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Commit 0bbd7dad authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tun: make tun_build_skb() thread safe 



tun_build_skb() is not thread safe since it uses per queue page frag,
this will break things when multiple threads are sending through same
queue. Switch to use per-thread generator (no lock involved).

Fixes: 66ccbc9c ("tap: use build_skb() for small packet")
Tested-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ba5c4dac

drivers/net/tun.c

+1 −6
Original line number Diff line number Diff line
@@ -175,7 +175,6 @@ struct tun_file { 
	struct list_head next;

	struct tun_struct *detached;

	struct skb_array tx_array;

	struct page_frag alloc_frag;

};



struct tun_flow_entry {
@@ -578,8 +577,6 @@ static void __tun_detach(struct tun_file *tfile, bool clean) 
		}

		if (tun)

			skb_array_cleanup(&tfile->tx_array);

		if (tfile->alloc_frag.page)

			put_page(tfile->alloc_frag.page);

		sock_put(&tfile->sk);

	}

}
@@ -1272,7 +1269,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, 
				     struct virtio_net_hdr *hdr,

				     int len, int *generic_xdp)

{

	struct page_frag *alloc_frag = &tfile->alloc_frag;

	struct page_frag *alloc_frag = &current->task_frag;

	struct sk_buff *skb;

	struct bpf_prog *xdp_prog;

	int buflen = SKB_DATA_ALIGN(len + TUN_RX_PAD) +
@@ -2580,8 +2577,6 @@ static int tun_chr_open(struct inode *inode, struct file * file) 
	tfile->sk.sk_write_space = tun_sock_write_space;

	tfile->sk.sk_sndbuf = INT_MAX;



	tfile->alloc_frag.page = NULL;



	file->private_data = tfile;

	INIT_LIST_HEAD(&tfile->next);