[SCSI] fix scsi_reap_target() device_del from atomic context

scsi_reap_target() was desgined to be called from any context.
However it must do a device_del() of the target device, which may only
be called from user context.  Thus we have to reimplement
scsi_reap_target() via a workqueue.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 94e5167f260dbc93642b554ac2378cbc5f546908..e36c21e06d31e7b40e2599992082f98492c72c9b 100644 (file)
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -400,6 +400,35 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,
        return found_target;
 }
 
+struct work_queue_wrapper {
+       struct work_struct      work;
+       struct scsi_target      *starget;
+};
+
+static void scsi_target_reap_work(void *data) {
+       struct work_queue_wrapper *wqw = (struct work_queue_wrapper *)data;
+       struct scsi_target *starget = wqw->starget;
+       struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
+       unsigned long flags;
+
+       kfree(wqw);
+
+       spin_lock_irqsave(shost->host_lock, flags);
+
+       if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
+               list_del_init(&starget->siblings);
+               spin_unlock_irqrestore(shost->host_lock, flags);
+               device_del(&starget->dev);
+               transport_unregister_device(&starget->dev);
+               put_device(&starget->dev);
+               return;
+
+       }
+       spin_unlock_irqrestore(shost->host_lock, flags);
+
+       return;
+}
+
 /**
  * scsi_target_reap - check to see if target is in use and destroy if not
  *
@@ -411,19 +440,18 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,
  */
 void scsi_target_reap(struct scsi_target *starget)
 {
-       struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
-       unsigned long flags;
-       spin_lock_irqsave(shost->host_lock, flags);
+       struct work_queue_wrapper *wqw = 
+               kzalloc(sizeof(struct work_queue_wrapper), GFP_ATOMIC);
 
-       if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
-               list_del_init(&starget->siblings);
-               spin_unlock_irqrestore(shost->host_lock, flags);
-               device_del(&starget->dev);
-               transport_unregister_device(&starget->dev);
-               put_device(&starget->dev);
+       if (!wqw) {
+               starget_printk(KERN_ERR, starget,
+                              "Failed to allocate memory in scsi_reap_target()\n");
                return;
        }
-       spin_unlock_irqrestore(shost->host_lock, flags);
+
+       INIT_WORK(&wqw->work, scsi_target_reap_work, wqw);
+       wqw->starget = starget;
+       schedule_work(&wqw->work);
 }
 
 /**