The engine busyness stats has a worker function to do things like 64bit extend the 32bit hardware counters. The GuC's reset prepare function flushes out this worker function to ensure no corruption happens during the reset. Unforunately, the worker function has an infinite wait for active resets to finish before doing its work. Thus a deadlock would occur if the worker function had actually started just as the reset starts. The function being used to lock the reset-in-progress mutex is called intel_gt_reset_trylock(). However, as noted it does not follow standard 'trylock' conventions and exit if already locked. So rename the current _trylock function to intel_gt_reset_lock_interruptible(), which is the behaviour it actually provides. In addition, add a new implementation of _trylock and call that from the busyness stats worker instead. v2: Rename existing trylock to interruptible rather than trying to preserve the existing (confusing) naming scheme (review comments from Tvrtko). Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221102192109.2492625-3-John.C.Harrison@Intel.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.
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