drm/i915: Mark intel_wakeref_get() as a sleeper

Assume that intel_wakeref_get() may take the mutex, and perform other
sleeping actions in the course of its callbacks and so use might_sleep()
to ensure that all callers abide. Anything that cannot sleep has to use
e.g. intel_wakeref_get_if_active() to guarantee its avoidance of the
non-atomic paths.

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/20191121130528.309474-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
index 990efc27a4e4b02a5cfd2c1e4f4f073661f70bb6..4a9e48c12bd4d3a0ddbc139d4e714c88eefaaaac 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
@@ -22,6 +22,11 @@ static inline void intel_gt_pm_get(struct intel_gt *gt)
        intel_wakeref_get(&gt->wakeref);
 }
 
+static inline void __intel_gt_pm_get(struct intel_gt *gt)
+{
+       __intel_wakeref_get(&gt->wakeref);
+}
+
 static inline bool intel_gt_pm_get_if_awake(struct intel_gt *gt)
 {
        return intel_wakeref_get_if_active(&gt->wakeref);

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index da72794f3707958660f71ede6adb37043d76577d..0e2065a13f24e304f760d811f682bb8fdf671fde 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1121,7 +1121,7 @@ __execlists_schedule_in(struct i915_request *rq)
                BUILD_BUG_ON(NUM_CONTEXT_TAG > GEN12_MAX_CONTEXT_HW_ID);
        }
 
-       intel_gt_pm_get(engine->gt);
+       __intel_gt_pm_get(engine->gt);
        execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
        intel_engine_context_in(engine);
 

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index dcccbd6408093df606c9d1f2486629f9a456729c..6f94af7ad1de24eb5a5ead7f703c42e7f3c8e67c 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -529,7 +529,7 @@ static struct i915_request *schedule_in(struct i915_request *rq, int idx)
         * required if we generalise the inflight tracking.
         */
 
-       intel_gt_pm_get(rq->engine->gt);
+       __intel_gt_pm_get(rq->engine->gt);
        return i915_request_get(rq);
 }
 

diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
index da6e8fd506e66f4057d376c1dc82412dd5323147..8d945db94b7ab63813813db35eca83e75822e648 100644 (file)
--- a/drivers/gpu/drm/i915/intel_wakeref.h
+++ b/drivers/gpu/drm/i915/intel_wakeref.h
@@ -59,9 +59,7 @@ void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags);
 
 /**
  * intel_wakeref_get: Acquire the wakeref
- * @i915: the drm_i915_private device
  * @wf: the wakeref
- * @fn: callback for acquired the wakeref, called only on first acquire.
  *
  * Acquire a hold on the wakeref. The first user to do so, will acquire
  * the runtime pm wakeref and then call the @fn underneath the wakeref
@@ -76,12 +74,29 @@ void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags);
 static inline int
 intel_wakeref_get(struct intel_wakeref *wf)
 {
+       might_sleep();
        if (unlikely(!atomic_inc_not_zero(&wf->count)))
                return __intel_wakeref_get_first(wf);
 
        return 0;
 }
 
+/**
+ * __intel_wakeref_get: Acquire the wakeref, again
+ * @wf: the wakeref
+ *
+ * Increment the wakeref counter, only valid if it is already held by
+ * the caller.
+ *
+ * See intel_wakeref_get().
+ */
+static inline void
+__intel_wakeref_get(struct intel_wakeref *wf)
+{
+       INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
+       atomic_inc(&wf->count);
+}
+
 /**
  * intel_wakeref_get_if_in_use: Acquire the wakeref
  * @wf: the wakeref