Juntong Deng wrote:
> Currently getsockopt does not support PACKET_COPY_THRESH,
> and we are unable to get the value of PACKET_COPY_THRESH
> socket option through getsockopt.
>
> This patch adds getsockopt support for PACKET_COPY_THRESH.
>
> Signed-off-by: Juntong Deng <[email protected]>
> ---
> net/packet/af_packet.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 0db31ca4982d..65042edd1a97 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -4090,6 +4090,9 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
> case PACKET_VNET_HDR_SZ:
> val = READ_ONCE(po->vnet_hdr_sz);
> break;
> + case PACKET_COPY_THRESH:
> + val = pkt_sk(sk)->copy_thresh;
> + break;
This is probably a good opportunity to use READ_ONCE/WRITE_ONCE for
this variable that can be modified and read concurrently.
Alternatively I can fix up all three locations in a follow-on patch.
No concerns with adding the getsockopt itself.
> case PACKET_VERSION:
> val = po->tp_version;
> break;
> --
> 2.39.2
>
On 2024/3/8 19:43, Willem de Bruijn wrote:
> Juntong Deng wrote:
>> Currently getsockopt does not support PACKET_COPY_THRESH,
>> and we are unable to get the value of PACKET_COPY_THRESH
>> socket option through getsockopt.
>>
>> This patch adds getsockopt support for PACKET_COPY_THRESH.
>>
>> Signed-off-by: Juntong Deng <[email protected]>
>> ---
>> net/packet/af_packet.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
>> index 0db31ca4982d..65042edd1a97 100644
>> --- a/net/packet/af_packet.c
>> +++ b/net/packet/af_packet.c
>> @@ -4090,6 +4090,9 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
>> case PACKET_VNET_HDR_SZ:
>> val = READ_ONCE(po->vnet_hdr_sz);
>> break;
>> + case PACKET_COPY_THRESH:
>> + val = pkt_sk(sk)->copy_thresh;
>> + break;
>
> This is probably a good opportunity to use READ_ONCE/WRITE_ONCE for
> this variable that can be modified and read concurrently.
>
> Alternatively I can fix up all three locations in a follow-on patch.
>
> No concerns with adding the getsockopt itself.
>
>> case PACKET_VERSION:
>> val = po->tp_version;
>> break;
>> --
>> 2.39.2
>>
>
>
Thanks for reviewing.
So, do I need to send PATCH V2 to add READ_ONCE?
Or do you want you to use a follow-on patch to fix all three locations
at once?
On Fri, Mar 8, 2024 at 7:43 PM Willem de Bruijn
<[email protected]> wrote:
>
> Juntong Deng wrote:
> > Currently getsockopt does not support PACKET_COPY_THRESH,
> > and we are unable to get the value of PACKET_COPY_THRESH
> > socket option through getsockopt.
> >
> > This patch adds getsockopt support for PACKET_COPY_THRESH.
> >
> > Signed-off-by: Juntong Deng <[email protected]>
> > ---
> > net/packet/af_packet.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> > index 0db31ca4982d..65042edd1a97 100644
> > --- a/net/packet/af_packet.c
> > +++ b/net/packet/af_packet.c
> > @@ -4090,6 +4090,9 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
> > case PACKET_VNET_HDR_SZ:
> > val = READ_ONCE(po->vnet_hdr_sz);
> > break;
> > + case PACKET_COPY_THRESH:
> > + val = pkt_sk(sk)->copy_thresh;
> > + break;
>
> This is probably a good opportunity to use READ_ONCE/WRITE_ONCE for
> this variable that can be modified and read concurrently.
>
> Alternatively I can fix up all three locations in a follow-on patch.
Yes, variables which can be set through setsockopt related functions
have a chance to be modified when another process does read it.
The patch you mentioned goes like this, I think:
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 0db31ca4982d..b598dcafe441 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2318,7 +2318,7 @@ static int tpacket_rcv(struct sk_buff *skb,
struct net_device *dev,
}
if (po->tp_version <= TPACKET_V2) {
if (macoff + snaplen > po->rx_ring.frame_size) {
- if (po->copy_thresh &&
+ if (READ_ONCE(po->copy_thresh) &&
atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
if (skb_shared(skb)) {
copy_skb = skb_clone(skb, GFP_ATOMIC);
@@ -3836,7 +3836,7 @@ packet_setsockopt(struct socket *sock, int
level, int optname, sockptr_t optval,
if (copy_from_sockptr(&val, optval, sizeof(val)))
return -EFAULT;
- pkt_sk(sk)->copy_thresh = val;
+ WRITE_ONCE(pkt_sk(sk)->copy_thresh, val);
return 0;
}
case PACKET_VERSION:
diff --git a/net/packet/diag.c b/net/packet/diag.c
index b3bd2f6c2bf7..47f69f3dbf73 100644
--- a/net/packet/diag.c
+++ b/net/packet/diag.c
@@ -17,7 +17,7 @@ static int pdiag_put_info(const struct packet_sock
*po, struct sk_buff *nlskb)
pinfo.pdi_index = po->ifindex;
pinfo.pdi_version = po->tp_version;
pinfo.pdi_reserve = po->tp_reserve;
- pinfo.pdi_copy_thresh = po->copy_thresh;
+ pinfo.pdi_copy_thresh = READ_ONCE(po->copy_thresh);
pinfo.pdi_tstamp = READ_ONCE(po->tp_tstamp);
pinfo.pdi_flags = 0;
Thanks,
Jason
>
> No concerns with adding the getsockopt itself.
>
> > case PACKET_VERSION:
> > val = po->tp_version;
> > break;
> > --
> > 2.39.2
> >
>
>
>