[dpdk-dev] [PATCH v2] mempool: fix non-IO flag inference

[Dmitry Kozlyuk]

When mempool had been created with RTE_MEMPOOL_F_NO_IOVA_CONTIG flag
but later populated with valid IOVA, RTE_MEMPOOL_F_NON_IO was unset,
while it should be kept. The unit test did not catch this
because rte_mempool_populate_default() it used was populating
with RTE_BAD_IOVA.

Keep setting RTE_MEMPOOL_NON_IO at an empty mempool creation
and add an assert for it in the unit test (remove the separate case).
Do not reset the flag if RTE_MEMPOOL_F_ON_IOVA_CONTIG is set.

Fixes: 11541c5c81dd ("mempool: add non-IO flag")

Signed-off-by: Dmitry Kozlyuk <dkozlyuk at nvidia.com>
---
v2: IOVA mode has nothing to do with populating the mempool,
    so logic related to it is removed and the unit test simplified.

 app/test/test_mempool.c   | 45 +++++++++++++++++----------------------
 lib/mempool/rte_mempool.c |  4 ++--
 2 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/app/test/test_mempool.c b/app/test/test_mempool.c
index 4f399b461d..4b0f6b0e7f 100644
--- a/app/test/test_mempool.c
+++ b/app/test/test_mempool.c
@@ -740,16 +740,31 @@ test_mempool_events_safety(void)
 static int
 test_mempool_flag_non_io_set_when_no_iova_contig_set(void)
 {
+	void *virt = NULL;
+	rte_iova_t iova;
+	size_t size = MEMPOOL_ELT_SIZE * 16;
 	struct rte_mempool *mp = NULL;
 	int ret;
 
+	virt = rte_malloc("test_mempool", size, rte_mem_page_size());
+	RTE_TEST_ASSERT_NOT_NULL(virt, "Cannot allocate memory");
+	iova = rte_mem_virt2iova(virt);
+	RTE_TEST_ASSERT_NOT_EQUAL(iova,  RTE_BAD_IOVA, "Cannot get IOVA");
 	mp = rte_mempool_create_empty("empty", MEMPOOL_SIZE,
 				      MEMPOOL_ELT_SIZE, 0, 0,
 				      SOCKET_ID_ANY, RTE_MEMPOOL_F_NO_IOVA_CONTIG);
 	RTE_TEST_ASSERT_NOT_NULL(mp, "Cannot create mempool: %s",
 				 rte_strerror(rte_errno));
 	rte_mempool_set_ops_byname(mp, rte_mbuf_best_mempool_ops(), NULL);
-	ret = rte_mempool_populate_default(mp);
+
+	RTE_TEST_ASSERT(mp->flags & RTE_MEMPOOL_F_NON_IO,
+			"NON_IO flag is not set on an empty mempool");
+
+	/*
+	 * Always use valid IOVA so that populate() has no other reason
+	 * to infer that the mempool cannot be used for IO.
+	 */
+	ret = rte_mempool_populate_iova(mp, virt, iova, size, NULL, NULL);
 	RTE_TEST_ASSERT(ret > 0, "Failed to populate mempool: %s",
 			rte_strerror(-ret));
 	RTE_TEST_ASSERT(mp->flags & RTE_MEMPOOL_F_NON_IO,
@@ -757,6 +772,7 @@ test_mempool_flag_non_io_set_when_no_iova_contig_set(void)
 	ret = TEST_SUCCESS;
 exit:
 	rte_mempool_free(mp);
+	rte_free(virt);
 	return ret;
 }
 
@@ -785,6 +801,9 @@ test_mempool_flag_non_io_unset_when_populated_with_valid_iova(void)
 	RTE_TEST_ASSERT_NOT_NULL(mp, "Cannot create mempool: %s",
 				 rte_strerror(rte_errno));
 
+	RTE_TEST_ASSERT(mp->flags & RTE_MEMPOOL_F_NON_IO,
+			"NON_IO flag is not set on an empty mempool");
+
 	ret = rte_mempool_populate_iova(mp, RTE_PTR_ADD(virt, 1 * block_size),
 					RTE_BAD_IOVA, block_size, NULL, NULL);
 	RTE_TEST_ASSERT(ret > 0, "Failed to populate mempool: %s",
@@ -812,28 +831,6 @@ test_mempool_flag_non_io_unset_when_populated_with_valid_iova(void)
 	return ret;
 }
 
-static int
-test_mempool_flag_non_io_unset_by_default(void)
-{
-	struct rte_mempool *mp;
-	int ret;
-
-	mp = rte_mempool_create_empty("empty", MEMPOOL_SIZE,
-				      MEMPOOL_ELT_SIZE, 0, 0,
-				      SOCKET_ID_ANY, 0);
-	RTE_TEST_ASSERT_NOT_NULL(mp, "Cannot create mempool: %s",
-				 rte_strerror(rte_errno));
-	ret = rte_mempool_populate_default(mp);
-	RTE_TEST_ASSERT_EQUAL(ret, (int)mp->size, "Failed to populate mempool: %s",
-			      rte_strerror(-ret));
-	RTE_TEST_ASSERT(!(mp->flags & RTE_MEMPOOL_F_NON_IO),
-			"NON_IO flag is set by default");
-	ret = TEST_SUCCESS;
-exit:
-	rte_mempool_free(mp);
-	return ret;
-}
-
 #pragma pop_macro("RTE_TEST_TRACE_FAILURE")
 
 static int
@@ -1022,8 +1019,6 @@ test_mempool(void)
 		GOTO_ERR(ret, err);
 
 	/* test NON_IO flag inference */
-	if (test_mempool_flag_non_io_unset_by_default() < 0)
-		GOTO_ERR(ret, err);
 	if (test_mempool_flag_non_io_set_when_no_iova_contig_set() < 0)
 		GOTO_ERR(ret, err);
 	if (test_mempool_flag_non_io_unset_when_populated_with_valid_iova() < 0)
diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
index b75d26c82a..f66a561d05 100644
--- a/lib/mempool/rte_mempool.c
+++ b/lib/mempool/rte_mempool.c
@@ -372,8 +372,8 @@ rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
 	STAILQ_INSERT_TAIL(&mp->mem_list, memhdr, next);
 	mp->nb_mem_chunks++;
 
-	/* At least some objects in the pool can now be used for IO. */
-	if (iova != RTE_BAD_IOVA)
+	/* Check if at least some objects in the pool are now usable for IO. */
+	if (!(mp->flags & RTE_MEMPOOL_F_NO_IOVA_CONTIG) && iova != RTE_BAD_IOVA)
 		mp->flags &= ~RTE_MEMPOOL_F_NON_IO;
 
 	/* Report the mempool as ready only when fully populated. */
-- 
2.25.1