dmaengine: idxd: create locked version of idxd_quiesce() call

Add a locked version of idxd_quiesce() call so that the quiesce can be
called with a lock in situations where the lock is not held by the caller.

In the driver probe/remove path, the lock is already held, so the raw
version can be called w/o locking.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163528418980.3925689.5841907054957931211.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/idxd/device.c

@@ -411,12 +411,20 @@ int idxd_wq_init_percpu_ref(struct idxd_wq *wq)
 	return 0;
 }
 
-void idxd_wq_quiesce(struct idxd_wq *wq)
+void __idxd_wq_quiesce(struct idxd_wq *wq)
 {
+	lockdep_assert_held(&wq->wq_lock);
 	percpu_ref_kill(&wq->wq_active);
 	wait_for_completion(&wq->wq_dead);
 }
 
+void idxd_wq_quiesce(struct idxd_wq *wq)
+{
+	mutex_lock(&wq->wq_lock);
+	__idxd_wq_quiesce(wq);
+	mutex_unlock(&wq->wq_lock);
+}
+
 /* Device control bits */
 static inline bool idxd_is_enabled(struct idxd_device *idxd)
 {

drivers/dma/idxd/dma.c

@@ -316,7 +316,7 @@ static int idxd_dmaengine_drv_probe(struct idxd_dev *idxd_dev)
 	return 0;
 
 err_dma:
-	idxd_wq_quiesce(wq);
+	__idxd_wq_quiesce(wq);
 	percpu_ref_exit(&wq->wq_active);
 err_ref:
 	idxd_wq_free_resources(wq);
@@ -333,7 +333,7 @@ static void idxd_dmaengine_drv_remove(struct idxd_dev *idxd_dev)
 	struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev);
 
 	mutex_lock(&wq->wq_lock);
-	idxd_wq_quiesce(wq);
+	__idxd_wq_quiesce(wq);
 	idxd_unregister_dma_channel(wq);
 	idxd_wq_free_resources(wq);
 	__drv_disable_wq(wq);

drivers/dma/idxd/idxd.h

@@ -570,6 +570,7 @@ int idxd_wq_map_portal(struct idxd_wq *wq);
 void idxd_wq_unmap_portal(struct idxd_wq *wq);
 int idxd_wq_set_pasid(struct idxd_wq *wq, int pasid);
 int idxd_wq_disable_pasid(struct idxd_wq *wq);
+void __idxd_wq_quiesce(struct idxd_wq *wq);
 void idxd_wq_quiesce(struct idxd_wq *wq);
 int idxd_wq_init_percpu_ref(struct idxd_wq *wq);