greybus: Loopback_test: use poll instead of inotify

Inotify does not handle sysfs events, so use poll instead.

The loopback kernel driver will send a notification when the test is
complete. So, open a poll file descriptor for every enabled device,
and after starting the test, wait for an event from each device.
After all events are received, read the total number of iterations
and make sure the test is complete.

Also, add missing stdint header which was included in inotify.
Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/tools/loopback_test.c

@@ -11,7 +11,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <sys/inotify.h>
+#include <stdint.h>
+#include <poll.h>
 #include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
@@ -22,8 +23,7 @@
 #define CSV_MAX_LINE	0x1000
 #define SYSFS_MAX_INT	0x20
 #define MAX_STR_LEN	255
-#define MAX_TIMEOUT_COUNT 5
-#define TIMEOUT_SEC 1
+#define DEFAULT_POLL_TIMEOUT_SEC 30
 #define DEFAULT_ASYNC_TIMEOUT 200000
 
 struct dict {
@@ -71,7 +71,6 @@ struct loopback_device {
 	char name[MAX_SYSFS_PATH];
 	char sysfs_entry[MAX_SYSFS_PATH];
 	char debugfs_entry[MAX_SYSFS_PATH];
-	int inotify_wd;
 	struct loopback_results results;
 };
 
@@ -86,19 +85,22 @@ struct loopback_test {
 	int aggregate_output;
 	int test_id;
 	int device_count;
-	int inotify_fd;
 	int list_devices;
 	int use_async;
 	int async_timeout;
+	int poll_timeout;
 	int async_outstanding_operations;
 	int us_wait;
 	int file_output;
+	int poll_count;
 	char test_name[MAX_STR_LEN];
 	char sysfs_prefix[MAX_SYSFS_PATH];
 	char debugfs_prefix[MAX_SYSFS_PATH];
 	struct loopback_device devices[MAX_NUM_DEVICES];
 	struct loopback_results aggregate_results;
+	struct pollfd fds[MAX_NUM_DEVICES];
 };
+
 struct loopback_test t;
 
 /* Helper macros to calculate the aggregate results for all devices */
@@ -201,6 +203,7 @@ void usage(void)
 	"   -l     list found loopback devices and exit\n"
 	"   -x     Async - Enable async transfers\n"
 	"   -o     Async Timeout - Timeout in uSec for async operations\n"
+	"   -O     Poll loop time out in seconds(max time a test is expected to last, default: 30sec)\n"
 	"   -c     Max number of outstanding operations for async operations\n"
 	"   -w     Wait in uSec between operations\n"
 	"   -z     Enable output to a CSV file (incompatible with -p)\n"
@@ -638,58 +641,51 @@ int find_loopback_devices(struct loopback_test *t)
 	return ret;
 }
 
-
-static int register_for_notification(struct loopback_test *t)
+static int open_poll_files(struct loopback_test *t)
 {
-	char buf[MAX_SYSFS_PATH];
+	struct loopback_device *dev;
+	char buf[MAX_STR_LEN];
+	char dummy;
+	int fds_idx = 0;
 	int i;
 
-	t->inotify_fd = inotify_init();
-	if (t->inotify_fd < 0) {
-		fprintf(stderr, "inotify_init fail %s\n", strerror(errno));
-		abort();
-	}
-
 	for (i = 0; i < t->device_count; i++) {
+		dev = &t->devices[i];
+
 		if (!device_enabled(t, i))
 			continue;
 
-		snprintf(buf, sizeof(buf), "%s%s", t->devices[i].sysfs_entry,
-			"iteration_count");
-
-		t->devices[i].inotify_wd = inotify_add_watch(t->inotify_fd,
-							buf, IN_MODIFY);
-		if (t->devices[i].inotify_wd < 0) {
-			fprintf(stderr, "inotify_add_watch %s fail %s\n",
-				buf, strerror(errno));
-			close(t->inotify_fd);
-			abort();
+		snprintf(buf, sizeof(buf), "%s%s", dev->sysfs_entry, "iteration_count");
+		t->fds[fds_idx].fd = open(buf, O_RDONLY);
+		if (t->fds[fds_idx].fd < 0) {
+			fprintf(stderr, "Error opening poll file!\n");
+			goto err;
 		}
+		read(t->fds[fds_idx].fd, &dummy, 1);
+		t->fds[fds_idx].events = POLLERR|POLLPRI;
+		t->fds[fds_idx].revents = 0;
+		fds_idx++;
 	}
 
+	t->poll_count = fds_idx;
+
 	return 0;
+
+err:
+	for (i = 0; i < fds_idx; i++)
+		close(t->fds[fds_idx].fd);
+
+	return -1;
 }
 
