| Message ID | 1502879084.4936.95.camel@edumazet-glaptop3.roam.corp.google.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On 2017年08月16日 18:24, Eric Dumazet wrote: > On Wed, 2017-08-16 at 11:55 +0800, Jason Wang wrote: >> On 2017年08月16日 11:45, Eric Dumazet wrote: >>> You do realize that tun_build_skb() is not thread safe ? >> Ok, I think the issue if skb_page_frag_refill(), need a spinlock >> probably. Will prepare a patch. > But since tun is used from process context, why don't you use the > per-thread generator (no lock involved) Haven't noticed this before. > > tcp_sendmsg() uses this for GFP_KERNEL allocations. > > Untested patch : > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 5892284eb8d05b0678d820bad3d0d2c61a879aeb..c38cd840cc0b7fecf182b23976e36f709cacca1f 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); > > > > > Tested-by: Jason Wang <jasowang@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 5892284eb8d05b0678d820bad3d0d2c61a879aeb..c38cd840cc0b7fecf182b23976e36f709cacca1f 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);