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net: tun: rebuild error handling in tun_get_user

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[ 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>
This commit is contained in:
Chuang Wang 2022-11-10 15:31:25 +08:00 committed by Greg Kroah-Hartman
parent ae42c6f79c
commit e2d59768f8
1 changed files with 29 additions and 36 deletions
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65
drivers/net/tun.c
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@ -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)