diff --git a/core/admin.m b/core/admin.m
index 4eaea8823a65b482d60a2f4d6c8434faaa09f8c6..62f58b46f83ff7253c019cfc7bad4e80ec9a7080 100644
--- a/core/admin.m
+++ b/core/admin.m
@@ -206,11 +206,11 @@ case 6:
 	}
 	goto st0;
 tr13:
-#line 247 "core/admin.rl"
+#line 246 "core/admin.rl"
 	{slab_validate(); ok(out);}
 	goto st135;
 tr20:
-#line 235 "core/admin.rl"
+#line 234 "core/admin.rl"
 	{return 0;}
 	goto st135;
 tr25:
@@ -227,7 +227,7 @@ tr25:
 		}
 	goto st135;
 tr36:
-#line 221 "core/admin.rl"
+#line 220 "core/admin.rl"
 	{strend = p;}
 #line 167 "core/admin.rl"
 	{
@@ -247,7 +247,7 @@ tr43:
 		}
 	goto st135;
 tr67:
-#line 245 "core/admin.rl"
+#line 244 "core/admin.rl"
 	{coredump(60); ok(out);}
 	goto st135;
 tr76:
@@ -266,32 +266,30 @@ tr76:
 		}
 	goto st135;
 tr98:
-#line 231 "core/admin.rl"
+#line 230 "core/admin.rl"
 	{ state = false; }
 #line 194 "core/admin.rl"
 	{
 			strstart[strend-strstart] = '\0';
-			bool ret = errinj_set_byname(strstart, state);
-			if (ret) {
-				ok(out);
-			} else {
+			if (errinj_set_byname(strstart, state)) {
 				tbuf_printf(err, "can't find error injection '%s'", strstart);
 				fail(out, err);
+			} else {
+				ok(out);
 			}
 		}
 	goto st135;
 tr101:
-#line 230 "core/admin.rl"
+#line 229 "core/admin.rl"
 	{ state = true; }
 #line 194 "core/admin.rl"
 	{
 			strstart[strend-strstart] = '\0';
-			bool ret = errinj_set_byname(strstart, state);
-			if (ret) {
-				ok(out);
-			} else {
+			if (errinj_set_byname(strstart, state)) {
 				tbuf_printf(err, "can't find error injection '%s'", strstart);
 				fail(out, err);
+			} else {
+				ok(out);
 			}
 		}
 	goto st135;
@@ -316,11 +314,11 @@ tr117:
 		}
 	goto st135;
 tr131:
-#line 238 "core/admin.rl"
+#line 237 "core/admin.rl"
 	{start(out); fiber_info(out); end(out);}
 	goto st135;
 tr137:
-#line 237 "core/admin.rl"
+#line 236 "core/admin.rl"
 	{start(out); tarantool_info(out); end(out);}
 	goto st135;
 tr146:
@@ -332,29 +330,29 @@ tr146:
 		}
 	goto st135;
 tr152:
-#line 241 "core/admin.rl"
+#line 240 "core/admin.rl"
 	{start(out); palloc_stat(out); end(out);}
 	goto st135;
 tr160:
-#line 240 "core/admin.rl"
+#line 239 "core/admin.rl"
 	{start(out); slab_stat(out); end(out);}
 	goto st135;
 tr164:
-#line 242 "core/admin.rl"
+#line 241 "core/admin.rl"
 	{start(out); stat_print(out);end(out);}
 	goto st135;
 st135:
 	if ( ++p == pe )
 		goto _test_eof135;
 case 135:
-#line 351 "core/admin.m"
+#line 349 "core/admin.m"
 	goto st0;
 tr14:
-#line 247 "core/admin.rl"
+#line 246 "core/admin.rl"
 	{slab_validate(); ok(out);}
 	goto st7;
 tr21:
-#line 235 "core/admin.rl"
+#line 234 "core/admin.rl"
 	{return 0;}
 	goto st7;
 tr26:
@@ -371,7 +369,7 @@ tr26:
 		}
 	goto st7;
 tr37:
-#line 221 "core/admin.rl"
+#line 220 "core/admin.rl"
 	{strend = p;}
 #line 167 "core/admin.rl"
 	{
@@ -391,7 +389,7 @@ tr44:
 		}
 	goto st7;
 tr68:
-#line 245 "core/admin.rl"
+#line 244 "core/admin.rl"
 	{coredump(60); ok(out);}
 	goto st7;
 tr77:
@@ -410,32 +408,30 @@ tr77:
