drm/xe: Don't grab runtime PM ref in engine create IOCTL

A VM had a runtime PM ref, a engine can't be created without a VM, and
the engine holds a ref to the VM thus this is unnecessary. Beyond that
taking a ref in the engine create IOCTL and dropping it in the destroy
IOCTL is wrong as a user doesn't have to call the destroy IOCTL (e.g.
they can just kill the process or close the driver FD). If a user does
this PM refs are leaked.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_engine.c b/drivers/gpu/drm/xe/xe_engine.c
index 141cb22..5666c8e 100644 (file)
--- a/drivers/gpu/drm/xe/xe_engine.c
+++ b/drivers/gpu/drm/xe/xe_engine.c
@@ -539,8 +539,6 @@ int xe_engine_create_ioctl(struct drm_device *dev, void *data,
        if (XE_IOCTL_ERR(xe, eci[0].gt_id >= xe->info.tile_count))
               return -EINVAL;
 
-       xe_pm_runtime_get(xe);
-
        if (eci[0].engine_class == DRM_XE_ENGINE_CLASS_VM_BIND) {
                for_each_gt(gt, xe, id) {
                        struct xe_engine *new;
@@ -552,16 +550,12 @@ int xe_engine_create_ioctl(struct drm_device *dev, void *data,
                        logical_mask = bind_engine_logical_mask(xe, gt, eci,
                                                                args->width,
                                                                args->num_placements);
-                       if (XE_IOCTL_ERR(xe, !logical_mask)) {
-                               err = -EINVAL;
-                               goto put_rpm;
-                       }
+                       if (XE_IOCTL_ERR(xe, !logical_mask))
+                               return -EINVAL;
 
                        hwe = find_hw_engine(xe, eci[0]);
-                       if (XE_IOCTL_ERR(xe, !hwe)) {
-                               err = -EINVAL;
-                               goto put_rpm;
-                       }
+                       if (XE_IOCTL_ERR(xe, !hwe))
+                               return -EINVAL;
 
                        migrate_vm = xe_migrate_get_vm(gt->migrate);
                        new = xe_engine_create(xe, migrate_vm, logical_mask,
@@ -576,7 +570,7 @@ int xe_engine_create_ioctl(struct drm_device *dev, void *data,
                                err = PTR_ERR(new);
                                if (e)
                                        goto put_engine;
-                               goto put_rpm;
+                               return err;
                        }
                        if (id == 0)
                                e = new;
@@ -589,30 +583,22 @@ int xe_engine_create_ioctl(struct drm_device *dev, void *data,
                logical_mask = calc_validate_logical_mask(xe, gt, eci,
                                                          args->width,
                                                          args->num_placements);
-               if (XE_IOCTL_ERR(xe, !logical_mask)) {
-                       err = -EINVAL;
-                       goto put_rpm;
-               }
+               if (XE_IOCTL_ERR(xe, !logical_mask))
+                       return -EINVAL;
 
                hwe = find_hw_engine(xe, eci[0]);
-               if (XE_IOCTL_ERR(xe, !hwe)) {
-                       err = -EINVAL;
-                       goto put_rpm;
-               }
+               if (XE_IOCTL_ERR(xe, !hwe))
+                       return -EINVAL;
 
                vm = xe_vm_lookup(xef, args->vm_id);
-               if (XE_IOCTL_ERR(xe, !vm)) {
-                       err = -ENOENT;
-                       goto put_rpm;
-               }
+               if (XE_IOCTL_ERR(xe, !vm))
+                       return -ENOENT;
 
                e = xe_engine_create(xe, vm, logical_mask,
                                     args->width, hwe, ENGINE_FLAG_PERSISTENT);
                xe_vm_put(vm);
-               if (IS_ERR(e)) {
-                       err = PTR_ERR(e);
-                       goto put_rpm;
-               }
+               if (IS_ERR(e))
+                       return PTR_ERR(e);
        }
 
        if (args->extensions) {
@@ -642,8 +628,6 @@ int xe_engine_create_ioctl(struct drm_device *dev, void *data,
 put_engine:
        xe_engine_kill(e);
        xe_engine_put(e);
-put_rpm:
-       xe_pm_runtime_put(xe);
        return err;
 }
 
@@ -750,7 +734,6 @@ int xe_engine_destroy_ioctl(struct drm_device *dev, void *data,
 
        trace_xe_engine_close(e);
        xe_engine_put(e);
-       xe_pm_runtime_put(xe);
 
        return 0;
 }