From foo@baz Tue 01 Oct 2019 03:27:55 PM CEST
From: Thierry Reding <treding@nvidia.com>
Date: Mon, 23 Sep 2019 11:59:15 +0200
Subject: net: stmmac: Fix page pool size

From: Thierry Reding <treding@nvidia.com>

[ Upstream commit 4f28bd956e081fc018fe9b41ffa31573f17bfb61 ]

The size of individual pages in the page pool in given by an order. The
order is the binary logarithm of the number of pages that make up one of
the pages in the pool. However, the driver currently passes the number
of pages rather than the order, so it ends up wasting quite a bit of
memory.

Fix this by taking the binary logarithm and passing that in the order
field.

Fixes: 2af6106ae949 ("net: stmmac: Introducing support for Page Pool")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1532,13 +1532,15 @@ static int alloc_dma_rx_desc_resources(s
 	for (queue = 0; queue < rx_count; queue++) {
 		struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
 		struct page_pool_params pp_params = { 0 };
+		unsigned int num_pages;
 
 		rx_q->queue_index = queue;
 		rx_q->priv_data = priv;
 
 		pp_params.flags = PP_FLAG_DMA_MAP;
 		pp_params.pool_size = DMA_RX_SIZE;
-		pp_params.order = DIV_ROUND_UP(priv->dma_buf_sz, PAGE_SIZE);
+		num_pages = DIV_ROUND_UP(priv->dma_buf_sz, PAGE_SIZE);
+		pp_params.order = ilog2(num_pages);
 		pp_params.nid = dev_to_node(priv->device);
 		pp_params.dev = priv->device;
 		pp_params.dma_dir = DMA_FROM_DEVICE;