From: Stefan Weinhuber <wein@de.ibm.com>
[S390] dasd: fix bug in dasd initialization cleanup
The initialization of the dasd_eer code is one of the last steps of the
dasd driver initialization. When initialization fails in one of the
earlier steps, the dasd_exit function is called to clean up what has been
done so far. So the dasd_eer_exit function may be called, although the
dasd_eer_init function wasn't called before and dasd_eer_exit tries to
unregister a misc device that wasn't registered, which results in a BUG.
Make sure that dasd_eer_exit can be called without initialization. Use a
dynamically allocated struct miscdevice instead of a static one, so we
only try to unregister the device if it exists and was actually registered.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
drivers/s390/block/dasd_eer.c | 24 +++++++++++++++++-------
1 files changed, 17 insertions(+), 7 deletions(-)
diff -urpN linux-2.6/drivers/s390/block/dasd_eer.c linux-2.6-patched/drivers/s390/block/dasd_eer.c
--- linux-2.6/drivers/s390/block/dasd_eer.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6-patched/drivers/s390/block/dasd_eer.c 2007-01-26 17:27:54.000000000 +0100
@@ -658,18 +658,24 @@ static struct file_operations dasd_eer_f
.owner = THIS_MODULE,
};
-static struct miscdevice dasd_eer_dev = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = "dasd_eer",
- .fops = &dasd_eer_fops,
-};
+static struct miscdevice *dasd_eer_dev = NULL;
int __init dasd_eer_init(void)
{
int rc;
- rc = misc_register(&dasd_eer_dev);
+ dasd_eer_dev = kzalloc(sizeof(*dasd_eer_dev), GFP_KERNEL);
+ if (!dasd_eer_dev)
+ return -ENOMEM;
+
+ dasd_eer_dev->minor = MISC_DYNAMIC_MINOR;
+ dasd_eer_dev->name = "dasd_eer";
+ dasd_eer_dev->fops = &dasd_eer_fops;
+
+ rc = misc_register(dasd_eer_dev);
if (rc) {
+ kfree(dasd_eer_dev);
+ dasd_eer_dev = NULL;
MESSAGE(KERN_ERR, "%s", "dasd_eer_init could not "
"register misc device");
return rc;
@@ -680,5 +686,9 @@ int __init dasd_eer_init(void)
void dasd_eer_exit(void)
{
- WARN_ON(misc_deregister(&dasd_eer_dev) != 0);
+ if (dasd_eer_dev) {
+ WARN_ON(misc_deregister(dasd_eer_dev) != 0);
+ kfree(dasd_eer_dev);
+ dasd_eer_dev = NULL;
+ }
}
-
