drm/i915: Markup paired operations on wakerefs
The majority of runtime-pm operations are bounded and scoped within a function; these are easy to verify that the wakeref are handled correctly. We can employ the compiler to help us, and reduce the number of wakerefs tracked when debugging, by passing around cookies provided by the various rpm_get functions to their rpm_put counterpart. This makes the pairing explicit, and given the required wakeref cookie the compiler can verify that we pass an initialised value to the rpm_put (quite handy for double checking error paths). For regular builds, the compiler should be able to eliminate the unused local variables and the program growth should be minimal. Fwiw, it came out as a net improvement as gcc was able to refactor rpm_get and rpm_get_if_in_use together, v2: Just s/rpm_put/rpm_put_unchecked/ everywhere, leaving the manual mark up for smaller more targeted patches. v3: Mention the cookie in Returns Signed-off-by:Chris Wilson <chris@chris-wilson.co.uk> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by:
Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-2-chris@chris-wilson.co.uk
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