If a worker requeues itself, it may switch to a different kworker pool, which flush_work() considers as complete. To be strict, we then need to keep flushing the work until it is no longer pending.
References: https://bugs.freedesktop.org/show_bug.cgi?id=102456 Signed-off-by: Chris Wilson <[email protected]> Cc: Mika Kuoppala <[email protected]> --- drivers/gpu/drm/i915/i915_debugfs.c | 3 +-- drivers/gpu/drm/i915/i915_gem.c | 3 +-- drivers/gpu/drm/i915/i915_utils.h | 13 +++++++++++++ 3 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 6338018f655d..d65558f650d6 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -4256,8 +4256,7 @@ fault_irq_set(struct drm_i915_private *i915, mutex_unlock(&i915->drm.struct_mutex); /* Flush idle worker to disarm irq */ - while (flush_delayed_work(&i915->gt.idle_work)) - ; + drain_delayed_work(&i915->gt.idle_work); return 0; diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index f445587c1a4b..d98f7b25d395 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -4583,8 +4583,7 @@ int i915_gem_suspend(struct drm_i915_private *dev_priv) /* As the idle_work is rearming if it detects a race, play safe and * repeat the flush until it is definitely idle. */ - while (flush_delayed_work(&dev_priv->gt.idle_work)) - ; + drain_delayed_work(&dev_priv->gt.idle_work); /* Assert that we sucessfully flushed all the work and * reset the GPU back to its idle, low power state. diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index 12fc250b47b9..4f7ffa0976b1 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -119,4 +119,17 @@ static inline void __list_del_many(struct list_head *head, WRITE_ONCE(head->next, first); } +/* + * Wait until the work is finally complete, even if it tries to postpone + * by requeueing itself. Note, that if the worker never cancels itself, + * we will spin forever. + */ +static inline void drain_delayed_work(struct delayed_work *dw) +{ + do { + while (flush_delayed_work(dw)) + ; + } while (delayed_work_pending(dw)); +} + #endif /* !__I915_UTILS_H */ -- 2.14.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