-static int unregister_for_notification(struct loopback_test *t)
+static int close_poll_files(struct loopback_test *t)
 {
 	int i;
-	int ret = 0;
-
-	for (i = 0; i < t->device_count; i++) {
-		if (!device_enabled(t, i))
-			continue;
-
-		ret = inotify_rm_watch(t->inotify_fd, t->devices[i].inotify_wd);
-		if (ret) {
-			fprintf(stderr, "inotify_rm_watch error.\n");
-			return ret;
-		}
-	}
+	for (i = 0; i < t->poll_count; i++)
+		close(t->fds[i].fd);
 
-	close(t->inotify_fd);
 	return 0;
 }
-
 static int is_complete(struct loopback_test *t)
 {
 	int iteration_count;
@@ -712,39 +708,38 @@ static int is_complete(struct loopback_test *t)
 
 static int wait_for_complete(struct loopback_test *t)
 {
-	int remaining_timeouts = MAX_TIMEOUT_COUNT;
-	char buf[MAX_SYSFS_PATH];
-	struct timeval timeout;
-	fd_set read_fds;
+	int number_of_events = 0;
+	char dummy;
 	int ret;
+	int i;
 
 	while (1) {
-		/* Wait for change */
-		timeout.tv_sec = TIMEOUT_SEC;
-		timeout.tv_usec = 0;
-		FD_ZERO(&read_fds);
-		FD_SET(t->inotify_fd, &read_fds);
-		ret = select(FD_SETSIZE, &read_fds, NULL, NULL, &timeout);
-		if (ret < 0) {
-			fprintf(stderr, "Select error.\n");
+		ret = poll(t->fds, t->poll_count, DEFAULT_POLL_TIMEOUT_SEC * 1000);
+		if (ret == 0) {
+			fprintf(stderr, "Poll timmed out!\n");
 			return -1;
 		}
 
-		/* timeout - test may be finished.*/
-		if (!FD_ISSET(t->inotify_fd, &read_fds)) {
-			remaining_timeouts--;
-
-			if (is_complete(t))
-				return 0;
+		if (ret < 0) {
+			fprintf(stderr, "Poll Error!\n");
+			return -1;
+		}
 
-			if (!remaining_timeouts) {
-				fprintf(stderr, "Too many timeouts\n");
-				return -1;
+		for (i = 0; i < t->poll_count; i++) {
+			if (t->fds[i].revents & POLLPRI) {
+				/* Dummy read to clear the event */
+				read(t->fds[i].fd, &dummy, 1);
+				number_of_events++;
 			}
-		} else {
-			/* read to clear the event */
-			ret = read(t->inotify_fd, buf, sizeof(buf));
 		}
+
+		if (number_of_events == t->poll_count)
+			break;
+	}
+
+	if (!is_complete(t)) {
+		fprintf(stderr, "Iteration count did not finish!\n");
+		return -1;
 	}
 
 	return 0;
@@ -820,17 +815,17 @@ void loopback_run(struct loopback_test *t)
 
 	prepare_devices(t);
 
-	ret = register_for_notification(t);
+	ret = open_poll_files(t);
 	if (ret)
 		goto err;
 
 	start(t);
 
-	sleep(1);
-
-	wait_for_complete(t);
+	ret = wait_for_complete(t);
+	close_poll_files(t);
+	if (ret)
+		goto err;
 
-	unregister_for_notification(t);
 
 	get_results(t);
 
@@ -875,7 +870,7 @@ int main(int argc, char *argv[])
 	memset(&t, 0, sizeof(t));
 
 	while ((o = getopt(argc, argv,
-			   "t:s:i:S:D:m:v::d::r::p::a::l::x::o:c:w:")) != -1) {
+			   "t:s:i:S:D:m:v::d::r::p::a::l::x::o:c:w:O:")) != -1) {
 		switch (o) {
 		case 't':
 			snprintf(t.test_name, MAX_STR_LEN, "%s", optarg);
@@ -919,6 +914,9 @@ int main(int argc, char *argv[])
 		case 'o':
 			t.async_timeout = atoi(optarg);
 			break;
+		case 'O':
+			t.poll_timeout = atoi(optarg);
+			break;
 		case 'c':
 			t.async_outstanding_operations = atoi(optarg);
 			break;
@@ -957,6 +955,9 @@ int main(int argc, char *argv[])
 	if (t.async_timeout == 0)
 		t.async_timeout = DEFAULT_ASYNC_TIMEOUT;
 
+	if (t.poll_timeout == 0)
+		t.poll_timeout = DEFAULT_POLL_TIMEOUT_SEC;
+
 	loopback_run(&t);
 
 	return 0;