[PATCH AUTOSEL 4.19 17/18] net: ethernet: mtk_eth_soc: fix misuse of mem alloc interface netdev[napi]_alloc_frag

Sasha Levin
2022-06-14T02:25:31Z

From: Chen Lin <chen45464546@163.com>

[ Upstream commit 2f2c0d2919a14002760f89f4e02960c735a316d2 ]

When rx_flag == MTK_RX_FLAGS_HWLRO,
rx_data_len = MTK_MAX_LRO_RX_LENGTH(4096 * 3) > PAGE_SIZE.
netdev_alloc_frag is for alloction of page fragment only.
Reference to other drivers and Documentation/vm/page_frags.rst

Branch to use __get_free_pages when ring->frag_size > PAGE_SIZE.

Signed-off-by: Chen Lin <chen45464546@163.com>
Link: https://lore.kernel.org/r/1654692413-2598-1-git-send-email-chen45464546@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 59f3dce3ab1d..d0f2488003eb 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -597,6 +597,17 @@ static inline void mtk_rx_get_desc(struct mtk_rx_dma *rxd,
rxd->rxd4 = READ_ONCE(dma_rxd->rxd4);
}

+static void *mtk_max_lro_buf_alloc(gfp_t gfp_mask)
+{
+ unsigned int size = mtk_max_frag_size(MTK_MAX_LRO_RX_LENGTH);
+ unsigned long data;
+
+ data = __get_free_pages(gfp_mask | __GFP_COMP | __GFP_NOWARN,
+ get_order(size));
+
+ return (void *)data;
+}
+
/* the qdma core needs scratch memory to be setup */
static int mtk_init_fq_dma(struct mtk_eth *eth)
{
@@ -1005,7 +1016,10 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
goto release_desc;

/* alloc new buffer */
- new_data = napi_alloc_frag(ring->frag_size);
+ if (ring->frag_size <= PAGE_SIZE)
+ new_data = napi_alloc_frag(ring->frag_size);
+ else
+ new_data = mtk_max_lro_buf_alloc(GFP_ATOMIC);
if (unlikely(!new_data)) {
netdev->stats.rx_dropped++;
goto release_desc;
@@ -1312,7 +1326,10 @@ static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)
return -ENOMEM;

for (i = 0; i < rx_dma_size; i++) {
- ring->data[i] = netdev_alloc_frag(ring->frag_size);
+ if (ring->frag_size <= PAGE_SIZE)
+ ring->data[i] = netdev_alloc_frag(ring->frag_size);
+ else
+ ring->data[i] = mtk_max_lro_buf_alloc(GFP_KERNEL);
if (!ring->data[i])
return -ENOMEM;
}
--
2.35.1