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Commit 43b39dcd authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by David S. Miller
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tun: fix tun_chr_aio_read so that aio works 



aio_read gets const struct iovec * but tun_chr_aio_read casts this to struct
iovec * and modifies the iovec. As a result, attempts to use io_submit
to get packets from a tun device fail with weird errors such as EINVAL.

Fix by using the new skb_copy_datagram_const_iovec.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0a1ec07a

drivers/net/tun.c

+6 −5
Original line number Diff line number Diff line
@@ -683,7 +683,7 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, 
/* Put packet to the user space buffer */

static __inline__ ssize_t tun_put_user(struct tun_struct *tun,

				       struct sk_buff *skb,

				       struct iovec *iv, int len)

				       const struct iovec *iv, int len)

{

	struct tun_pi pi = { 0, skb->protocol };

	ssize_t total = 0;
@@ -697,7 +697,7 @@ static __inline__ ssize_t tun_put_user(struct tun_struct *tun, 
			pi.flags |= TUN_PKT_STRIP;

		}



		if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))

		if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))

			return -EFAULT;

		total += sizeof(pi);

	}
@@ -730,14 +730,15 @@ static __inline__ ssize_t tun_put_user(struct tun_struct *tun, 
			gso.csum_offset = skb->csum_offset;

		} /* else everything is zero */



		if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))

		if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,

					       sizeof(gso))))

			return -EFAULT;

		total += sizeof(gso);

	}



	len = min_t(int, skb->len, len);



	skb_copy_datagram_iovec(skb, 0, iv, len);

	skb_copy_datagram_const_iovec(skb, 0, iv, total, len);

	total += len;



	tun->dev->stats.tx_packets++;
@@ -792,7 +793,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, 
		}

		netif_wake_queue(tun->dev);



		ret = tun_put_user(tun, skb, (struct iovec *) iv, len);

		ret = tun_put_user(tun, skb, iv, len);

		kfree_skb(skb);

		break;

	}