[dpdk-dev] [PATCH v4 3/8] distributor: do not use oldpkt when not needed

[Lukasz Wojciechowski]

rte_distributor_request_pkt and rte_distributor_get_pkt dereferenced
oldpkt parameter when in RTE_DIST_ALG_SINGLE even if number
of returned buffers from worker to distributor was 0.

This patch passes NULL to the legacy API when number of returned
buffers is 0. This allows passing NULL as oldpkt parameter.

Distribor tests were also updated passing NULL as oldpkt and
0 as number of returned packets, where packets are not returned.

Fixes: 775003ad2f96 ("distributor: add new burst-capable library")
Cc: david.hunt at intel.com
Cc: stable at dpdk.org

Signed-off-by: Lukasz Wojciechowski <l.wojciechow at partner.samsung.com>
---
 app/test/test_distributor.c              | 28 +++++++++---------------
 lib/librte_distributor/rte_distributor.c |  4 ++--
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/app/test/test_distributor.c b/app/test/test_distributor.c
index 0e49e3714..0e3ab0c4f 100644
--- a/app/test/test_distributor.c
+++ b/app/test/test_distributor.c
@@ -65,13 +65,10 @@ handle_work(void *arg)
 	struct rte_mbuf *buf[8] __rte_cache_aligned;
 	struct worker_params *wp = arg;
 	struct rte_distributor *db = wp->dist;
-	unsigned int count = 0, num = 0;
+	unsigned int count = 0, num;
 	unsigned int id = __atomic_fetch_add(&worker_idx, 1, __ATOMIC_RELAXED);
-	int i;
 
-	for (i = 0; i < 8; i++)
-		buf[i] = NULL;
-	num = rte_distributor_get_pkt(db, id, buf, buf, num);
+	num = rte_distributor_get_pkt(db, id, buf, NULL, 0);
 	while (!quit) {
 		__atomic_fetch_add(&worker_stats[id].handled_packets, num,
 				__ATOMIC_ACQ_REL);
@@ -279,20 +276,17 @@ handle_work_with_free_mbufs(void *arg)
 	struct rte_distributor *d = wp->dist;
 	unsigned int count = 0;
 	unsigned int i;
-	unsigned int num = 0;
+	unsigned int num;
 	unsigned int id = __atomic_fetch_add(&worker_idx, 1, __ATOMIC_RELAXED);
 
-	for (i = 0; i < 8; i++)
-		buf[i] = NULL;
-	num = rte_distributor_get_pkt(d, id, buf, buf, num);
+	num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 	while (!quit) {
 		count += num;
 		__atomic_fetch_add(&worker_stats[id].handled_packets, num,
 				__ATOMIC_ACQ_REL);
 		for (i = 0; i < num; i++)
 			rte_pktmbuf_free(buf[i]);
-		num = rte_distributor_get_pkt(d,
-				id, buf, buf, num);
+		num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 	}
 	count += num;
 	__atomic_fetch_add(&worker_stats[id].handled_packets, num,
@@ -351,7 +345,7 @@ handle_work_for_shutdown_test(void *arg)
 	struct worker_params *wp = arg;
 	struct rte_distributor *d = wp->dist;
 	unsigned int count = 0;
-	unsigned int num = 0;
+	unsigned int num;
 	unsigned int total = 0;
 	unsigned int i;
 	unsigned int returned = 0;
@@ -359,7 +353,7 @@ handle_work_for_shutdown_test(void *arg)
 	const unsigned int id = __atomic_fetch_add(&worker_idx, 1,
 			__ATOMIC_RELAXED);
 
-	num = rte_distributor_get_pkt(d, id, buf, buf, num);
+	num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 
 	zero_id = __atomic_load_n(&zero_idx, __ATOMIC_ACQUIRE);
 	if (id == zero_id && num > 0) {
@@ -376,8 +370,7 @@ handle_work_for_shutdown_test(void *arg)
 				__ATOMIC_ACQ_REL);
 		for (i = 0; i < num; i++)
 			rte_pktmbuf_free(buf[i]);
-		num = rte_distributor_get_pkt(d,
-				id, buf, buf, num);
+		num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 
 		zero_id = __atomic_load_n(&zero_idx, __ATOMIC_ACQUIRE);
 		if (id == zero_id && num > 0) {
@@ -400,13 +393,12 @@ handle_work_for_shutdown_test(void *arg)
 		while (zero_quit)
 			usleep(100);
 
-		num = rte_distributor_get_pkt(d,
-				id, buf, buf, num);
+		num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 
 		while (!quit) {
 			count += num;
 			rte_pktmbuf_free(pkt);
-			num = rte_distributor_get_pkt(d, id, buf, buf, num);
+			num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 			__atomic_fetch_add(&worker_stats[id].handled_packets,
 					num, __ATOMIC_ACQ_REL);
 		}
diff --git a/lib/librte_distributor/rte_distributor.c b/lib/librte_distributor/rte_distributor.c
index 1c047f065..8a12bf856 100644
--- a/lib/librte_distributor/rte_distributor.c
+++ b/lib/librte_distributor/rte_distributor.c
@@ -42,7 +42,7 @@ rte_distributor_request_pkt(struct rte_distributor *d,
 
 	if (unlikely(d->alg_type == RTE_DIST_ALG_SINGLE)) {
 		rte_distributor_request_pkt_single(d->d_single,
-			worker_id, oldpkt[0]);
+			worker_id, count ? oldpkt[0] : NULL);
 		return;
 	}
 
@@ -134,7 +134,7 @@ rte_distributor_get_pkt(struct rte_distributor *d,
 	if (unlikely(d->alg_type == RTE_DIST_ALG_SINGLE)) {
 		if (return_count <= 1) {
 			pkts[0] = rte_distributor_get_pkt_single(d->d_single,
-				worker_id, oldpkt[0]);
+				worker_id, return_count ? oldpkt[0] : NULL);
 			return (pkts[0]) ? 1 : 0;
 		} else
 			return -EINVAL;
-- 
2.17.1