dmaengine: virt-dma: Do not call desc_free() under a spin_lock

vchan_vdesc_fini() shouldn't be called under a spin_lock. This is done
in two places, once in vchan_terminate_vdesc() and once in
vchan_synchronize(). Instead of freeing the vdesc right away, collect
the aborted vdescs on a separate list and free them along with the other
vdescs. The terminated descs are also freed in vchan_synchronize as done
before this patch.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20191216105328.15198-5-s.hauer@pengutronix.deSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/virt-dma.c

@@ -138,6 +138,7 @@ void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev)
 	INIT_LIST_HEAD(&vc->desc_submitted);
 	INIT_LIST_HEAD(&vc->desc_issued);
 	INIT_LIST_HEAD(&vc->desc_completed);
+	INIT_LIST_HEAD(&vc->desc_terminated);
 
 	tasklet_init(&vc->task, vchan_complete, (unsigned long)vc);
 

drivers/dma/virt-dma.h

@@ -31,9 +31,9 @@ struct virt_dma_chan {
 	struct list_head desc_submitted;
 	struct list_head desc_issued;
 	struct list_head desc_completed;
+	struct list_head desc_terminated;
 
 	struct virt_dma_desc *cyclic;
-	struct virt_dma_desc *vd_terminated;
 };
 
 static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan)
@@ -141,11 +141,8 @@ static inline void vchan_terminate_vdesc(struct virt_dma_desc *vd)
 {
 	struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
 
-	/* free up stuck descriptor */
-	if (vc->vd_terminated)
-		vchan_vdesc_fini(vc->vd_terminated);
+	list_add_tail(&vd->node, &vc->desc_terminated);
 
-	vc->vd_terminated = vd;
 	if (vc->cyclic == vd)
 		vc->cyclic = NULL;
 }
@@ -179,6 +176,7 @@ static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc,
 	list_splice_tail_init(&vc->desc_submitted, head);
 	list_splice_tail_init(&vc->desc_issued, head);
 	list_splice_tail_init(&vc->desc_completed, head);
+	list_splice_tail_init(&vc->desc_terminated, head);
 }
 
 static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
@@ -207,16 +205,18 @@ static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
  */
 static inline void vchan_synchronize(struct virt_dma_chan *vc)
 {
+	LIST_HEAD(head);
 	unsigned long flags;
 
 	tasklet_kill(&vc->task);
 
 	spin_lock_irqsave(&vc->lock, flags);
-	if (vc->vd_terminated) {
-		vchan_vdesc_fini(vc->vd_terminated);
-		vc->vd_terminated = NULL;
-	}
+
+	list_splice_tail_init(&vc->desc_terminated, &head);
+
 	spin_unlock_irqrestore(&vc->lock, flags);
+
+	vchan_dma_desc_free_list(vc, &head);
 }
 
 #endif