dmaengine: cleanup with list_first_entry_or_null()

The combo of list_empty() check and return list_first_entry()
can be replaced with list_first_entry_or_null().
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/coh901318.c

@@ -1553,15 +1553,8 @@ coh901318_desc_submit(struct coh901318_chan *cohc, struct coh901318_desc *desc)
 static struct coh901318_desc *
 coh901318_first_active_get(struct coh901318_chan *cohc)
 {
-	struct coh901318_desc *d;
-
-	if (list_empty(&cohc->active))
-		return NULL;
-
-	d = list_first_entry(&cohc->active,
-			     struct coh901318_desc,
+	return list_first_entry_or_null(&cohc->active, struct coh901318_desc,
 					node);
-	return d;
 }
 
 static void
@@ -1579,15 +1572,8 @@ coh901318_desc_queue(struct coh901318_chan *cohc, struct coh901318_desc *desc)
 static struct coh901318_desc *
 coh901318_first_queued(struct coh901318_chan *cohc)
 {
-	struct coh901318_desc *d;
-
-	if (list_empty(&cohc->queue))
-		return NULL;
-
-	d = list_first_entry(&cohc->queue,
-			     struct coh901318_desc,
+	return list_first_entry_or_null(&cohc->queue, struct coh901318_desc,
 					node);
-	return d;
 }
 
 static inline u32 coh901318_get_bytes_in_lli(struct coh901318_lli *in_lli)

drivers/dma/ep93xx_dma.c

@@ -262,10 +262,8 @@ static void ep93xx_dma_set_active(struct ep93xx_dma_chan *edmac,
 static struct ep93xx_dma_desc *
 ep93xx_dma_get_active(struct ep93xx_dma_chan *edmac)
 {
-	if (list_empty(&edmac->active))
-		return NULL;
-
-	return list_first_entry(&edmac->active, struct ep93xx_dma_desc, node);
+	return list_first_entry_or_null(&edmac->active,
+					struct ep93xx_dma_desc, node);
 }
 
 /**

drivers/dma/ste_dma40.c

@@ -941,15 +941,7 @@ static void d40_desc_load(struct d40_chan *d40c, struct d40_desc *d40d)
 
 static struct d40_desc *d40_first_active_get(struct d40_chan *d40c)
 {
-	struct d40_desc *d;
-
-	if (list_empty(&d40c->active))
-		return NULL;
-
-	d = list_first_entry(&d40c->active,
-			     struct d40_desc,
-			     node);
-	return d;
+	return list_first_entry_or_null(&d40c->active, struct d40_desc, node);
 }
 
 /* remove desc from current queue and add it to the pending_queue */
@@ -962,36 +954,18 @@ static void d40_desc_queue(struct d40_chan *d40c, struct d40_desc *desc)
 
 static struct d40_desc *d40_first_pending(struct d40_chan *d40c)
 {
-	struct d40_desc *d;
-
-	if (list_empty(&d40c->pending_queue))
-		return NULL;
-
-	d = list_first_entry(&d40c->pending_queue,
-			     struct d40_desc,
+	return list_first_entry_or_null(&d40c->pending_queue, struct d40_desc,
 					node);
-	return d;
 }
 
 static struct d40_desc *d40_first_queued(struct d40_chan *d40c)
 {
-	struct d40_desc *d;
-
-	if (list_empty(&d40c->queue))
-		return NULL;
-
-	d = list_first_entry(&d40c->queue,
-			     struct d40_desc,
-			     node);
-	return d;
+	return list_first_entry_or_null(&d40c->queue, struct d40_desc, node);
 }
 
 static struct d40_desc *d40_first_done(struct d40_chan *d40c)
 {
-	if (list_empty(&d40c->done))
-		return NULL;
-
-	return list_first_entry(&d40c->done, struct d40_desc, node);
+	return list_first_entry_or_null(&d40c->done, struct d40_desc, node);
 }
 
 static int d40_psize_2_burst_size(bool is_log, int psize)

drivers/dma/virt-dma.h

@@ -123,10 +123,8 @@ static inline void vchan_cyclic_callback(struct virt_dma_desc *vd)
  */
 static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
 {
-	if (list_empty(&vc->desc_issued))
-		return NULL;
-
-	return list_first_entry(&vc->desc_issued, struct virt_dma_desc, node);
+	return list_first_entry_or_null(&vc->desc_issued,
+					struct virt_dma_desc, node);
 }
 
 /**