[PATCH net-next v4 12/15] net: stmmac: add helper to get size of a transmit descriptor

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

Add and use a helper to get the size of the hardware transmit
descriptor.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 40 +++++++------------
 1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 76e4dcf8f697..da1726b887f3 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -362,6 +362,17 @@ static inline u32 stmmac_tx_avail(struct stmmac_priv *priv, u32 queue)
 			  priv->dma_conf.dma_tx_size);
 }
 
+static size_t stmmac_get_tx_desc_size(struct stmmac_priv *priv,
+				      struct stmmac_tx_queue *tx_q)
+{
+	if (priv->extend_desc)
+		return sizeof(struct dma_extended_desc);
+	else if (tx_q->tbs & STMMAC_TBS_AVAIL)
+		return sizeof(struct dma_edesc);
+	else
+		return sizeof(struct dma_desc);
+}
+
 static struct dma_desc *stmmac_get_tx_desc(struct stmmac_priv *priv,
 					   struct stmmac_tx_queue *tx_q,
 					   unsigned int index)
@@ -1501,14 +1512,8 @@ static void stmmac_display_tx_rings(struct stmmac_priv *priv,
 
 		pr_info("\tTX Queue %d rings\n", queue);
 
-		if (priv->extend_desc)
-			desc_size = sizeof(struct dma_extended_desc);
-		else if (tx_q->tbs & STMMAC_TBS_AVAIL)
-			desc_size = sizeof(struct dma_edesc);
-		else
-			desc_size = sizeof(struct dma_desc);
-
 		head_tx = stmmac_get_tx_desc(priv, tx_q, 0);
+		desc_size = stmmac_get_tx_desc_size(priv, tx_q);
 
 		stmmac_display_ring(priv, head_tx, dma_conf->dma_tx_size, false,
 				    tx_q->dma_tx_phy, desc_size);
@@ -2186,17 +2191,14 @@ static void __free_dma_tx_desc_resources(struct stmmac_priv *priv,
 	dma_free_tx_skbufs(priv, dma_conf, queue);
 
 	if (priv->extend_desc) {
-		size = sizeof(struct dma_extended_desc);
 		addr = tx_q->dma_etx;
 	} else if (tx_q->tbs & STMMAC_TBS_AVAIL) {
-		size = sizeof(struct dma_edesc);
 		addr = tx_q->dma_entx;
 	} else {
-		size = sizeof(struct dma_desc);
 		addr = tx_q->dma_tx;
 	}
 
-	size *= dma_conf->dma_tx_size;
+	size = stmmac_get_tx_desc_size(priv, tx_q) * dma_conf->dma_tx_size;
 
 	dma_free_coherent(priv->device, size, addr, tx_q->dma_tx_phy);
 
@@ -2358,14 +2360,7 @@ static int __alloc_dma_tx_desc_resources(struct stmmac_priv *priv,
 	if (!tx_q->tx_skbuff)
 		return -ENOMEM;
 
-	if (priv->extend_desc)
-		size = sizeof(struct dma_extended_desc);
-	else if (tx_q->tbs & STMMAC_TBS_AVAIL)
-		size = sizeof(struct dma_edesc);
-	else
-		size = sizeof(struct dma_desc);
-
-	size *= dma_conf->dma_tx_size;
+	size = stmmac_get_tx_desc_size(priv, tx_q) * dma_conf->dma_tx_size;
 
 	addr = dma_alloc_coherent(priv->device, size,
 				  &tx_q->dma_tx_phy, GFP_KERNEL);
@@ -4333,12 +4328,7 @@ static void stmmac_flush_tx_descriptors(struct stmmac_priv *priv, int queue)
 	struct stmmac_tx_queue *tx_q = &priv->dma_conf.tx_queue[queue];
 	int desc_size;
 
-	if (likely(priv->extend_desc))
-		desc_size = sizeof(struct dma_extended_desc);
-	else if (tx_q->tbs & STMMAC_TBS_AVAIL)
-		desc_size = sizeof(struct dma_edesc);
-	else
-		desc_size = sizeof(struct dma_desc);
+	desc_size = stmmac_get_tx_desc_size(priv, tx_q);
 
 	/* The own bit must be the latest setting done when prepare the
 	 * descriptor and then barrier is needed to make sure that
-- 
2.47.3