  * that performs an action which triggers the callback.
+ * Registration is process-private,
+ * i.e. each process must manage callbacks on its own if needed.
  *
  * @param func
  *   Callback function.
-- 
2.25.1

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