dmaengine: idxd: fix wq settings post wq disable

By the spec, wq size and group association is not changeable unless device
is disabled. Exclude clearing the shadow copy on wq disable/reset. This
allows wq type to be changed after disable to be re-enabled.

Move the size and group association to its own cleanup and only call it
during device disable.

Fixes: 0dcfe41e9a ("dmanegine: idxd: cleanup all device related bits after disabling device")
Reported-by: Lucas Van <lucas.van@intel.com>
Tested-by: Lucas Van <lucas.van@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163951291732.2987775.13576571320501115257.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/idxd/device.c

@@ -358,8 +358,6 @@ static void idxd_wq_disable_cleanup(struct idxd_wq *wq)
 	lockdep_assert_held(&wq->wq_lock);
 	memset(wq->wqcfg, 0, idxd->wqcfg_size);
 	wq->type = IDXD_WQT_NONE;
-	wq->size = 0;
-	wq->group = NULL;
 	wq->threshold = 0;
 	wq->priority = 0;
 	wq->ats_dis = 0;
@@ -371,6 +369,15 @@ static void idxd_wq_disable_cleanup(struct idxd_wq *wq)
 	wq->max_batch_size = WQ_DEFAULT_MAX_BATCH;
 }
 
+static void idxd_wq_device_reset_cleanup(struct idxd_wq *wq)
+{
+	lockdep_assert_held(&wq->wq_lock);
+
+	idxd_wq_disable_cleanup(wq);
+	wq->size = 0;
+	wq->group = NULL;
+}
+
 static void idxd_wq_ref_release(struct percpu_ref *ref)
 {
 	struct idxd_wq *wq = container_of(ref, struct idxd_wq, wq_active);
@@ -689,6 +696,7 @@ static void idxd_device_wqs_clear_state(struct idxd_device *idxd)
 
 		if (wq->state == IDXD_WQ_ENABLED) {
 			idxd_wq_disable_cleanup(wq);
+			idxd_wq_device_reset_cleanup(wq);
 			wq->state = IDXD_WQ_DISABLED;
 		}
 	}