From: Chuang Wang nashuiliang@gmail.com
[ Upstream commit ab00af85d2f886a8e4ace1342d9cc2b232eab6a8 ]
The error handling in tun_get_user is very scattered. This patch unifies error handling, reduces duplication of code, and makes the logic clearer.
Signed-off-by: Chuang Wang nashuiliang@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: 82b2bc279467 ("tun: Fix memory leak for detached NAPI queue.") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/tun.c | 65 +++++++++++++++++++++-------------------------- 1 file changed, 29 insertions(+), 36 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 91d198aff2f9a..65706824eb828 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1748,7 +1748,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash = 0; int skb_xdp = 1; bool frags = tun_napi_frags_enabled(tfile); - enum skb_drop_reason drop_reason; + enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) @@ -1809,10 +1809,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, * skb was created with generic XDP routine. */ skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp); - if (IS_ERR(skb)) { - dev_core_stats_rx_dropped_inc(tun->dev); - return PTR_ERR(skb); - } + err = PTR_ERR_OR_ZERO(skb); + if (err) + goto drop; if (!skb) return total_len; } else { @@ -1837,13 +1836,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, noblock); }
- if (IS_ERR(skb)) { - if (PTR_ERR(skb) != -EAGAIN) - dev_core_stats_rx_dropped_inc(tun->dev); - if (frags) - mutex_unlock(&tfile->napi_mutex); - return PTR_ERR(skb); - } + err = PTR_ERR_OR_ZERO(skb); + if (err) + goto drop;
if (zerocopy) err = zerocopy_sg_from_iter(skb, from); @@ -1853,27 +1848,14 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (err) { err = -EFAULT; drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT; -drop: - dev_core_stats_rx_dropped_inc(tun->dev); - kfree_skb_reason(skb, drop_reason); - if (frags) { - tfile->napi.skb = NULL; - mutex_unlock(&tfile->napi_mutex); - } - - return err; + goto drop; } }
if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) { atomic_long_inc(&tun->rx_frame_errors); - kfree_skb(skb); - if (frags) { - tfile->napi.skb = NULL; - mutex_unlock(&tfile->napi_mutex); - } - - return -EINVAL; + err = -EINVAL; + goto free_skb; }
switch (tun->flags & TUN_TYPE_MASK) { @@ -1889,9 +1871,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, pi.proto = htons(ETH_P_IPV6); break; default: - dev_core_stats_rx_dropped_inc(tun->dev); - kfree_skb(skb); - return -EINVAL; + err = -EINVAL; + goto drop; } }
@@ -1933,11 +1914,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (ret != XDP_PASS) { rcu_read_unlock(); local_bh_enable(); - if (frags) { - tfile->napi.skb = NULL; - mutex_unlock(&tfile->napi_mutex); - } - return total_len; + goto unlock_frags; } } rcu_read_unlock(); @@ -2017,6 +1994,22 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, tun_flow_update(tun, rxhash, tfile);
return total_len; + +drop: + if (err != -EAGAIN) + dev_core_stats_rx_dropped_inc(tun->dev); + +free_skb: + if (!IS_ERR_OR_NULL(skb)) + kfree_skb_reason(skb, drop_reason); + +unlock_frags: + if (frags) { + tfile->napi.skb = NULL; + mutex_unlock(&tfile->napi_mutex); + } + + return err ?: total_len; }
static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)