drm/i915: Split I915_RESET_IN_PROGRESS into two flags

I915_RESET_IN_PROGRESS is being used for both signaling the requirement
to i915_mutex_lock_interruptible() to avoid taking the struct_mutex and
to instruct a waiter (already holding the struct_mutex) to perform the
reset. To allow for a little more coordination, split these two meaning
into a couple of distinct flags. I915_RESET_BACKOFF tells
i915_mutex_lock_interruptible() not to acquire the mutex and
I915_RESET_HANDOFF tells the waiter to call i915_reset().

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170316171305.12972-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 505c402..d62cf2e 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1305,16 +1305,18 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused)
 	enum intel_engine_id id;
 
 	if (test_bit(I915_WEDGED, &dev_priv->gpu_error.flags))
-		seq_printf(m, "Wedged\n");
-	if (test_bit(I915_RESET_IN_PROGRESS, &dev_priv->gpu_error.flags))
-		seq_printf(m, "Reset in progress\n");
+		seq_puts(m, "Wedged\n");
+	if (test_bit(I915_RESET_BACKOFF, &dev_priv->gpu_error.flags))
+		seq_puts(m, "Reset in progress: struct_mutex backoff\n");
+	if (test_bit(I915_RESET_HANDOFF, &dev_priv->gpu_error.flags))
+		seq_puts(m, "Reset in progress: reset handoff to waiter\n");
 	if (waitqueue_active(&dev_priv->gpu_error.wait_queue))
-		seq_printf(m, "Waiter holding struct mutex\n");
+		seq_puts(m, "Waiter holding struct mutex\n");
 	if (waitqueue_active(&dev_priv->gpu_error.reset_queue))
-		seq_printf(m, "struct_mutex blocked for reset\n");
+		seq_puts(m, "struct_mutex blocked for reset\n");
 
 	if (!i915.enable_hangcheck) {
-		seq_printf(m, "Hangcheck disabled\n");
+		seq_puts(m, "Hangcheck disabled\n");
 		return 0;
 	}
 
@@ -4127,7 +4129,7 @@ i915_wedged_set(void *data, u64 val)
 	 * while it is writing to 'i915_wedged'
 	 */
 
-	if (i915_reset_in_progress(&dev_priv->gpu_error))
+	if (i915_reset_backoff(&dev_priv->gpu_error))
 		return -EAGAIN;
 
 	i915_handle_error(dev_priv, val,