[LTP] [PATCH] fanotify/fanotify04: Bugfix for running with option of "-i 500"

[Zhao Gongyi]

When we running the testcase with option of "-i 500", the test
will fail:
...
fanotify04.c:163: TPASS: No event as expected
fanotify04.c:71: TPASS: fanotify_mark (3, FAN_MARK_ADD | 0, FAN_OPEN, AT_FDCWD, 'symlink_160172') succeeded
fanotify04.c:127: TPASS: event generated properly for type 100000
fanotify04.c:113: TBROK: read(3,0x55c783185280,0) failed, returned -1: EINVAL (22)
...

Signed-off-by: Zhao Gongyi <zhaogongyi@huawei.com>
---
 .../kernel/syscalls/fanotify/fanotify04.c      | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/testcases/kernel/syscalls/fanotify/fanotify04.c b/testcases/kernel/syscalls/fanotify/fanotify04.c
index b23d7a9a3..8dedcf34a 100644
--- a/testcases/kernel/syscalls/fanotify/fanotify04.c
+++ b/testcases/kernel/syscalls/fanotify/fanotify04.c
@@ -24,11 +24,8 @@
 #ifdef HAVE_SYS_FANOTIFY_H
 #include "fanotify.h"

-#define EVENT_MAX 1024
 /* size of the event structure, not counting name */
 #define EVENT_SIZE  (sizeof (struct fanotify_event_metadata))
-/* reasonable guess as to size of 1024 events */
-#define EVENT_BUF_LEN        (EVENT_MAX * EVENT_SIZE)

 #define BUF_SIZE 256
 #define TST_TOTAL 9
@@ -39,7 +36,7 @@ static char dir[BUF_SIZE];
 static int fd_notify;

 static int len;
-static char event_buf[EVENT_BUF_LEN];
+static char event_buf[EVENT_SIZE];

 static char *expect_str_fail(int expect)
 {
@@ -109,11 +106,8 @@ static void verify_event(int mask)
 	struct stat st;

 	/* Read the event */
-	ret = SAFE_READ(0, fd_notify, event_buf + len,
-			EVENT_BUF_LEN - len);
-	event = (struct fanotify_event_metadata *)&event_buf[len];
-	len += ret;
-
+	ret = SAFE_READ(0, fd_notify, event_buf, EVENT_SIZE);
+	event = (struct fanotify_event_metadata *)&event_buf;
 	if (event->mask != FAN_OPEN) {
 		tst_res(TFAIL, "got unexpected event %llx",
 			(unsigned long long)event->mask);
@@ -146,11 +140,11 @@ static void verify_no_event(void)
 {
 	int ret;

-	ret = read(fd_notify, event_buf + len, EVENT_BUF_LEN - len);
+	ret = read(fd_notify, event_buf, EVENT_SIZE);
 	if (ret != -1) {
 		struct fanotify_event_metadata *event;

-		event = (struct fanotify_event_metadata *)&event_buf[len];
+		event = (struct fanotify_event_metadata *)&event_buf;
 		tst_res(TFAIL, "seen unexpected event (mask %llx)",
 			(unsigned long long)event->mask);
 		/* Cleanup fd from the event */
@@ -158,7 +152,7 @@ static void verify_no_event(void)
 			SAFE_CLOSE(event->fd);
 	} else if (errno != EAGAIN) {
 		tst_res(TFAIL | TERRNO, "read(%d, buf, %zu) failed", fd_notify,
-			EVENT_BUF_LEN);
+			EVENT_SIZE);
 	} else {
 		tst_res(TPASS, "No event as expected");
 	}
--
2.17.1