Merge branch 'bpf: Fix strict mode calculation'

Mauricio Vásquez <mauricio@kinvolk.io> says:

====================

This series fixes a bad calculation of strict mode in two places. It
also updates libbpf to make it easier for the users to disable a
specific LIBBPF_STRICT_* flag.

v1 -> v2:
- remove check in libbpf_set_strict_mode()
- split in different commits

v1: https://lore.kernel.org/bpf/20220204220435.301896-1-mauricio@kinvolk.io/
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

tools/bpf/bpftool/main.c

@@ -478,14 +478,11 @@ int main(int argc, char **argv)
 	}
 
 	if (!legacy_libbpf) {
-		enum libbpf_strict_mode mode;
-
 		/* Allow legacy map definitions for skeleton generation.
 		 * It will still be rejected if users use LIBBPF_STRICT_ALL
 		 * mode for loading generated skeleton.
 		 */
-		mode = (__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS;
-		ret = libbpf_set_strict_mode(mode);
+		ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS);
 		if (ret)
 			p_err("failed to enable libbpf strict mode: %d", ret);
 	}

tools/lib/bpf/libbpf.c

@@ -156,14 +156,6 @@ enum libbpf_strict_mode libbpf_mode = LIBBPF_STRICT_NONE;
 
 int libbpf_set_strict_mode(enum libbpf_strict_mode mode)
 {
-	/* __LIBBPF_STRICT_LAST is the last power-of-2 value used + 1, so to
-	 * get all possible values we compensate last +1, and then (2*x - 1)
-	 * to get the bit mask
-	 */
-	if (mode != LIBBPF_STRICT_ALL
-	    && (mode & ~((__LIBBPF_STRICT_LAST - 1) * 2 - 1)))
-		return errno = EINVAL, -EINVAL;
-
 	libbpf_mode = mode;
 	return 0;
 }

tools/testing/selftests/bpf/prog_tests/btf.c

@@ -4580,7 +4580,7 @@ static void do_test_file(unsigned int test_num)
 	btf_ext__free(btf_ext);
 
 	/* temporary disable LIBBPF_STRICT_MAP_DEFINITIONS to test legacy maps */
-	libbpf_set_strict_mode((__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS);
+	libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS);
 	obj = bpf_object__open(test->file);
 	err = libbpf_get_error(obj);
 	if (CHECK(err, "obj: %d", err))