Subject: [PATCH AUTOSEL 5.3 61/71] net: stmmac: Fix page pool size

From: Sasha Levin <[email-masked]>
Date: Tue, 1 Oct 2019 12:39:11 -0400

From: Thierry Reding <[email-masked]>

[ 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 <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b19ab09cb18f7..5c4408bdc843a 100644
--- 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(struct stmmac_priv *priv)
 	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;
-- 
2.20.1