drm/i915/gt: Pull checking rps->pm_events under the irq_lock
Avoid angering kcsan by serialising the read of the pm_events with the write in rps_disable_interrupts. [ 6268.713419] BUG: KCSAN: data-race in intel_rps_park [i915] / rps_work [i915] [ 6268.713437] [ 6268.713449] write to 0xffff8881eda8efac of 4 bytes by task 1127 on cpu 3: [ 6268.713680] intel_rps_park+0x136/0x260 [i915] [ 6268.713905] __gt_park+0x61/0xa0 [i915] [ 6268.714128] ____intel_wakeref_put_last+0x42/0x90 [i915] [ 6268.714352] __intel_wakeref_put_work+0xd3/0xf0 [i915] [ 6268.714369] process_one_work+0x3b1/0x690 [ 6268.714384] worker_thread+0x80/0x670 [ 6268.714398] kthread+0x19a/0x1e0 [ 6268.714412] ret_from_fork+0x1f/0x30 [ 6268.714423] [ 6268.714435] read to 0xffff8881eda8efac of 4 bytes by task 950 on cpu 2: [ 6268.714664] rps_work+0xc2/0x680 [i915] [ 6268.714679] process_one_work+0x3b1/0x690 [ 6268.714693] worker_thread+0x80/0x670 [ 6268.714707] kthread+0x19a/0x1e0 [ 6268.714720] ret_from_fork+0x1f/0x30 v2: Mark all reads and writes of rpm->pm_events. The flow of enabling/disabling rps is stronly ordered, so the writes and interrupt generation are also strongly ordered -- just this may not be visible to the compiler, so provide annotations. Signed-off-by:Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:
Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200311092624.10012-1-chris@chris-wilson.co.uk
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