From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Date: Thu, 21 Aug 2008 17:46:40 +0000 (+0200)
Subject: [S390] dcssblk: fix race in dcssblk_add_store()
X-Git-Tag: v2.6.27-rc5~57
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=04f64b5756872b474d9429e3b6987ada10bb8012;p=linux-2.6

[S390] dcssblk: fix race in dcssblk_add_store()

Concurrently adding the same segment may lead to duplicate device_register()
calls, which will trigger an error in kobject code:
"... don't try to register things with the same name in the same directory".
This patch adds a check to avoid this.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 01fcdd91b8..db85f1fb13 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -384,6 +384,10 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
 	 * get minor, add to list
 	 */
 	down_write(&dcssblk_devices_sem);
+	if (dcssblk_get_segment_by_name(local_buf)) {
+		rc = -EEXIST;
+		goto release_gd;
+	}
 	rc = dcssblk_assign_free_minor(dev_info);
 	if (rc) {
 		up_write(&dcssblk_devices_sem);