[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>

1 files changed, 38 insertions, 10 deletions

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 94e5167f260d..e36c21e06d31 100644
--- 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);
 }
 
 /**