cciss: Use one scan thread per controller and fix hang during rmmod

Replace the use of one scan kthread per controller with one per driver.
Use a queue to hold a list of controllers that need to be rescanned with
routines to add and remove controllers from the queue.

Fix locking and completion handling to prevent a hang during rmmod.

Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Acked-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/block/cciss.h b/drivers/block/cciss.h
index 06a5db25b298..4fb3639b6cff 100644
--- a/drivers/block/cciss.h
+++ b/drivers/block/cciss.h
@@ -2,6 +2,7 @@
 #define CCISS_H
 
 #include <linux/genhd.h>
+#include <linux/mutex.h>
 
 #include "cciss_cmd.h"
 
@@ -108,6 +109,8 @@ struct ctlr_info
         int                     nr_frees; 
         int                     busy_configuring;
         int                     busy_initializing;
+        int                     busy_scanning;
+        struct mutex            busy_shutting_down;
 
         /* This element holds the zero based queue number of the last
          * queue to be started.  It is used for fairness.
@@ -122,8 +125,8 @@ struct ctlr_info
         /* and saved for later processing */
 #endif
         unsigned char alive;
-        struct completion *rescan_wait;
-        struct task_struct *cciss_scan_thread;
+        struct list_head scan_list;
+        struct completion scan_wait;
         struct device dev;
 };