[PATCH 3/6] drm/i915: Convert i915_gem_object_attach_phys() to ww locking

[Maarten Lankhorst]

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_phys.c | 35 +++++++++++++++++-------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
index 28147aab47b9..3548267b8572 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
@@ -149,37 +149,46 @@ static const struct drm_i915_gem_object_ops i915_gem_phys_ops = {
 
 int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
 {
+	struct i915_gem_ww_ctx ww;
 	struct sg_table *pages;
 	int err;
 
 	if (align > obj->base.size)
 		return -EINVAL;
 
+	i915_gem_ww_ctx_init(&ww, true);
+retry:
+	err = i915_gem_object_lock(obj, &ww);
+	if (err)
+		goto out;
+
 	if (obj->ops == &i915_gem_phys_ops)
-		return 0;
+		goto out;
 
-	if (obj->ops != &i915_gem_shmem_ops)
-		return -EINVAL;
+	if (obj->ops != &i915_gem_shmem_ops) {
+		err = -EINVAL;
+		goto out;
+	}
 
 	err = i915_gem_object_unbind(obj, I915_GEM_OBJECT_UNBIND_ACTIVE);
 	if (err)
-		return err;
+		goto out;
 
 	mutex_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES);
 
 	if (obj->mm.madv != I915_MADV_WILLNEED) {
 		err = -EFAULT;
-		goto err_unlock;
+		goto out_unlock;
 	}
 
 	if (obj->mm.quirked) {
 		err = -EFAULT;
-		goto err_unlock;
+		goto out_unlock;
 	}
 
 	if (obj->mm.mapping) {
 		err = -EBUSY;
-		goto err_unlock;
+		goto out_unlock;
 	}
 
 	pages = __i915_gem_object_unset_pages(obj);
@@ -198,8 +207,7 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
 
 	i915_gem_object_release_memory_region(obj);
 
-	mutex_unlock(&obj->mm.lock);
-	return 0;
+	goto out_unlock;
 
 err_xfer:
 	obj->ops = &i915_gem_shmem_ops;
@@ -208,8 +216,15 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
 
 		__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
 	}
-err_unlock:
+out_unlock:
 	mutex_unlock(&obj->mm.lock);
+out:
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
 	return err;
 }
 
-- 
2.28.0