From 19153e3a65d0e5dd406d15de72fdbeb81fe04231 Mon Sep 17 00:00:00 2001
From: Vladislav Bolkhovitin <vst@vlnb.net>
Date: Fri, 24 Aug 2012 02:15:04 +0000
Subject: [PATCH] Ensure that generated USN is unique

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@4471 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 scst/src/dev_handlers/scst_vdisk.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/scst/src/dev_handlers/scst_vdisk.c b/scst/src/dev_handlers/scst_vdisk.c
index a559ffd33..d9c081dfa 100644
--- a/scst/src/dev_handlers/scst_vdisk.c
+++ b/scst/src/dev_handlers/scst_vdisk.c
@@ -4139,11 +4139,12 @@ out:
 	return res;
 }
 
+/* scst_vdisk_mutex supposed to be held */
 static int vdev_create(struct scst_dev_type *devt,
 	const char *name, struct scst_vdisk_dev **res_virt_dev)
 {
 	int res;
-	struct scst_vdisk_dev *virt_dev;
+	struct scst_vdisk_dev *virt_dev, *vv;
 	uint64_t dev_id_num;
 
 	res = -EEXIST;
@@ -4185,6 +4186,15 @@ static int vdev_create(struct scst_dev_type *devt,
 	scnprintf(virt_dev->usn, sizeof(virt_dev->usn), "%llx", dev_id_num);
 	TRACE_DBG("usn %s", virt_dev->usn);
 
+	list_for_each_entry(vv, &vdev_list, vdev_list_entry) {
+		if (strcmp(virt_dev->usn, vv->usn) == 0) {
+			PRINT_ERROR("New usn %s conflicts with one of dev %s",
+				virt_dev->usn, vv->name);
+			res = -EEXIST;
+			goto out_free;
+		}
+	}
+
 	*res_virt_dev = virt_dev;
 	res = 0;