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Commit 69712e5d authored by Alexander Kochetkov's avatar Alexander Kochetkov Committed by Greg Kroah-Hartman
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net: arc_emac: fix arc_emac_rx() error paths 




[ Upstream commit e688822d035b494071ecbadcccbd6f3325fb0f59 ]

arc_emac_rx() has some issues found by code review.

In case netdev_alloc_skb_ip_align() or dma_map_single() failure
rx fifo entry will not be returned to EMAC.

In case dma_map_single() failure previously allocated skb became
lost to driver. At the same time address of newly allocated skb
will not be provided to EMAC.

Signed-off-by: default avatarAlexander Kochetkov <al.kochet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bfde9f19

drivers/net/ethernet/arc/emac_main.c

+31 −22
Original line number Diff line number Diff line
@@ -250,39 +250,48 @@ static int arc_emac_rx(struct net_device *ndev, int budget) 
			continue;

		}



		pktlen = info & LEN_MASK;

		stats->rx_packets++;

		stats->rx_bytes += pktlen;

		skb = rx_buff->skb;

		skb_put(skb, pktlen);

		skb->dev = ndev;

		skb->protocol = eth_type_trans(skb, ndev);



		dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),

				 dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);



		/* Prepare the BD for next cycle */

		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,

							 EMAC_BUFFER_SIZE);

		if (unlikely(!rx_buff->skb)) {

		/* Prepare the BD for next cycle. netif_receive_skb()

		 * only if new skb was allocated and mapped to avoid holes

		 * in the RX fifo.

		 */

		skb = netdev_alloc_skb_ip_align(ndev, EMAC_BUFFER_SIZE);

		if (unlikely(!skb)) {

			if (net_ratelimit())

				netdev_err(ndev, "cannot allocate skb\n");

			/* Return ownership to EMAC */

			rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);

			stats->rx_errors++;

			/* Because receive_skb is below, increment rx_dropped */

			stats->rx_dropped++;

			continue;

		}



		/* receive_skb only if new skb was allocated to avoid holes */

		netif_receive_skb(skb);



		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,

		addr = dma_map_single(&ndev->dev, (void *)skb->data,

				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);

		if (dma_mapping_error(&ndev->dev, addr)) {

			if (net_ratelimit())

				netdev_err(ndev, "cannot dma map\n");

			dev_kfree_skb(rx_buff->skb);

				netdev_err(ndev, "cannot map dma buffer\n");

			dev_kfree_skb(skb);

			/* Return ownership to EMAC */

			rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);

			stats->rx_errors++;

			stats->rx_dropped++;

			continue;

		}



		/* unmap previosly mapped skb */

		dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),

				 dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);



		pktlen = info & LEN_MASK;

		stats->rx_packets++;

		stats->rx_bytes += pktlen;

		skb_put(rx_buff->skb, pktlen);

		rx_buff->skb->dev = ndev;

		rx_buff->skb->protocol = eth_type_trans(rx_buff->skb, ndev);



		netif_receive_skb(rx_buff->skb);



		rx_buff->skb = skb;

		dma_unmap_addr_set(rx_buff, addr, addr);

		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);