cciss: Fix race between disk-adding code and interrupt handler
Fix race condition between cciss_init_one(), cciss_update_drive_info(),
and cciss_check_queues().
Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 9c9627e..cf6083a 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -1349,6 +1349,10 @@
spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
h->drv[drv_index].busy_configuring = 1;
spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+
+ /* deregister_disk sets h->drv[drv_index].queue = NULL */
+ /* which keeps the interrupt handler from starting */
+ /* the queue. */
ret = deregister_disk(h->gendisk[drv_index],
&h->drv[drv_index], 0);
h->drv[drv_index].busy_configuring = 0;
@@ -1419,6 +1423,10 @@
blk_queue_hardsect_size(disk->queue,
hba[ctlr]->drv[drv_index].block_size);
+ /* Make sure all queue data is written out before */
+ /* setting h->drv[drv_index].queue, as setting this */
+ /* allows the interrupt handler to start the queue */
+ wmb();
h->drv[drv_index].queue = disk->queue;
add_disk(disk);
}
@@ -3520,10 +3528,17 @@
continue;
blk_queue_hardsect_size(q, drv->block_size);
set_capacity(disk, drv->nr_blocks);
- add_disk(disk);
j++;
} while (j <= hba[i]->highest_lun);
+ /* Make sure all queue data is written out before */
+ /* interrupt handler, triggered by add_disk, */
+ /* is allowed to start them. */
+ wmb();
+
+ for (j = 0; j <= hba[i]->highest_lun; j++)
+ add_disk(hba[i]->gendisk[j]);
+
return 1;
clean4: