[PATCH] pipeline: fix packet mirroring configuration

[Cristian Dumitrescu <cristian.dumitrescu@intel.com>]

Fix segmentation fault due to null pointer dereferencing inside the
"mirror" instruction when number of mirroring slots is set to 0. This
was taking place when the "mirror" instruction was used without the
mirror feature being properly configured, i.e. the API function
rte_swx_pipeline_mirroring_config was not called at initialization.

Fixes: dac0ecd9098 (" pipeline: support packet mirroring")

Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
---
 lib/pipeline/rte_swx_pipeline.c |  5 ++---
 lib/pipeline/rte_swx_pipeline.h | 10 ++++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/lib/pipeline/rte_swx_pipeline.c b/lib/pipeline/rte_swx_pipeline.c
index 659d8726d1..066356684e 100644
--- a/lib/pipeline/rte_swx_pipeline.c
+++ b/lib/pipeline/rte_swx_pipeline.c
@@ -612,9 +612,6 @@ mirroring_build(struct rte_swx_pipeline *p)
 {
 	uint32_t i;
 
-	if (!p->n_mirroring_slots || !p->n_mirroring_sessions)
-		return 0;
-
 	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
 		struct thread *t = &p->threads[i];
 
@@ -9772,6 +9769,8 @@ rte_swx_pipeline_config(struct rte_swx_pipeline **p, int numa_node)
 	TAILQ_INIT(&pipeline->metarrays);
 
 	pipeline->n_structs = 1; /* Struct 0 is reserved for action_data. */
+	pipeline->n_mirroring_slots = RTE_SWX_PACKET_MIRRORING_SLOTS_DEFAULT;
+	pipeline->n_mirroring_sessions = RTE_SWX_PACKET_MIRRORING_SESSIONS_DEFAULT;
 	pipeline->numa_node = numa_node;
 
 	status = port_in_types_register(pipeline);
diff --git a/lib/pipeline/rte_swx_pipeline.h b/lib/pipeline/rte_swx_pipeline.h
index adc7fa53b7..184027ba44 100644
--- a/lib/pipeline/rte_swx_pipeline.h
+++ b/lib/pipeline/rte_swx_pipeline.h
@@ -163,6 +163,16 @@ rte_swx_pipeline_port_out_config(struct rte_swx_pipeline *p,
  * Packet mirroring
  */
 
+/** Default number of packet mirroring slots. */
+#ifndef RTE_SWX_PACKET_MIRRORING_SLOTS_DEFAULT
+#define RTE_SWX_PACKET_MIRRORING_SLOTS_DEFAULT 4
+#endif
+
+/** Default maxiumum number of packet mirroring sessions. */
+#ifndef RTE_SWX_PACKET_MIRRORING_SESSIONS_DEFAULT
+#define RTE_SWX_PACKET_MIRRORING_SESSIONS_DEFAULT 64
+#endif
+
 /** Packet mirroring parameters. */
 struct rte_swx_pipeline_mirroring_params {
 	/** Number of packet mirroring slots. */
-- 
2.17.1