[SCSI] fix oops on usb storage device disconnect
We fix the oops by enforcing the host state model. There have also
been two extra states added: SHOST_CANCEL_RECOVERY and
SHOST_DEL_RECOVERY so we can take the model through host removal while
the recovery thread is active.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 85503fa..f2a72d3 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -98,6 +98,7 @@
switch (oldstate) {
case SHOST_CREATED:
case SHOST_RUNNING:
+ case SHOST_CANCEL_RECOVERY:
break;
default:
goto illegal;
@@ -107,12 +108,31 @@
case SHOST_DEL:
switch (oldstate) {
case SHOST_CANCEL:
+ case SHOST_DEL_RECOVERY:
break;
default:
goto illegal;
}
break;
+ case SHOST_CANCEL_RECOVERY:
+ switch (oldstate) {
+ case SHOST_CANCEL:
+ case SHOST_RECOVERY:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
+
+ case SHOST_DEL_RECOVERY:
+ switch (oldstate) {
+ case SHOST_CANCEL_RECOVERY:
+ break;
+ default:
+ goto illegal;
+ }
+ break;
}
shost->shost_state = state;
return 0;
@@ -134,13 +154,24 @@
**/
void scsi_remove_host(struct Scsi_Host *shost)
{
+ unsigned long flags;
down(&shost->scan_mutex);
- scsi_host_set_state(shost, SHOST_CANCEL);
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_set_state(shost, SHOST_CANCEL))
+ if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ up(&shost->scan_mutex);
+ return;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
up(&shost->scan_mutex);
scsi_forget_host(shost);
scsi_proc_host_rm(shost);
- scsi_host_set_state(shost, SHOST_DEL);
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_set_state(shost, SHOST_DEL))
+ BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
+ spin_unlock_irqrestore(shost->host_lock, flags);
transport_unregister_device(&shost->shost_gendev);
class_device_unregister(&shost->shost_classdev);