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If the nvme driver is shutting down its controller, the drievr will not start the queues up again, preventing blk-mq's hot CPU notifier from making forward progress. To fix that, this patch starts a request_queue freeze when the driver resets a controller so no new requests may enter. The driver will wait for frozen after IO queues are restarted to ensure the queue reference can be reinitialized when nvme requests to unfreeze the queues. If the driver is doing a safe shutdown, the driver will wait for the controller to successfully complete all inflight requests so that we don't unnecessarily fail them. Once the controller has been disabled, the queues will be restarted to force remaining entered requests to end in failure so that blk-mq's hot cpu notifier may progress. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@fb.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.