 		}
 	goto st7;
 tr99:
-#line 231 "core/admin.rl"
+#line 230 "core/admin.rl"
 	{ state = false; }
 #line 194 "core/admin.rl"
 	{
 			strstart[strend-strstart] = '\0';
-			bool ret = errinj_set_byname(strstart, state);
-			if (ret) {
-				ok(out);
-			} else {
+			if (errinj_set_byname(strstart, state)) {
 				tbuf_printf(err, "can't find error injection '%s'", strstart);
 				fail(out, err);
+			} else {
+				ok(out);
 			}
 		}
 	goto st7;
 tr102:
-#line 230 "core/admin.rl"
+#line 229 "core/admin.rl"
 	{ state = true; }
 #line 194 "core/admin.rl"
 	{
 			strstart[strend-strstart] = '\0';
-			bool ret = errinj_set_byname(strstart, state);
-			if (ret) {
-				ok(out);
-			} else {
+			if (errinj_set_byname(strstart, state)) {
 				tbuf_printf(err, "can't find error injection '%s'", strstart);
 				fail(out, err);
+			} else {
+				ok(out);
 			}
 		}
 	goto st7;
@@ -460,11 +456,11 @@ tr118:
 		}
 	goto st7;
 tr132:
-#line 238 "core/admin.rl"
+#line 237 "core/admin.rl"
 	{start(out); fiber_info(out); end(out);}
 	goto st7;
 tr138:
-#line 237 "core/admin.rl"
+#line 236 "core/admin.rl"
 	{start(out); tarantool_info(out); end(out);}
 	goto st7;
 tr147:
@@ -476,22 +472,22 @@ tr147:
 		}
 	goto st7;
 tr153:
-#line 241 "core/admin.rl"
+#line 240 "core/admin.rl"
 	{start(out); palloc_stat(out); end(out);}
 	goto st7;
 tr161:
-#line 240 "core/admin.rl"
+#line 239 "core/admin.rl"
 	{start(out); slab_stat(out); end(out);}
 	goto st7;
 tr165:
-#line 242 "core/admin.rl"
+#line 241 "core/admin.rl"
 	{start(out); stat_print(out);end(out);}
 	goto st7;
 st7:
 	if ( ++p == pe )
 		goto _test_eof7;
 case 7:
-#line 495 "core/admin.m"
+#line 491 "core/admin.m"
 	if ( (*p) == 10 )
 		goto st135;
 	goto st0;
@@ -644,28 +640,28 @@ case 23:
 	}
 	goto tr33;
 tr33:
-#line 221 "core/admin.rl"
+#line 220 "core/admin.rl"
 	{strstart = p;}
 	goto st24;
 st24:
 	if ( ++p == pe )
 		goto _test_eof24;
 case 24:
-#line 655 "core/admin.m"
+#line 651 "core/admin.m"
 	switch( (*p) ) {
 		case 10: goto tr36;
 		case 13: goto tr37;
 	}
 	goto st24;
 tr34:
-#line 221 "core/admin.rl"
+#line 220 "core/admin.rl"
 	{strstart = p;}
 	goto st25;
 st25:
 	if ( ++p == pe )
 		goto _test_eof25;
 case 25:
-#line 669 "core/admin.m"
+#line 665 "core/admin.m"
 	switch( (*p) ) {
 		case 10: goto tr36;
 		case 13: goto tr37;
@@ -1115,28 +1111,28 @@ case 73:
 		goto tr91;
 	goto st0;
 tr91:
-#line 229 "core/admin.rl"
+#line 228 "core/admin.rl"
 	{ strstart = p; }
 	goto st74;
 st74:
 	if ( ++p == pe )
 		goto _test_eof74;
 case 74:
-#line 1126 "core/admin.m"
+#line 1122 "core/admin.m"
 	if ( (*p) == 32 )
 		goto tr92;
 	if ( 33 <= (*p) && (*p) <= 126 )
 		goto st74;
 	goto st0;
 tr92:
-#line 229 "core/admin.rl"
+#line 228 "core/admin.rl"
 	{ strend = p; }
 	goto st75;
 st75:
 	if ( ++p == pe )
 		goto _test_eof75;
 case 75:
-#line 1140 "core/admin.m"
+#line 1136 "core/admin.m"
 	switch( (*p) ) {
 		case 32: goto st75;
 		case 111: goto st76;
@@ -1828,7 +1824,7 @@ case 134:
 	_out: {}
 	}
 
