[RFC PATCH 018/162] drm/i915: Convert i915_gem_object_attach_phys() to ww locking, v2.

[Matthew Auld]

From: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>

Simple adding of i915_gem_object_lock, we may start to pass ww to
get_pages() in the future, but that won't be the case here;
We override shmem's get_pages() handling by calling
i915_gem_object_get_pages_phys(), no ww is needed.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_object.h |  2 ++
 drivers/gpu/drm/i915/gem/i915_gem_phys.c   | 12 ++++++++++--
 drivers/gpu/drm/i915/gem/i915_gem_shmem.c  | 17 ++++++++++-------
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index e549b88693a2..47da3aff2a79 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -43,6 +43,8 @@ int i915_gem_object_pread_phys(struct drm_i915_gem_object *obj,
 			       const struct drm_i915_gem_pread *args);
 
 int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align);
+void i915_gem_object_put_pages_shmem(struct drm_i915_gem_object *obj,
+				     struct sg_table *pages);
 void i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
 				    struct sg_table *pages);
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
index 4bdd0429c08b..144e4940eede 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
@@ -201,7 +201,7 @@ static int i915_gem_object_shmem_to_phys(struct drm_i915_gem_object *obj)
 	__i915_gem_object_pin_pages(obj);
 
 	if (!IS_ERR_OR_NULL(pages))
-		i915_gem_shmem_ops.put_pages(obj, pages);
+		i915_gem_object_put_pages_shmem(obj, pages);
 
 	i915_gem_object_release_memory_region(obj);
 	return 0;
@@ -232,7 +232,13 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
 	if (err)
 		return err;
 
-	mutex_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+	err = i915_gem_object_lock_interruptible(obj, NULL);
+	if (err)
+		return err;
+
+	err = mutex_lock_interruptible_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+	if (err)
+		goto err_unlock;
 
 	if (unlikely(!i915_gem_object_has_struct_page(obj)))
 		goto out;
@@ -263,6 +269,8 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
 
 out:
 	mutex_unlock(&obj->mm.lock);
+err_unlock:
+	i915_gem_object_unlock(obj);
 	return err;
 }
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index d590e0c3bd00..7a59fd1ea4e5 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -296,18 +296,12 @@ __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
 	__start_cpu_write(obj);
 }
 
-static void
-shmem_put_pages(struct drm_i915_gem_object *obj, struct sg_table *pages)
+void i915_gem_object_put_pages_shmem(struct drm_i915_gem_object *obj, struct sg_table *pages)
 {
 	struct sgt_iter sgt_iter;
 	struct pagevec pvec;
 	struct page *page;
 
-	if (unlikely(!i915_gem_object_has_struct_page(obj))) {
-		i915_gem_object_put_pages_phys(obj, pages);
-		return;
-	}
-
 	__i915_gem_object_release_shmem(obj, pages, true);
 
 	i915_gem_gtt_finish_pages(obj, pages);
@@ -336,6 +330,15 @@ shmem_put_pages(struct drm_i915_gem_object *obj, struct sg_table *pages)
 	kfree(pages);
 }
 
+static void
+shmem_put_pages(struct drm_i915_gem_object *obj, struct sg_table *pages)
+{
+	if (likely(i915_gem_object_has_struct_page(obj)))
+		i915_gem_object_put_pages_shmem(obj, pages);
+	else
+		i915_gem_object_put_pages_phys(obj, pages);
+}
+
 static int
 shmem_pwrite(struct drm_i915_gem_object *obj,
 	     const struct drm_i915_gem_pwrite *arg)
-- 
2.26.2