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[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>
This commit is contained in:
Stefan Weinhuber 2007-02-05 21:17:04 +01:00 committed by Martin Schwidefsky
parent dbd8ae6306
commit e3c699b38e
1 changed files with 17 additions and 7 deletions
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24
drivers/s390/block/dasd_eer.c
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@ -658,18 +658,24 @@ static struct file_operations dasd_eer_fops = {
.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;
}
}