Messages in this thread | | | Date | Wed, 16 Aug 2017 19:55:09 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH] tun: make tun_build_skb() thread safe |
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On Wed, Aug 16, 2017 at 10:14:33PM +0800, Jason Wang wrote: > From: Eric Dumazet <eric.dumazet@gmail.com> > > 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 <jasowang@redhat.com> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Jason, given the switch to task_frag, would it be worth it to look at using higher order allocs along the lines of 5640f7685831e088fe6c2e1f863a6805962f8e81 as well?
> --- > drivers/net/tun.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 5892284..c38cd84 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); > > -- > 2.7.4
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