drm/i915/gem: Drop forced struct_mutex from shrinker_taints_mutex

Since we no longer always take struct_mutex around everything, and want
the freedom to create GEM objects, actually taking struct_mutex inside
the lock creation ends up pulling the mutex inside other looks. Since we
don't use generally use struct_mutex, we can relax the tainting.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200702083225.20044-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/i915_gem_shrinker.c

@@ -408,26 +408,15 @@ void i915_gem_driver_unregister__shrinker(struct drm_i915_private *i915)
 void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915,
 				    struct mutex *mutex)
 {
-	bool unlock = false;
-
 	if (!IS_ENABLED(CONFIG_LOCKDEP))
 		return;
 
-	if (!lockdep_is_held_type(&i915->drm.struct_mutex, -1)) {
-		mutex_acquire(&i915->drm.struct_mutex.dep_map,
-			      I915_MM_NORMAL, 0, _RET_IP_);
-		unlock = true;
-	}
-
 	fs_reclaim_acquire(GFP_KERNEL);
 
 	mutex_acquire(&mutex->dep_map, 0, 0, _RET_IP_);
 	mutex_release(&mutex->dep_map, _RET_IP_);
 
 	fs_reclaim_release(GFP_KERNEL);
-
-	if (unlock)
-		mutex_release(&i915->drm.struct_mutex.dep_map, _RET_IP_);
 }
 
 #define obj_to_i915(obj__) to_i915((obj__)->base.dev)