From: Chuang Wang <nashuiliang@xxxxxxxxx>
[ 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@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 82b2bc279467 ("tun: Fix memory leak for detached NAPI queue.")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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)
--
2.39.2
