RE: [EXT] [PATCH net] net: mvneta: fix the Rx desc buffer DMA unmapping

[Yelena Krivosheev]

Hi Antoine.

Good point.
Please, check and fix all cases of dma_unmap_single() usage.
See mvneta_rxq_drop_pkts()
...
		if (!data || !(rx_desc->buf_phys_addr))
			continue;
		dma_unmap_single(pp->dev->dev.parent, rx_desc->buf_phys_addr,
				 MVNETA_RX_BUF_SIZE(pp->pkt_size), DMA_FROM_DEVICE);
		__free_page(data);
...

Thanks.
Yelena


-----Original Message-----
From: Antoine Tenart [mailto:antoine.tenart@xxxxxxxxxxx] 
Sent: Wednesday, September 19, 2018 4:29 PM
To: davem@xxxxxxxxxxxxx; Yelena Krivosheev <yelena@xxxxxxxxxxx>
Cc: Antoine Tenart <antoine.tenart@xxxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; thomas.petazzoni@xxxxxxxxxxx; maxime.chevallier@xxxxxxxxxxx; gregory.clement@xxxxxxxxxxx; miquel.raynal@xxxxxxxxxxx; Nadav Haklai <nadavh@xxxxxxxxxxx>; Stefan Chulski <stefanc@xxxxxxxxxxx>; Yan Markman <ymarkman@xxxxxxxxxxx>; mw@xxxxxxxxxxxx
Subject: [EXT] [PATCH net] net: mvneta: fix the Rx desc buffer DMA unmapping

External Email

----------------------------------------------------------------------
With CONFIG_DMA_API_DEBUG enabled we now get a warning when using the mvneta driver:

  mvneta d0030000.ethernet: DMA-API: device driver frees DMA memory with
  wrong function [device address=0x000000001165b000] [size=4096 bytes]
  [mapped as page] [unmapped as single]

This is because when using the s/w buffer management, the Rx descriptor buffer is mapped with dma_map_page but unmapped with dma_unmap_single.
This patch fixes this by using the right unmapping function.

Fixes: 562e2f467e71 ("net: mvneta: Improve the buffer allocation method for SWBM")
Signed-off-by: Antoine Tenart <antoine.tenart@xxxxxxxxxxx>
---
 drivers/net/ethernet/marvell/mvneta.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index bc80a678abc3..2db9708f2e24 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2008,8 +2008,8 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 				skb_add_rx_frag(rxq->skb, frag_num, page,
 						frag_offset, frag_size,
 						PAGE_SIZE);
-				dma_unmap_single(dev->dev.parent, phys_addr,
-						 PAGE_SIZE, DMA_FROM_DEVICE);
+				dma_unmap_page(dev->dev.parent, phys_addr,
+					       PAGE_SIZE, DMA_FROM_DEVICE);
 				rxq->left_size -= frag_size;
 			}
 		} else {
--
2.17.1