-#line 253 "core/admin.rl"
+#line 252 "core/admin.rl"
 
 
 	tbuf_ltrim(fiber->rbuf, (void *)pe - (void *)fiber->rbuf->data);
diff --git a/core/admin.rl b/core/admin.rl
index fa40935328b288408ae6df90ab3f3471dbfe109e..79925f7e46840432b7bc082557afc393ee89e1c8 100644
--- a/core/admin.rl
+++ b/core/admin.rl
@@ -193,12 +193,11 @@ admin_dispatch(lua_State *L)
 
 		action set_injection {
 			strstart[strend-strstart] = '\0';
-			bool ret = errinj_set_byname(strstart, state);
-			if (ret) {
-				ok(out);
-			} else {
+			if (errinj_set_byname(strstart, state)) {
 				tbuf_printf(err, "can't find error injection '%s'", strstart);
 				fail(out, err);
+			} else {
+				ok(out);
 			}
 		}
 
diff --git a/core/errinj.m b/core/errinj.m
index 4206659ab26cbcd1cffacb5b535e185c2a789199..cb553e7d83d1ed43df5aff4997a02e280266f9a7 100644
--- a/core/errinj.m
+++ b/core/errinj.m
@@ -41,10 +41,10 @@ struct errinj errinjs[errinj_enum_MAX] = {
 	ERRINJ_LIST(ERRINJ_MEMBER)
 };
 
-static struct errinj*
+static struct errinj *
 errinj_lookup(char *name)
 {
-	int i; 
+	int i;
 	for (i = 0 ; i < errinj_enum_MAX ; i++) {
 		if (strcmp(errinjs[i].name, name) == 0)
 			return &errinjs[i];
@@ -57,7 +57,7 @@ errinj_lookup(char *name)
  *
  * @param id error injection id.
  *
- * @return error injection handle state on success, false on error.
+ * @return error injection handle state.
  */
 bool
 errinj_get(int id)
@@ -66,22 +66,6 @@ errinj_get(int id)
 	return errinjs[id].state;
 }
 
-/**
- * Get state of the error injection handle by name.
- *
- * @param name error injection name.
- *
- * @return error injection handle state on success, false on error.
- */
-bool
-errinj_get_byname(char *name)
-{
-	struct errinj *ei = errinj_lookup(name);
-	if (ei == NULL)
-		return false;
-	return ei->state;
-}
-
 /**
  * Set state of the error injection handle by id.
  *
@@ -102,16 +86,16 @@ errinj_set(int id, bool state)
  * @param name error injection name.
  * @param state error injection handle state.
  *
- * @return true on success, false on error.
+ * @return 0 on success, -1 if injection was not found.
  */
-bool
+int
 errinj_set_byname(char *name, bool state)
 {
 	struct errinj *ei = errinj_lookup(name);
 	if (ei == NULL)
-		return false;
+		return -1;
 	ei->state = state;
-	return true;
+	return 0;
 }
 
 /**
diff --git a/include/errinj.h b/include/errinj.h
index cb2f48513e3dd1c9e38b023f824f6a4e27b6a516..0b1e16193320f7bab6e5e1857ce39d3ca4292002 100644
--- a/include/errinj.h
+++ b/include/errinj.h
@@ -43,10 +43,9 @@ ENUM0(errinj_enum, ERRINJ_LIST);
 extern struct errinj errinjs[];
 
 bool errinj_get(int id);
-bool errinj_get_byname(char *name);
 
 void errinj_set(int id, bool state);
-bool errinj_set_byname(char *name, bool state);
+int errinj_set_byname(char *name, bool state);
 
 void errinj_info(struct tbuf *out);
 
diff --git a/mod/box/index.m b/mod/box/index.m
index 5d55893aa4eb2e7d354a4c13e612509628d0f016..43a9d50615c120351f780f86f81378e0c14aac4f 100644
--- a/mod/box/index.m
+++ b/mod/box/index.m
@@ -361,6 +361,8 @@ hash_iterator_free(struct iterator *iterator)
 - (void) initIterator: (struct iterator *) iterator :(void *) key
 			:(int) part_count
 {
+	(void) part_count; /* Silence gcc warning in release mode. */
+
 	struct hash_iterator *it = hash_iterator(iterator);
 
 	assert(part_count == 1);
@@ -482,6 +484,7 @@ hash_iterator_free(struct iterator *iterator)
 - (void) initIterator: (struct iterator *) iterator :(void *) field
 			:(int) part_count
 {
+	(void) part_count; /* Silence gcc warning in release mode. */
 	assert(iterator->next = hash_iterator_next);
 	assert(part_count == 1);
 
@@ -594,6 +597,7 @@ hash_iterator_free(struct iterator *iterator)
 - (void) initIterator: (struct iterator *) iterator :(void *) key
 			:(int) part_count
 {
+	(void) part_count; /* Silence gcc warning in release mode. */
 	assert(iterator->next = hash_iterator_next);
 	assert(part_count== 1);
 
diff --git a/test/box/errinj.test b/test/box/errinj.test
index d08a17cb4f3056f0b3cd0745ad7bc3a55cbcc61b..b1d65dfccce9d1fcaf15cf12fd9c79b3a07f4346 100644
--- a/test/box/errinj.test
+++ b/test/box/errinj.test
@@ -1,5 +1,5 @@
 # encoding: tarantool
-# 
+#
 import sys
 # clear statistics:
 server.stop()