[PATCH 2/3] drm/xe: share bo dma-resv with backup object

[Matthew Auld <matthew.auld@intel.com>]

We end up needing to grab both locks together anyway and keep them held
until we complete the copy or add the fence. Plus the backup_obj is
short lived and tied to the parent object, so seems reasonable to share
the same dma-resv. This will simplify the locking here, and in follow
up patches.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/xe/xe_bo.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index c337790c81ae..3eab6352d9dc 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -1120,9 +1120,10 @@ int xe_bo_evict_pinned(struct xe_bo *bo)
 	if (bo->flags & XE_BO_FLAG_PINNED_NORESTORE)
 		goto out_unlock_bo;
 
-	backup = xe_bo_create_locked(xe, NULL, NULL, bo->size, ttm_bo_type_kernel,
-				     XE_BO_FLAG_SYSTEM | XE_BO_FLAG_NEEDS_CPU_ACCESS |
-				     XE_BO_FLAG_PINNED);
+	backup = ___xe_bo_create_locked(xe, NULL, NULL, bo->ttm.base.resv, NULL, bo->size,
+					DRM_XE_GEM_CPU_CACHING_WB, ttm_bo_type_kernel,
+					XE_BO_FLAG_SYSTEM | XE_BO_FLAG_NEEDS_CPU_ACCESS |
+					XE_BO_FLAG_PINNED);
 	if (IS_ERR(backup)) {
 		ret = PTR_ERR(backup);
 		goto out_unlock_bo;
@@ -1177,7 +1178,6 @@ int xe_bo_evict_pinned(struct xe_bo *bo)
 
 out_backup:
 	xe_bo_vunmap(backup);
-	xe_bo_unlock(backup);
 	if (ret)
 		xe_bo_put(backup);
 out_unlock_bo:
@@ -1212,17 +1212,12 @@ int xe_bo_restore_pinned(struct xe_bo *bo)
 	if (!backup)
 		return 0;
 
-	xe_bo_lock(backup, false);
+	xe_bo_lock(bo, false);
 
 	ret = ttm_bo_validate(&backup->ttm, &backup->placement, &ctx);
 	if (ret)
 		goto out_backup;
 
-	if (WARN_ON(!dma_resv_trylock(bo->ttm.base.resv))) {
-		ret = -EBUSY;
-		goto out_backup;
-	}
-
 	if (xe_bo_is_user(bo) || (bo->flags & XE_BO_FLAG_PINNED_LATE_RESTORE)) {
 		struct xe_migrate *migrate;
 		struct dma_fence *fence;
@@ -1271,15 +1266,14 @@ int xe_bo_restore_pinned(struct xe_bo *bo)
 
 	bo->backup_obj = NULL;
 
+out_backup:
+	xe_bo_vunmap(backup);
+	if (!bo->backup_obj)
+		xe_bo_put(backup);
 out_unlock_bo:
 	if (unmap)
 		xe_bo_vunmap(bo);
 	xe_bo_unlock(bo);
-out_backup:
-	xe_bo_vunmap(backup);
-	xe_bo_unlock(backup);
-	if (!bo->backup_obj)
-		xe_bo_put(backup);
 	return ret;
 }
 
-- 
2.49.0