nvme/pci: Don't free queues on error

commit d4875622 upstream.

The nvme_remove function tears down all allocated resources in the correct
order, so no need to free queues on error during initialization. This
fixes possible use-after-free errors when queues are still associated
with a blk-mq hctx.
Reported-by: Scott Bauer <scott.bauer@intel.com>
Tested-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimbeg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
[bwh: Backported to 3.16:
 - Adjust filename, context
 - Only nvme_setup_io_queues() needs to be fixed]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/block/nvme-core.c

@@ -2196,7 +2196,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	result = queue_request_irq(dev, adminq, adminq->irqname);
 	if (result) {
 		adminq->q_suspended = 1;
-		goto free_queues;
+		return result;
 	}
 
 	/* Free previously allocated queues that are no longer usable */
@@ -2204,10 +2204,6 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	nvme_assign_io_queues(dev);
 
 	return 0;
-
- free_queues:
-	nvme_free_queues(dev, 1);
-	return result;
 }
 
 /*