In RCU defer queue mode, tbl8_free() pushes a freed tbl8 group into
the defer queue, and the group stays allocated until its reclamation.
rte_lpm_delete_all() clears all tbl8 groups, including the ones still
waiting in the defer queue, so they can be allocated again for new
rules. When the deferred reclamation runs later, it invalidates such
a group while it is in use: lookups for the new rule miss, and the
group can be allocated once more to another rule, so the lookups
return the next hop of that rule.
Wait for the readers and reclaim the defer queue in
rte_lpm_delete_all(), and add a unit test for this case.
Fixes: 8a9f8564e9f9 ("lpm: implement RCU rule reclamation")
Cc: [email protected]
Signed-off-by: Andrey Mokrushin <[email protected]>
---
app/test/test_lpm.c | 75 ++++++++++++++++++++++++++++++++++++++++++++-
lib/lpm/rte_lpm.c | 11 +++++++
2 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/app/test/test_lpm.c b/app/test/test_lpm.c
index f4a8031..4baab9e 100644
--- a/app/test/test_lpm.c
+++ b/app/test/test_lpm.c
@@ -44,6 +44,7 @@ static int32_t test18(void);
static int32_t test19(void);
static int32_t test20(void);
static int32_t test21(void);
+static int32_t test22(void);
rte_lpm_test tests[] = {
/* Test Cases */
@@ -68,7 +69,8 @@ rte_lpm_test tests[] = {
test18,
test19,
test20,
- test21
+ test21,
+ test22
};
#define MAX_DEPTH 32
@@ -1563,6 +1565,77 @@ test21(void)
return (status == 0) ? PASS : -1;
}
+/*
+ * rte_lpm_delete_all with RCU QSBR in defer queue mode.
+ * - Add a rule using a tbl8 group, delete it: the group goes to the
+ * defer queue
+ * - Delete all rules, add another rule using a tbl8 group
+ * - Add one more rule needing a tbl8 group: there is none left
+ * - Check that the second rule is still found
+ */
+int32_t
+test22(void)
+{
+ struct rte_lpm *lpm = NULL;
+ struct rte_lpm_config config;
+ size_t sz;
+ struct rte_rcu_qsbr *qsv;
+ int32_t status;
+ uint32_t ip1, ip2, ip3, next_hop_return;
+ uint8_t depth = 25;
+ struct rte_lpm_rcu_config rcu_cfg = {0};
+
+ config.max_rules = MAX_RULES;
+ config.number_tbl8s = 1;
+ config.flags = 0;
+
+ lpm = rte_lpm_create(__func__, SOCKET_ID_ANY, &config);
+ TEST_LPM_ASSERT(lpm != NULL);
+
+ /* Create RCU QSBR variable */
+ sz = rte_rcu_qsbr_get_memsize(1);
+ qsv = (struct rte_rcu_qsbr *)rte_zmalloc_socket(NULL, sz,
+ RTE_CACHE_LINE_SIZE, SOCKET_ID_ANY);
+ TEST_LPM_ASSERT(qsv != NULL);
+
+ status = rte_rcu_qsbr_init(qsv, 1);
+ TEST_LPM_ASSERT(status == 0);
+
+ rcu_cfg.v = qsv;
+ rcu_cfg.mode = RTE_LPM_QSBR_MODE_DQ;
+ /* Attach RCU QSBR to LPM table */
+ status = rte_lpm_rcu_qsbr_add(lpm, &rcu_cfg);
+ TEST_LPM_ASSERT(status == 0);
+
+ ip1 = RTE_IPV4(192, 0, 2, 0);
+ ip2 = RTE_IPV4(198, 51, 100, 0);
+ ip3 = RTE_IPV4(203, 0, 113, 0);
+
+ status = rte_lpm_add(lpm, ip1, depth, 1);
+ TEST_LPM_ASSERT(status == 0);
+ status = rte_lpm_delete(lpm, ip1, depth);
+ TEST_LPM_ASSERT(status == 0);
+
+ rte_lpm_delete_all(lpm);
+
+ status = rte_lpm_add(lpm, ip2, depth, 2);
+ TEST_LPM_ASSERT(status == 0);
+
+ /* No tbl8 group left, the one used by ip2 must not be reclaimed */
+ status = rte_lpm_add(lpm, ip3, depth, 3);
+ TEST_LPM_ASSERT(status != 0);
+
+ status = rte_lpm_lookup(lpm, ip2, &next_hop_return);
+ TEST_LPM_ASSERT(status == 0 && next_hop_return == 2);
+ status = rte_lpm_lookup(lpm, ip3, &next_hop_return);
+ TEST_LPM_ASSERT(status != 0);
+
+ rte_lpm_free(lpm);
+ rte_free(qsv);
+
+ return PASS;
+}
+
/*
* Do all unit tests.
*/
diff --git a/lib/lpm/rte_lpm.c b/lib/lpm/rte_lpm.c
index 0d1afe0..9ddb079 100644
--- a/lib/lpm/rte_lpm.c
+++ b/lib/lpm/rte_lpm.c
@@ -1268,4 +1268,15 @@ rte_lpm_delete_all(struct rte_lpm *lpm)
/* Delete all rules form the rules table. */
memset(i_lpm->rules_tbl, 0, sizeof(i_lpm->rules_tbl[0]) *
i_lpm->max_rules);
+
+ /*
+ * The tbl8 groups waiting in the defer queue have just been
+ * cleared and may be allocated again. Reclaim them now, otherwise
+ * the deferred reclamation would invalidate a reused group.
+ */
+ if (i_lpm->dq != NULL) {
+ rte_rcu_qsbr_synchronize(i_lpm->v, RTE_QSBR_THRID_INVALID);
+ rte_rcu_qsbr_dq_reclaim(i_lpm->dq, i_lpm->number_tbl8s,
+ NULL, NULL, NULL);
+ }
}
--
2.56.0
