libibverbs: Fix ABI_placeholder1 and ABI_placeholder2 assignment

[ Upstream commit 88789b7 ]

The assignment of ABI_placeholder1 and ABI_placeholder2 must be
after the provider populated context_ex->ibv_create_flow and
context_ex->ibv_destroy_flow.

Applications, which compiled against old libibverbs released between
commit 501b53b and 1111cf9, will fail if they are linked
with libibverbs released after 1111cf9 and call ibv_create_flow.

[1] 501b53b ("Fix create/destroy flow API")

Fixes: 1111cf9 ("verbs: Always allocate a verbs_context")
Signed-off-by: Honggang Li <honli@redhat.com>
Signed-off-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com>

libibverbs/device.c

@@ -216,23 +216,6 @@ int verbs_init_context(struct verbs_context *context_ex,
 	context_ex->context.abi_compat = __VERBS_ABI_IS_EXTENDED;
 	context_ex->sz = sizeof(*context_ex);
 
-	/*
-	 * In order to maintain backward/forward binary compatibility
-	 * with apps compiled against libibverbs-1.1.8 that use the
-	 * flow steering addition, we need to set the two
-	 * ABI_placeholder entries to match the driver set flow
-	 * entries.  This is because apps compiled against
-	 * libibverbs-1.1.8 use an inline ibv_create_flow and
-	 * ibv_destroy_flow function that looks in the placeholder
-	 * spots for the proper entry points.  For apps compiled
-	 * against libibverbs-1.1.9 and later, the inline functions
-	 * will be looking in the right place.
-	 */
-	context_ex->ABI_placeholder1 =
-		(void (*)(void))context_ex->ibv_create_flow;
-	context_ex->ABI_placeholder2 =
-		(void (*)(void))context_ex->ibv_destroy_flow;
-
 	context_ex->priv = calloc(1, sizeof(*context_ex->priv));
 	if (!context_ex->priv) {
 		errno = ENOMEM;
@@ -313,6 +296,23 @@ LATEST_SYMVER_FUNC(ibv_open_device, 1_1, "IBVERBS_1.1",
 		context_ex->create_cq_ex = __lib_ibv_create_cq_ex;
 	}
 
+	/*
+	 * In order to maintain backward/forward binary compatibility
+	 * with apps compiled against libibverbs-1.1.8 that use the
+	 * flow steering addition, we need to set the two
+	 * ABI_placeholder entries to match the driver set flow
+	 * entries.  This is because apps compiled against
+	 * libibverbs-1.1.8 use an inline ibv_create_flow and
+	 * ibv_destroy_flow function that looks in the placeholder
+	 * spots for the proper entry points.  For apps compiled
+	 * against libibverbs-1.1.9 and later, the inline functions
+	 * will be looking in the right place.
+	 */
+	context_ex->ABI_placeholder1 =
+		(void (*)(void))context_ex->ibv_create_flow;
+	context_ex->ABI_placeholder2 =
+		(void (*)(void))context_ex->ibv_destroy_flow;
+
 	return &context_ex->context;
 }