From: Stefan Haberland <sth@linux.vnet.ibm.com>
Date: Tue, 12 Sep 2017 17:22:42 +0200
Subject: [PATCH] s390/dasd: fix race during dasd initialization
Git-commit: 673514aff5d797b0cdb3f09097ae0e253b5667c3
Patch-mainline: v4.14-rc2
References: bsc#1104967,FATE#325924
Fix a panic in blk_mq_hctx_has_pending() that is caused by a racy call to
blk_mq_run_hw_queues in a dasd function that might get called with the
request queue not yet initialized during initialization.
Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/s390/block/dasd.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index ea19b4ff87a2..29f35e29d480 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1644,7 +1644,9 @@ void dasd_generic_handle_state_change(struct dasd_device *device)
dasd_schedule_device_bh(device);
if (device->block) {
dasd_schedule_block_bh(device->block);
- blk_mq_run_hw_queues(device->block->request_queue, true);
+ if (device->block->request_queue)
+ blk_mq_run_hw_queues(device->block->request_queue,
+ true);
}
}
EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
@@ -3759,7 +3761,9 @@ int dasd_generic_path_operational(struct dasd_device *device)
dasd_schedule_device_bh(device);
if (device->block) {
dasd_schedule_block_bh(device->block);
- blk_mq_run_hw_queues(device->block->request_queue, true);
+ if (device->block->request_queue)
+ blk_mq_run_hw_queues(device->block->request_queue,
+ true);
}
if (!device->stopped)
@@ -4025,7 +4029,9 @@ int dasd_generic_restore_device(struct ccw_device *cdev)
if (device->block) {
dasd_schedule_block_bh(device->block);
- blk_mq_run_hw_queues(device->block->request_queue, true);
+ if (device->block->request_queue)
+ blk_mq_run_hw_queues(device->block->request_queue,
+ true);
}
clear_bit(DASD_FLAG_SUSPENDED, &device->flags);
--
2.16.4