drm/i915: Allow for different modes of interruptible i915_active_wait

Allow some users the discretion to not immediately return on a normal
signal. Hopefully, they will opt to use TASK_KILLABLE instead.
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/20200327112212.16046-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_active.c

@@ -496,7 +496,7 @@ static int flush_lazy_signals(struct i915_active *ref)
 	return err;
 }
 
-int i915_active_wait(struct i915_active *ref)
+int __i915_active_wait(struct i915_active *ref, int state)
 {
 	int err;
 
@@ -511,7 +511,9 @@ int i915_active_wait(struct i915_active *ref)
 	if (err)
 		return err;
 
-	if (wait_var_event_interruptible(ref, i915_active_is_idle(ref)))
+	if (!i915_active_is_idle(ref) &&
+	    ___wait_var_event(ref, i915_active_is_idle(ref),
+			      state, 0, 0, schedule()))
 		return -EINTR;
 
 	flush_work(&ref->work);

drivers/gpu/drm/i915/i915_active.h

@@ -181,7 +181,11 @@ static inline bool i915_active_has_exclusive(struct i915_active *ref)
 	return rcu_access_pointer(ref->excl.fence);
 }
 
-int i915_active_wait(struct i915_active *ref);
+int __i915_active_wait(struct i915_active *ref, int state);
+static inline int i915_active_wait(struct i915_active *ref)
+{
+	return __i915_active_wait(ref, TASK_INTERRUPTIBLE);
+}
 
 int i915_sw_fence_await_active(struct i915_sw_fence *fence,
 			       struct i915_active *ref,

drivers/gpu/drm/i915/selftests/i915_active.c

@@ -153,7 +153,7 @@ static int live_active_wait(void *arg)
 	if (IS_ERR(active))
 		return PTR_ERR(active);
 
-	i915_active_wait(&active->base);
+	__i915_active_wait(&active->base, TASK_UNINTERRUPTIBLE);
 	if (!READ_ONCE(active->retired)) {
 		struct drm_printer p = drm_err_printer(__func__);
 
@@ -228,11 +228,11 @@ static int live_active_barrier(void *arg)
 	}
 
 	i915_active_release(&active->base);
+	if (err)
+		goto out;
 
-	if (err == 0)
-		err = i915_active_wait(&active->base);
-
-	if (err == 0 && !READ_ONCE(active->retired)) {
+	__i915_active_wait(&active->base, TASK_UNINTERRUPTIBLE);
+	if (!READ_ONCE(active->retired)) {
 		pr_err("i915_active not retired after flushing barriers!\n");
 		err = -EINVAL;
 	}