---

yaml
---
r: 172956
b: refs/heads/master
c: da00218
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d06dfbd236795acbb67e22e51bb8af12e953ced3
+refs/heads/master: da0021841c3ea6a82588efae3260015847ea5d33

trunk/drivers/block/cciss.c

@@ -3416,8 +3416,22 @@ static int check_for_unit_attention(ctlr_info_t *h, CommandList_struct *c)
 	case REPORT_LUNS_CHANGED:
 		printk(KERN_WARNING "cciss%d: report LUN data "
 			"changed\n", h->ctlr);
-		add_to_scan_list(h);
-		wake_up_process(cciss_scan_thread);
+	/*
+	 * Here, we could call add_to_scan_list and wake up the scan thread,
+	 * except that it's quite likely that we will get more than one
+	 * REPORT_LUNS_CHANGED condition in quick succession, which means
+	 * that those which occur after the first one will likely happen
+	 * *during* the scan_thread's rescan.  And the rescan code is not
+	 * robust enough to restart in the middle, undoing what it has already
+	 * done, and it's not clear that it's even possible to do this, since
+	 * part of what it does is notify the block layer, which starts
+	 * doing it's own i/o to read partition tables and so on, and the
+	 * driver doesn't have visibility to know what might need undoing.
+	 * In any event, if possible, it is horribly complicated to get right
+	 * so we just don't do it for now.
+	 *
+	 * Note: this REPORT_LUNS_CHANGED condition only occurs on the MSA2012.
+	 */
 		return 1;
 	break;
 	case POWER_OR_RESET: