Re: [PATCH net-next v4 08/15] net: macb: avoid macb_init_rx_buffer_size() modifying state

macb_init_rx_buffer_size() takes the macb private data struct and
overrides its bp->ctx->rx_buffer_size. To make it usable with multiple
contexts, make it return its value.

Also, move the `bufsz` computation into it. The value is only used if
GEM, and for historical reason it currently lives in macb_open().

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 26 
+++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c 

b/drivers/net/ethernet/cadence/macb_main.c
index d50d8520231c..29bf3c497f2a 100644

--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c

@@ -2615,25 +2615,26 @@ static netdev_tx_t macb_start_xmit(struct 

sk_buff *skb,
 	return ret;
 }

-static void macb_init_rx_buffer_size(struct macb *bp, size_t size)
+static unsigned int macb_rx_buffer_size(struct macb *bp, unsigned int 
mtu)
 {
-	if (!macb_is_gem(bp)) {
-		bp->ctx->rx_buffer_size = MACB_RX_BUFFER_SIZE;
-	} else {
-		bp->ctx->rx_buffer_size = MIN(size, RX_BUFFER_MAX);
+	unsigned int size;

-		if (bp->ctx->rx_buffer_size % RX_BUFFER_MULTIPLE) {
+	if (!macb_is_gem(bp)) {
+		size = MACB_RX_BUFFER_SIZE;
+	} else {
+		size = mtu + ETH_HLEN + ETH_FCS_LEN + NET_IP_ALIGN;
+		size = MIN(size, RX_BUFFER_MAX);
+
+		if (size % RX_BUFFER_MULTIPLE) {
 			netdev_dbg(bp->netdev,
 				   "RX buffer must be multiple of %d bytes, expanding\n",
 				   RX_BUFFER_MULTIPLE);
-			bp->ctx->rx_buffer_size =
-				roundup(bp->ctx->rx_buffer_size,
-					RX_BUFFER_MULTIPLE);
+			size = roundup(size, RX_BUFFER_MULTIPLE);
 		}
 	}

-	netdev_dbg(bp->netdev, "mtu [%u] rx_buffer_size [%u]\n",
-		   bp->netdev->mtu, bp->ctx->rx_buffer_size);
+	netdev_dbg(bp->netdev, "mtu [%u] rx_buffer_size [%u]\n", mtu, size);
+	return size;
 }

 static void gem_free_rx_buffers(struct macb *bp)

@@ -3193,7 +3194,6 @@ static void macb_set_rx_mode(struct net_device 

*netdev)

 static int macb_open(struct net_device *netdev)
 {
-	size_t bufsz = netdev->mtu + ETH_HLEN + ETH_FCS_LEN + NET_IP_ALIGN;
 	struct macb *bp = netdev_priv(netdev);
 	struct macb_queue *queue;
 	unsigned int q;

@@ -3212,7 +3212,7 @@ static int macb_open(struct net_device *netdev)
 	}

 	/* RX buffers initialization */
-	macb_init_rx_buffer_size(bp, bufsz);
+	bp->ctx->rx_buffer_size = macb_rx_buffer_size(bp, netdev->mtu);
 	bp->ctx->rx_ring_size = bp->configured_rx_ring_size;
 	bp->ctx->tx_ring_size = bp->configured_tx_ring_size;