[PATCH v2] Revert "nfsrahead: enable event-driven mountinfo monitoring"

[Steve Dickson <steved@redhat.com>]

This reverts commit 2b62ac4c273a647df07400dc1126fceb76ad96c0.

Most blktests block/ failed with "Timed out while waiting for
udev queue to empty." [1]

[1] https://lore.kernel.org/linux-block/CAHj4cs8URj2fJ7KyP9ViAm6npVOaMiAErnw2uFyPYEU2wb7G_w@mail.gmail.com/T/#t
---
 tools/nfsrahead/main.c | 35 +----------------------------------
 1 file changed, 1 insertion(+), 34 deletions(-)

diff --git a/tools/nfsrahead/main.c b/tools/nfsrahead/main.c
index 64953346..b7b889ff 100644
--- a/tools/nfsrahead/main.c
+++ b/tools/nfsrahead/main.c
@@ -16,7 +16,6 @@
 
 #define CONF_NAME "nfsrahead"
 #define NFS_DEFAULT_READAHEAD 128
-#define MNT_NM_TIMEOUT 10000
 
 /* Device information from the system */
 struct device_info {
@@ -118,39 +117,7 @@ out_free_device_info:
 
 static int get_device_info(const char *device_number, struct device_info *device_info)
 {
-	int ret;
-	struct libmnt_monitor *mn = NULL;
-	int timeout_ms = MNT_NM_TIMEOUT;
-
-	ret = get_mountinfo(device_number, device_info, MOUNTINFO_PATH);
-	if (ret == 0)
-		return 0;
-
-	mn = mnt_new_monitor();
-	if (!mn)
-		goto fallback;
-
-	if (mnt_monitor_enable_kernel(mn, 1) < 0) {
-		mnt_unref_monitor(mn);
-		goto fallback;
-	}
-
-	while (timeout_ms > 0) {
-		int rc = mnt_monitor_wait(mn, timeout_ms);
-		if (rc > 0) {
-			ret = get_mountinfo(device_number, device_info, MOUNTINFO_PATH);
-			if (ret == 0) {
-				mnt_unref_monitor(mn);
-				return 0;
-			}
-		} else {
-			break;
-		}
-	}
-	mnt_unref_monitor(mn);
-	return ret;
-
-fallback:
+	int ret = get_mountinfo(device_number, device_info, MOUNTINFO_PATH);
 	for (int retry_count = 0; retry_count < 5 && ret != 0; retry_count++) {
 		usleep(50000);
 		ret = get_mountinfo(device_number, device_info, MOUNTINFO_PATH);
-- 
2.53.0