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fa4d0f1992
With the current implementation the following race can happen: * blk_pre_runtime_suspend() calls blk_freeze_queue_start() and blk_mq_unfreeze_queue(). * blk_queue_enter() calls blk_queue_pm_only() and that function returns true. * blk_queue_enter() calls blk_pm_request_resume() and that function does not call pm_request_resume() because the queue runtime status is RPM_ACTIVE. * blk_pre_runtime_suspend() changes the queue status into RPM_SUSPENDING. Fix this race by changing the queue runtime status into RPM_SUSPENDING before switching q_usage_counter to atomic mode. Link: https://lore.kernel.org/r/20201209052951.16136-2-bvanassche@acm.org Fixes: 986d413b7c15 ("blk-mq: Enable support for runtime power management") Cc: Ming Lei <ming.lei@redhat.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: stable <stable@vger.kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Stanley Chu <stanley.chu@mediatek.com> Co-developed-by: Can Guo <cang@codeaurora.org> Signed-off-by: Can Guo <cang@codeaurora.org> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.