We only need to take the struct_mutex if the object is pinned to the
display engine and so requires checking for clflush. (The race with
userspace pinning the object to a framebuffer is irrelevant.)

v2: Use access once for compiler hints (or not as it is a bitfield)

Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a4f949038d50..b78f9df1894c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1265,25 +1265,28 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void 
*data,
 {
        struct drm_i915_gem_sw_finish *args = data;
        struct drm_i915_gem_object *obj;
-       int ret = 0;
-
-       ret = i915_mutex_lock_interruptible(dev);
-       if (ret)
-               return ret;
+       int ret;
 
        obj = i915_gem_object_lookup(file, args->handle);
-       if (!obj) {
-               ret = -ENOENT;
-               goto unlock;
-       }
+       if (!obj)
+               return -ENOENT;
 
        /* Pinned buffers may be scanout, so flush the cache */
-       if (obj->pin_display)
+       if (obj->pin_display) {
+               ret = i915_mutex_lock_interruptible(dev);
+               if (ret)
+                       goto unref;
+
                i915_gem_object_flush_cpu_write_domain(obj);
 
-       i915_gem_object_put(obj);
-unlock:
-       mutex_unlock(&dev->struct_mutex);
+               i915_gem_object_put(obj);
+               mutex_unlock(&dev->struct_mutex);
+       } else {
+               ret = 0;
+unref:
+               i915_gem_object_put_unlocked(obj);
+       }
+
        return ret;
 }
 
-- 
2.8.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Reply via email to