vppinfra: fix clib_bitmap_will_expand() result inversion

Pool's pool_put_will_expand() calls clib_bitmap_will_expand(),
so every put except ones that leads to free_bitmap reallocation
will get false positive results and vice versa.

Unfortunatelly there's no related test and existing bitmap
tests are failing silently with false positive result as well.

Fortunatelly neither clib_bitmap_will_expand() nor
pool_put_will_expand() are being used by current vpp codebase.

Type: fix
Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru>
Change-Id: Id5bb900cf6a1b1002d37670f5c415c74165b5421

2 files changed, 51 insertions, 1 deletions

diff --git a/src/plugins/unittest/bitmap_test.c b/src/plugins/unittest/bitmap_test.c
index f01b8bb6811..eb232bd11e5 100644
--- a/src/plugins/unittest/bitmap_test.c
+++ b/src/plugins/unittest/bitmap_test.c
@@ -12,6 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+#include <stdbool.h>
 #include <vlib/vlib.h>
 #include <vppinfra/bitmap.h>
 
@@ -52,12 +53,42 @@ done:
 }
 
 static clib_error_t *
+check_bitmap_will_expand (const char *test_name, uword **bm, uword index,
+			  bool expected_will_expand)
+{
+  uword max_bytes = vec_max_bytes (*bm);
+  bool result;
+
+  result = clib_bitmap_will_expand (*bm, index);
+  if (result != expected_will_expand)
+    {
+      return clib_error_create (
+	"%s failed, wrong "
+	"bitmap's expansion before set (%u != %u expected)",
+	test_name, result, expected_will_expand);
+    }
+
+  *bm = clib_bitmap_set (*bm, index, 1);
+  result = vec_max_bytes (*bm) > max_bytes;
+  if (result != expected_will_expand)
+    {
+      return clib_error_create (
+	"%s failed, wrong "
+	"bitmap's expansion after set (%u != %u expected)",
+	test_name, result, expected_will_expand);
+    }
+
+  return 0;
+}
+
+static clib_error_t *
 test_bitmap_command_fn (vlib_main_t * vm,
 			unformat_input_t * input, vlib_cli_command_t * cmd)
 {
   clib_error_t *error = 0;
   uword *bm = 0;
   uword *bm2 = 0;
+  uword *bm3 = 0;
   uword *dup = 0;
 
   /*  bm should look like:
@@ -162,9 +193,28 @@ test_bitmap_command_fn (vlib_main_t * vm,
   if (error != 0)
     goto done;
 
+  error = check_bitmap_will_expand ("clib_bitmap_will_expand 1", &bm, 0, 0);
+  if (error != 0)
+    goto done;
+
+  error = check_bitmap_will_expand ("clib_bitmap_will_expand 2", &bm,
+				    vec_max_len (bm) * BITS (uword) - 1, 0);
+  if (error != 0)
+    goto done;
+
+  error = check_bitmap_will_expand ("clib_bitmap_will_expand 3", &bm,
+				    vec_max_len (bm) * BITS (uword), 1);
+  if (error != 0)
+    goto done;
+
+  error = check_bitmap_will_expand ("clib_bitmap_will_expand 4", &bm3, 0, 1);
+  if (error != 0)
+    goto done;
+
 done:
   vec_free (bm);
   vec_free (bm2);
+  vec_free (bm3);
   vec_free (dup);
 
   return error;
diff --git a/src/vppinfra/bitmap.h b/src/vppinfra/bitmap.h
index d579afd9979..abb1405d3a2 100644
--- a/src/vppinfra/bitmap.h
+++ b/src/vppinfra/bitmap.h
@@ -208,7 +208,7 @@ clib_bitmap_set (uword * ai, uword i, uword value)
 always_inline u8
 clib_bitmap_will_expand (uword *ai, uword i)
 {
-  return (i / BITS (ai[0])) < vec_max_len (ai);
+  return (i / BITS (ai[0])) >= vec_max_len (ai);
 }
 
 /** Gets the ith bit value from a bitmap