[PATCH 2/2] cyclictest: simplify rstat_setup

[Lukas Beckmann <lbckmnn@mailbox.org>]

The shm file is truncated to zero each time before it is written.
It does not make sense to truncate it to something non zero on setup or
to mlock it.

Signed-off-by: Lukas Beckmann <lbckmnn@mailbox.org>
---
 src/cyclictest/cyclictest.c | 89 ++++++-------------------------------
 1 file changed, 13 insertions(+), 76 deletions(-)

diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 960c905..7b959ac 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -1771,33 +1771,6 @@ static void trigger_update(struct thread_param *par, int diff, int64_t ts)
 	pthread_mutex_unlock(&trigger_lock);
 }
 
-/* Running status shared memory open */
-static int rstat_shm_open(void)
-{
-	int fd;
-	pid_t pid;
-
-	pid = getpid();
-
-	snprintf(shm_name, SHM_BUF_SIZE, "%s%d", "/cyclictest", pid);
-
-	errno = 0;
-	fd = shm_unlink(shm_name);
-
-	if ((fd == -1) && (errno != ENOENT)) {
-		fprintf(stderr, "ERROR: shm_unlink %s\n", strerror(errno));
-		return fd;
-	}
-
-	errno = 9;
-	fd = shm_open(shm_name, O_RDWR|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
-	if (fd == -1)
-		fprintf(stderr, "ERROR: shm_open %s\n", strerror(errno));
-
-	rstat_fd = fd;
-
-	return fd;
-}
 
 static int rstat_ftruncate(int fd, off_t len)
 {
@@ -1811,62 +1784,26 @@ static int rstat_ftruncate(int fd, off_t len)
 	return err;
 }
 
-static void *rstat_mmap(int fd)
-{
-	void *mptr;
 
-	errno = 0;
-	mptr = mmap(0, _SC_PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+static void rstat_setup(void)
+{
+	int fd;
+	pid_t pid;
 
-	if (mptr == (void*)-1)
-		fprintf(stderr, "ERROR: mmap, %s\n", strerror(errno));
+	pid = getpid();
 
-	return mptr;
-}
+	snprintf(shm_name, SHM_BUF_SIZE, "%s%d", "/cyclictest", pid);
 
-static int rstat_mlock(void *mptr)
-{
-	int err;
+	fd = shm_unlink(shm_name);
 
-	errno = 0;
-	err = mlock(mptr, _SC_PAGE_SIZE);
-	if (err == -1)
-		fprintf(stderr, "ERROR, mlock %s\n", strerror(errno));
+	if ((fd == -1) && (errno != ENOENT))
+		fprintf(stderr, "ERROR: shm_unlink %s\n", strerror(errno));
 
-	return err;
-}
+	fd = shm_open(shm_name, O_RDWR|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
+	if (fd == -1)
+		fprintf(stderr, "ERROR: shm_open %s\n", strerror(errno));
 
-static void rstat_setup(void)
-{
-	int res;
-	void *mptr = NULL;
-
-	int sfd = rstat_shm_open();
-	if (sfd < 0)
-		goto rstat_err;
-
-	res = rstat_ftruncate(sfd, _SC_PAGE_SIZE);
-	if (res)
-		goto rstat_err1;
-
-	mptr = rstat_mmap(sfd);
-	if (mptr == MAP_FAILED)
-		goto rstat_err1;
-
-	res = rstat_mlock(mptr);
-	if (res)
-		goto rstat_err2;
-
-	return;
-
-rstat_err2:
-	munmap(mptr, _SC_PAGE_SIZE);
-rstat_err1:
-	close(sfd);
-	shm_unlink(shm_name);
-rstat_err:
-	rstat_fd = -1;
-	return;
+	rstat_fd = fd;
 }
 
 static void write_stats(FILE *f, void *data)
-- 
2.53.0