1 files changed, 16 insertions, 2 deletions

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 42eaddb54380..bf2d1c80b788 100644
--- a/drivers/block/cciss.c
+++ b/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: