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Commit cd1973a9 authored by Ilias Apalodimas's avatar Ilias Apalodimas Committed by David S. Miller
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net: netsec: Sync dma for device on buffer allocation 



Quoting Arnd,

We have to do a sync_single_for_device /somewhere/ before the
buffer is given to the device. On a non-cache-coherent machine with
a write-back cache, there may be dirty cache lines that get written back
after the device DMA's data into it (e.g. from a previous memset
from before the buffer got freed), so you absolutely need to flush any
dirty cache lines on it first.

Since the coherency is configurable in this device make sure we cover
all configurations by explicitly syncing the allocated buffer for the
device before refilling it's descriptors

Signed-off-by: default avatarIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2bf8001e

drivers/net/ethernet/socionext/netsec.c

+5 −0
Original line number Diff line number Diff line
@@ -726,6 +726,7 @@ static void *netsec_alloc_rx_data(struct netsec_priv *priv, 
{



	struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];

	enum dma_data_direction dma_dir;

	struct page *page;



	page = page_pool_dev_alloc_pages(dring->page_pool);
@@ -741,6 +742,10 @@ static void *netsec_alloc_rx_data(struct netsec_priv *priv, 
	 * cases and reserve enough space for headroom + skb_shared_info

	 */

	*desc_len = PAGE_SIZE - NETSEC_RX_BUF_NON_DATA;

	dma_dir = page_pool_get_dma_dir(dring->page_pool);

	dma_sync_single_for_device(priv->dev,

				   *dma_handle - NETSEC_RXBUF_HEADROOM,

				   PAGE_SIZE, dma_dir);



	return page_address(page);

}