[PATCH 2/3] tun: fix tun_chr_aio_read so that aio works
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2009-04-20 11:27:08
Subsystem:
networking drivers, the rest, tun/tap driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn, Jason Wang
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: Michael S. Tsirkin <mst@redhat.com> --- drivers/net/tun.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 16716ae..24c19c2 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c@@ -679,7 +679,7 @@ 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;
@@ -693,7 +693,7 @@ 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); }
@@ -726,14 +726,15 @@ 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++;
@@ -788,7 +789,7 @@ 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; }
--
1.6.0.6