[LTP] [PATCH v5] dio_truncate.c test refactory with LTP API

[Cyril Hrubis]

Hi!
Pushed with minor changes, thanks.

Apart from simple formatting fixes the most complicated change was
removal of the loop that waits the children at the end of the run().
Since if any of the children returns prematurely the waitpid() for the
pid will fail and the test will exit with TBROK. The easiest solution
was simply to remove the loop since the children exit with 0 now the
library will collect them for us just fine.

Full diff:

diff --git a/testcases/kernel/io/ltp-aiodio/dio_truncate.c b/testcases/kernel/io/ltp-aiodio/dio_truncate.c
index 3681c9bdb..68c10ac7a 100644
--- a/testcases/kernel/io/ltp-aiodio/dio_truncate.c
+++ b/testcases/kernel/io/ltp-aiodio/dio_truncate.c
@@ -10,13 +10,17 @@
  *
  * This test is mixing direct I/O and truncate operations checking if they can
  * be used together at the same time. Multiple children are spawned to read a
- * file that is edited using DIO write/read operations. Algorithm:
+ * file that is written to using direct I/O and truncated in a loop.
+ *
+ * [Algorithm]
+ *
  * - Spawn multiple children which start to read on 'file'
  * - Parent start to fill and truncate 'file' many times with zero char when
  *   children are reading
  * - Parent start to fill and truncate a junk file many times with non-zero char
+ *
  * If no issues occur on direct IO/truncate operations and the file always
- * contains non-zero characters, test PASS. Otherwise, test will FAIL.
+ * contains zero characters, test PASS. Otherwise, test will FAIL.
  */
 
 #define _GNU_SOURCE
@@ -53,7 +57,8 @@ static char *check_zero(char *buf, int size)
 		buf++;
 		size--;
 	}
-	return 0; /* all zeros */
+
+	return 0;
 }
 
 static void dio_read(const char *filename, size_t bs)
@@ -67,19 +72,19 @@ static void dio_read(const char *filename, size_t bs)
 	while ((fd = open(filename, O_RDONLY | O_DIRECT, 0666)) < 0)
 		usleep(100);
 
-	tst_res(TINFO, "child reading file");
+	tst_res(TINFO, "child %i reading file", getpid());
 	while (*run_child) {
 		off_t offset;
 		char *bufoff;
 
-		/* read the file, checking for zeros */
 		offset = SAFE_LSEEK(fd, SEEK_SET, 0);
 		do {
 			r = read(fd, bufptr, 64 * 1024);
 			if (r > 0) {
 				bufoff = check_zero(bufptr, r);
 				if (bufoff) {
-					tst_res(TINFO, "non-zero read at offset %p", offset + bufoff);
+					tst_res(TINFO, "non-zero read at offset %zu",
+						offset + (bufoff - bufptr));
 					free(bufptr);
 					SAFE_CLOSE(fd);
 					return;
@@ -91,8 +96,6 @@ static void dio_read(const char *filename, size_t bs)
 
 	free(bufptr);
 	SAFE_CLOSE(fd);
-
-	tst_res(TPASS, "zero buffer only after truncate");
 }
 
 static void dio_append(const char *path, char pattern, size_t bs, size_t bcount)
@@ -128,7 +131,6 @@ static void run(void)
 	char *filename = "file";
 	int filesize = FILE_SIZE;
 	int num_children = NUM_CHILDREN;
-	int pid[NUM_CHILDREN];
 	int status;
 	int i;
 	int fail = 0;
@@ -136,13 +138,14 @@ static void run(void)
 	*run_child = 1;
 
 	for (i = 0; i < num_children; i++) {
-		pid[i] = SAFE_FORK();
-		if (pid[i] == 0) {
+		if (!SAFE_FORK()) {
 			dio_read(filename, filesize);
 			return;
 		}
 	}
 
+	tst_res(TINFO, "parent writes/truncates the file");
+
 	for (i = 0; i < 100; i++) {
 		dio_append(filename, 0, filesize, 100);
 		SAFE_TRUNCATE(filename, 0);
@@ -161,9 +164,6 @@ static void run(void)
 		tst_res(TPASS, "All bytes read were zeroed");
 
 	*run_child = 0;
-
-	for (i = 0; i < num_children; i++)
-		SAFE_WAITPID(pid[i], &status, 0);
 }
 
 static struct tst_test test = {

-- 
Cyril Hrubis
chrubis@suse.cz