From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 19 Jan 2017 08:22:10 +0000 (+0000)
Subject: drm/i915: Do an unlocked wait before set-cache-level ioctl
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d65415df0708700e306fcbcaece23369de4cb74e;p=linux-beck.git

drm/i915: Do an unlocked wait before set-cache-level ioctl

Since a change in cache level is likely to trigger an unbind, avoid
waiting under the mutex by preemptively doing an unlocked wait.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170119082211.21257-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
---

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b2f8ac1386a2..4f23a8f4303e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3397,7 +3397,7 @@ int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
 	struct drm_i915_gem_caching *args = data;
 	struct drm_i915_gem_object *obj;
 	enum i915_cache_level level;
-	int ret;
+	int ret = 0;
 
 	switch (args->caching) {
 	case I915_CACHING_NONE:
@@ -3422,20 +3422,29 @@ int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
 		return -EINVAL;
 	}
 
-	ret = i915_mutex_lock_interruptible(dev);
+	obj = i915_gem_object_lookup(file, args->handle);
+	if (!obj)
+		return -ENOENT;
+
+	if (obj->cache_level == level)
+		goto out;
+
+	ret = i915_gem_object_wait(obj,
+				   I915_WAIT_INTERRUPTIBLE,
+				   MAX_SCHEDULE_TIMEOUT,
+				   to_rps_client(file));
 	if (ret)
-		return ret;
+		goto out;
 
-	obj = i915_gem_object_lookup(file, args->handle);
-	if (!obj) {
-		ret = -ENOENT;
-		goto unlock;
-	}
+	ret = i915_mutex_lock_interruptible(dev);
+	if (ret)
+		goto out;
 
 	ret = i915_gem_object_set_cache_level(obj, level);
-	i915_gem_object_put(obj);
-unlock:
 	mutex_unlock(&dev->struct_mutex);
+
+out:
+	i915_gem_object_put(obj);
 	return ret;
 }