From: Eric Dumazet Date: Wed, 16 Aug 2017 14:14:33 +0000 (+0800) Subject: tun: make tun_build_skb() thread safe X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=0bbd7dad34f81e5e724cb08252160a1796c388b2;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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: 66ccbc9c87c2 ("tap: use build_skb() for small packet") Tested-by: Jason Wang Signed-off-by: Eric Dumazet Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- diff --git a/drivers/net/tun.c b/drivers/net/tun.c index f5017121cd57..19cbbbb1b63b 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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 = ¤t->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);