uml: handle block device hotplug errors
If a disk fails to open, i.e. its host file doesn't exist, it won't be
removable because the hot-unplug code checks the existence of its gendisk.
This won't exist because it is only allocated for successfully opened disks.
Thus, a typo on the command line can result in a unusable and unfixable disk.
This is fixed by freeing the gendisk if it's there, but not letting that
affect the removal.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 8bd9204..53c36d1 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -788,14 +788,12 @@
static int ubd_remove(int n, char **error_out)
{
+ struct gendisk *disk;
struct ubd *ubd_dev;
int err = -ENODEV;
mutex_lock(&ubd_lock);
- if(ubd_gendisk[n] == NULL)
- goto out;
-
ubd_dev = &ubd_devs[n];
if(ubd_dev->file == NULL)
@@ -806,9 +804,12 @@
if(ubd_dev->count > 0)
goto out;
- del_gendisk(ubd_gendisk[n]);
- put_disk(ubd_gendisk[n]);
- ubd_gendisk[n] = NULL;
+ disk = ubd_gendisk[n];
+ ubd_gendisk[n] = NULL;
+ if(disk != NULL){
+ del_gendisk(disk);
+ put_disk(disk);
+ }
if(fake_gendisk[n] != NULL){
del_gendisk(fake_gendisk[n]);