Commit ab00af85 authored by Chuang Wang's avatar Chuang Wang Committed by David S. Miller
Browse files

net: tun: rebuild error handling in tun_get_user 



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: default avatarChuang Wang <nashuiliang@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b548b17a

drivers/net/tun.c

+29 −36
Original line number Diff line number Diff line
@@ -1746,7 +1746,7 @@ 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))
@@ -1807,10 +1807,9 @@ 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 {
@@ -1835,13 +1834,9 @@ 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);
@@ -1851,27 +1846,14 @@ 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) {
@@ -1887,9 +1869,8 @@ 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;

			}

		}
@@ -1931,11 +1912,7 @@ 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();
@@ -2015,6 +1992,22 @@ 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)