[dpdk-dev] [PATCH v2] lpm: fix unchecked return value

[Ruifeng Wang]

Coverity complains about unchecked return value of rte_rcu_qsbr_dq_enqueue.
By default, defer queue size is big enough to hold all tbl8 groups. When
enqueue fails, return error to the user to indicate system issue.

Coverity issue: 360832
Fixes: 8a9f8564e9f9 ("lpm: implement RCU rule reclamation")

Signed-off-by: Ruifeng Wang <ruifeng.wang at arm.com>
---
v2:
Converted return value to conform to LPM API convention. (Vladimir)

 lib/librte_lpm/rte_lpm.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
index 2db9e16a2..757436f49 100644
--- a/lib/librte_lpm/rte_lpm.c
+++ b/lib/librte_lpm/rte_lpm.c
@@ -532,11 +532,12 @@ tbl8_alloc(struct rte_lpm *lpm)
 	return group_idx;
 }
 
-static void
+static int32_t
 tbl8_free(struct rte_lpm *lpm, uint32_t tbl8_group_start)
 {
 	struct rte_lpm_tbl_entry zero_tbl8_entry = {0};
 	struct __rte_lpm *internal_lpm;
+	int status;
 
 	internal_lpm = container_of(lpm, struct __rte_lpm, lpm);
 	if (internal_lpm->v == NULL) {
@@ -552,9 +553,15 @@ tbl8_free(struct rte_lpm *lpm, uint32_t tbl8_group_start)
 				__ATOMIC_RELAXED);
 	} else if (internal_lpm->rcu_mode == RTE_LPM_QSBR_MODE_DQ) {
 		/* Push into QSBR defer queue. */
-		rte_rcu_qsbr_dq_enqueue(internal_lpm->dq,
+		status = rte_rcu_qsbr_dq_enqueue(internal_lpm->dq,
 				(void *)&tbl8_group_start);
+		if (status == 1) {
+			RTE_LOG(ERR, LPM, "Failed to push QSBR FIFO\n");
+			return -rte_errno;
+		}
 	}
+
+	return 0;
 }
 
 static __rte_noinline int32_t
@@ -1040,7 +1047,7 @@ delete_depth_big(struct rte_lpm *lpm, uint32_t ip_masked,
 #define group_idx next_hop
 	uint32_t tbl24_index, tbl8_group_index, tbl8_group_start, tbl8_index,
 			tbl8_range, i;
-	int32_t tbl8_recycle_index;
+	int32_t tbl8_recycle_index, status = 0;
 
 	/*
 	 * Calculate the index into tbl24 and range. Note: All depths larger
@@ -1097,7 +1104,7 @@ delete_depth_big(struct rte_lpm *lpm, uint32_t ip_masked,
 		 */
 		lpm->tbl24[tbl24_index].valid = 0;
 		__atomic_thread_fence(__ATOMIC_RELEASE);
-		tbl8_free(lpm, tbl8_group_start);
+		status = tbl8_free(lpm, tbl8_group_start);
 	} else if (tbl8_recycle_index > -1) {
 		/* Update tbl24 entry. */
 		struct rte_lpm_tbl_entry new_tbl24_entry = {
@@ -1113,10 +1120,10 @@ delete_depth_big(struct rte_lpm *lpm, uint32_t ip_masked,
 		__atomic_store(&lpm->tbl24[tbl24_index], &new_tbl24_entry,
 				__ATOMIC_RELAXED);
 		__atomic_thread_fence(__ATOMIC_RELEASE);
-		tbl8_free(lpm, tbl8_group_start);
+		status = tbl8_free(lpm, tbl8_group_start);
 	}
 #undef group_idx
-	return 0;
+	return status;
 }
 
 /*
-- 
2.17.1