From 673514aff5d797b0cdb3f09097ae0e253b5667c3 Mon Sep 17 00:00:00 2001 From: Stefan Haberland Date: Tue, 12 Sep 2017 17:22:42 +0200 Subject: [PATCH] s390/dasd: fix race during dasd initialization 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 Signed-off-by: Martin Schwidefsky --- 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);