[dpdk-dev] [PATCH v4 1/4] lpm: allocation of an existing object should fail

[Olivier Matz]

Change rte_lpm*_create() functions to return NULL and set rte_errno to
EEXIST when the object name already exists. This is the behavior
described in the API documentation in the header file.

These functions were returning a pointer to the existing object in that
case, but it is a problem as the caller did not know if the object had
to be freed or not.

Doing this change also makes the lpm API more consistent with the other
APIs (mempool, rings, ...).

Fixes: 916e4f4f4e ("memory: fix for multi process support")
Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
---
 app/test/test_lpm6.c                   |  2 +-
 doc/guides/rel_notes/release_16_04.rst |  9 +++++++++
 lib/librte_lpm/rte_lpm.c               | 10 ++++++++--
 lib/librte_lpm/rte_lpm6.c              |  5 ++++-
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/app/test/test_lpm6.c b/app/test/test_lpm6.c
index 1f88d7a..b464342 100644
--- a/app/test/test_lpm6.c
+++ b/app/test/test_lpm6.c
@@ -222,7 +222,7 @@ test1(void)
 
 	/* rte_lpm6_create: lpm name == LPM2 */
 	lpm3 = rte_lpm6_create("LPM1", SOCKET_ID_ANY, &config);
-	TEST_LPM_ASSERT(lpm3 == lpm1);
+	TEST_LPM_ASSERT(lpm3 == NULL);
 
 	rte_lpm6_free(lpm1);
 	rte_lpm6_free(lpm2);
diff --git a/doc/guides/rel_notes/release_16_04.rst b/doc/guides/rel_notes/release_16_04.rst
index d6e358f..9a6fd4a 100644
--- a/doc/guides/rel_notes/release_16_04.rst
+++ b/doc/guides/rel_notes/release_16_04.rst
@@ -432,6 +432,15 @@ Libraries
 
   Fixed core dump issue on txq and swq when dropless is set to yes.
 
+* **lpm: Fixed return value when allocating an existing object.**
+
+  Changed the ``rte_lpm*_create()`` functions to return ``NULL`` and set
+  ``rte_errno`` to ``EEXIST` when the object name already exists. This is
+  the behavior described in the API documentation in the header file.
+  The previous behavior was to return a pointer to the existing object in
+  that case, preventing the caller to know if the object had to be freed
+  or not.
+
 
 Examples
 ~~~~~~~~
diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
index bd3563f..8bdf606 100644
--- a/lib/librte_lpm/rte_lpm.c
+++ b/lib/librte_lpm/rte_lpm.c
@@ -209,8 +209,11 @@ rte_lpm_create_v20(const char *name, int socket_id, int max_rules,
 		if (strncmp(name, lpm->name, RTE_LPM_NAMESIZE) == 0)
 			break;
 	}
-	if (te != NULL)
+	lpm = NULL;
+	if (te != NULL) {
+		rte_errno = EEXIST;
 		goto exit;
+	}
 
 	/* allocate tailq entry */
 	te = rte_zmalloc("LPM_TAILQ_ENTRY", sizeof(*te), 0);
@@ -280,8 +283,11 @@ rte_lpm_create_v1604(const char *name, int socket_id,
 		if (strncmp(name, lpm->name, RTE_LPM_NAMESIZE) == 0)
 			break;
 	}
-	if (te != NULL)
+	lpm = NULL;
+	if (te != NULL) {
+		rte_errno = EEXIST;
 		goto exit;
+	}
 
 	/* allocate tailq entry */
 	te = rte_zmalloc("LPM_TAILQ_ENTRY", sizeof(*te), 0);
diff --git a/lib/librte_lpm/rte_lpm6.c b/lib/librte_lpm/rte_lpm6.c
index 4c44cd7..ba4353c 100644
--- a/lib/librte_lpm/rte_lpm6.c
+++ b/lib/librte_lpm/rte_lpm6.c
@@ -182,8 +182,11 @@ rte_lpm6_create(const char *name, int socket_id,
 		if (strncmp(name, lpm->name, RTE_LPM6_NAMESIZE) == 0)
 			break;
 	}
-	if (te != NULL)
+	lpm = NULL;
+	if (te != NULL) {
+		rte_errno = EEXIST;
 		goto exit;
+	}
 
 	/* allocate tailq entry */
 	te = rte_zmalloc("LPM6_TAILQ_ENTRY", sizeof(*te), 0);
-- 
2.1.4