test/rcu: fix build for small number of cores

If the RTE_MAX_LCORE is less than 10, a compilation error is generated:
app/test/test_rcu_qsbr.c:234:10: error: comparison of integer
expressions of different signedness: ‘unsigned int’ and ‘int’
[-Werror=sign-compare]

The cause is (RTE_MAX_LCORE - 10) results in a negative value.

To fix, use rte_rand() to find a number between 0 and RTE_MAX_LCORE.

Fixes: b87089b0bb19 ("test/rcu: add API and functional tests")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>

diff --git a/app/test/test_rcu_qsbr.c b/app/test/test_rcu_qsbr.c
index 85d80e0..b60dc50 100644 (file)
--- a/app/test/test_rcu_qsbr.c
+++ b/app/test/test_rcu_qsbr.c
@@ -9,6 +9,7 @@
 #include <rte_hash_crc.h>
 #include <rte_malloc.h>
 #include <rte_cycles.h>
+#include <rte_random.h>
 #include <unistd.h>
 
 #include "test.h"
@@ -168,6 +169,7 @@ test_rcu_qsbr_thread_unregister(void)
 {
        unsigned int num_threads[3] = {1, RTE_MAX_LCORE, 1};
        unsigned int i, j;
+       unsigned int skip_thread_id;
        uint64_t token;
        int ret;
 
@@ -227,10 +229,11 @@ test_rcu_qsbr_thread_unregister(void)
                token = rte_rcu_qsbr_start(t[0]);
                TEST_RCU_QSBR_RETURN_IF_ERROR(
                        (token != (TEST_RCU_QSBR_CNT_INIT + 1)), "QSBR Start");
+               skip_thread_id = rte_rand() % RTE_MAX_LCORE;
                /* Update quiescent state counter */
                for (i = 0; i < num_threads[j]; i++) {
                        /* Skip one update */
-                       if (i == (RTE_MAX_LCORE - 10))
+                       if ((j == 1) && (i == skip_thread_id))
                                continue;
                        rte_rcu_qsbr_quiescent(t[0],
                                (j == 2) ? (RTE_MAX_LCORE - 1) : i);
@@ -242,7 +245,7 @@ test_rcu_qsbr_thread_unregister(void)
                        TEST_RCU_QSBR_RETURN_IF_ERROR((ret == 0),
                                                "Non-blocking QSBR check");
                        /* Update the previously skipped thread */
-                       rte_rcu_qsbr_quiescent(t[0], RTE_MAX_LCORE - 10);
+                       rte_rcu_qsbr_quiescent(t[0], skip_thread_id);
                }
 
                /* Validate the updates */