[Intel-gfx] [PATCH 03/37] drm/i915: Defer acquiring mutex in intel_crtc_page_flip()

[Chris Wilson]

Reduce the amount of code under the spinlocks and mutex, and in
particular avoid the unnecessary nesting of the two.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
Cc: Kristian Høgsberg <krh at bitplanet.net>
---
 drivers/gpu/drm/i915/intel_display.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0e2c5da..979c628 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4225,8 +4225,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 	if (work == NULL)
 		return -ENOMEM;
 
-	mutex_lock(&dev->struct_mutex);
-
 	work->event = event;
 	work->dev = crtc->dev;
 	intel_fb = to_intel_framebuffer(crtc->fb);
@@ -4239,7 +4237,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 		DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
 		spin_unlock_irqrestore(&dev->event_lock, flags);
 		kfree(work);
-		mutex_unlock(&dev->struct_mutex);
 		return -EBUSY;
 	}
 	intel_crtc->unpin_work = work;
@@ -4248,13 +4245,18 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 	intel_fb = to_intel_framebuffer(fb);
 	obj = intel_fb->obj;
 
+	mutex_lock(&dev->struct_mutex);
 	ret = intel_pin_and_fence_fb_obj(dev, obj);
 	if (ret != 0) {
 		DRM_DEBUG_DRIVER("flip queue: %p pin & fence failed\n",
 			  obj->driver_private);
-		kfree(work);
-		intel_crtc->unpin_work = NULL;
 		mutex_unlock(&dev->struct_mutex);
+
+		spin_lock_irqsave(&dev->event_lock, flags);
+		intel_crtc->unpin_work = NULL;
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+
+		kfree(work);
 		return ret;
 	}
 
-- 
1.7.0