[PATCH v2 2/3] selftests/mm: emit TAP header and use TAP skip in mremap_test

mremap_test calls ksft_set_plan() without ksft_print_header(), and its
get_mmap_min_addr() skip path uses a bare exit(KSFT_SKIP) that prints no
TAP line, so its output is not valid KTAP.  Add the header and switch
the skip to ksft_exit_skip().

Also fix two more KTAP compliance issues spotted in review:

- get_mmap_min_addr() calls strerror(errno) after fclose(), which may
  clobber errno; save errno before fclose() instead.

- Some ksft_*() messages embed "\n\t", so the text after each embedded
  newline is printed without the "# " prefix.  Split those into separate
  messages.

Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Reviewed-by: Sarthak Sharma <[email protected]>
Signed-off-by: Song Hu <[email protected]>
---
 tools/testing/selftests/mm/mremap_test.c | 41 +++++++++++++-----------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c
index 131d9d6db867..28f151daabe4 100644
--- a/tools/testing/selftests/mm/mremap_test.c
+++ b/tools/testing/selftests/mm/mremap_test.c
@@ -111,18 +111,17 @@ static unsigned long long get_mmap_min_addr(void)
 		return addr;
 
 	fp = fopen("/proc/sys/vm/mmap_min_addr", "r");
-	if (fp == NULL) {
-		ksft_print_msg("Failed to open /proc/sys/vm/mmap_min_addr: %s\n",
-			strerror(errno));
-		exit(KSFT_SKIP);
-	}
+	if (!fp)
+		ksft_exit_skip("Failed to open /proc/sys/vm/mmap_min_addr: %s\n",
+			       strerror(errno));
 
 	n_matched = fscanf(fp, "%llu", &addr);
 	if (n_matched != 1) {
-		ksft_print_msg("Failed to read /proc/sys/vm/mmap_min_addr: %s\n",
-			strerror(errno));
+		int err = errno;
+
 		fclose(fp);
-		exit(KSFT_SKIP);
+		ksft_exit_skip("Failed to read /proc/sys/vm/mmap_min_addr: %s\n",
+			       strerror(err));
 	}
 
 	fclose(fp);
@@ -1164,10 +1163,11 @@ static void run_mremap_test_case(struct test test_case, int *failures,
 					    rand_addr);
 
 	if (remap_time < 0) {
-		if (test_case.expect_failure)
-			ksft_test_result_xfail("%s\n\tExpected mremap failure\n",
-					      test_case.name);
-		else {
+		if (test_case.expect_failure) {
+			ksft_print_msg("%s: expected mremap failure\n",
+				       test_case.name);
+			ksft_test_result_xfail("%s\n", test_case.name);
+		} else {
 			ksft_test_result_fail("%s\n", test_case.name);
 			*failures += 1;
 		}
@@ -1177,11 +1177,13 @@ static void run_mremap_test_case(struct test test_case, int *failures,
 		 * was faulted in.
 		 */
 		if (threshold_mb == VALIDATION_NO_THRESHOLD ||
-		    test_case.config.region_size <= threshold_mb * _1MB)
-			ksft_test_result_pass("%s\n\tmremap time: %12lldns\n",
-					      test_case.name, remap_time);
-		else
+		    test_case.config.region_size <= threshold_mb * _1MB) {
+			ksft_print_msg("%s: mremap time: %12lldns\n",
+				       test_case.name, remap_time);
 			ksft_test_result_pass("%s\n", test_case.name);
+		} else {
+			ksft_test_result_pass("%s\n", test_case.name);
+		}
 	}
 }
 
@@ -1250,13 +1252,16 @@ int main(int argc, char **argv)
 	time_t t;
 	FILE *maps_fp;
 
+	ksft_print_header();
+
 	pattern_seed = (unsigned int) time(&t);
 
 	if (parse_args(argc, argv, &threshold_mb, &pattern_seed) < 0)
 		exit(EXIT_FAILURE);
 
-	ksft_print_msg("Test configs:\n\tthreshold_mb=%u\n\tpattern_seed=%u\n\n",
-		       threshold_mb, pattern_seed);
+	ksft_print_msg("Test configs:\n");
+	ksft_print_msg("threshold_mb=%u\n", threshold_mb);
+	ksft_print_msg("pattern_seed=%u\n", pattern_seed);
 
 	/*
 	 * set preallocated random array according to test configs; see the
-- 
2.43.0