On Wed, Mar 18, 2020 at 04:53:27PM +0100, Ilya Maximets wrote: > On 3/18/20 4:36 PM, Ben Pfaff wrote: > > On Wed, Mar 18, 2020 at 08:34:16AM -0700, William Tu wrote: > >> On Wed, Mar 18, 2020 at 7:59 AM Ilya Maximets <i.maxim...@ovn.org> wrote: > >>> > >>> On 3/18/20 12:31 AM, William Tu wrote: > >>>> Coverity CID 279497 reports "Operands don't affect result". > >>>> Because flow->ct_state is uint8_t and DP_NETDEV_CS_UNSUPPORTED_MASK > >>>> is '0xffffff00'. So remove the statement. > >>>> > >>>> Cc: Usman Ansari <uans...@vmware.com> > >>>> Signed-off-by: William Tu <u9012...@gmail.com> > >>>> --- > >>>> lib/dpif-netdev.c | 4 ---- > >>>> 1 file changed, 4 deletions(-) > >>>> > >>>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c > >>>> index a798db45d9cb..0e2678d002d5 100644 > >>>> --- a/lib/dpif-netdev.c > >>>> +++ b/lib/dpif-netdev.c > >>>> @@ -3224,10 +3224,6 @@ dpif_netdev_flow_from_nlattrs(const struct nlattr > >>>> *key, uint32_t key_len, > >>>> return EINVAL; > >>>> } > >>>> > >>>> - if (flow->ct_state & DP_NETDEV_CS_UNSUPPORTED_MASK) { > >>>> - return EINVAL; > >>>> - } > >>>> - > >>> > >>> I'm not sure if we need to remove this. This code doesn't make any harm > >>> and most likely compiled out. I agree that it doesn't change any logic > >>> in this function, but in case someone will try to add new flags or change > >>> the type of ct_state we will be safe and will reject all the unknown > >>> flags. > >>> Without this code we'll have to catch this case somehow on code review and > >>> re-introduce this check or implement missing functionality. > >>> > >>> One more thing is that DP_NETDEV_CS_UNSUPPORTED_MASK definition becomes > >>> unused and should be removed along with _SUPPORTED_MASK. > >> > >> Good point. > >> > >>> > >>> So, I'd rather not touch this and just mark this code as OK for coverity > >>> scanner. But if you want to remove, please, clean up other parts and > >>> add a build assert for the ct_state size and flags, so any disruptive > >>> change > >>> will be caught by the developer of this change. > >>> > >> OK thanks! > >> Let's keep this code block as it is now. > > > > I was surprised to hear that it doesn't have any effect. Adding a > > comment might be helpful. > > > > DP_NETDEV_CS_UNSUPPORTED_MASK was introduced at the time when dpif-netdev > didn't > support NAT. After the NAT support implementation in commit > 4cddb1f0d837 ("dpdk: Parse NAT netlink for userspace datapath.") this mask is > just > a zero in the lowest 8 bits, i.e. all current flags are supported. > > I'm not sure why it's casted to uint32_t, though, or why flow->ct_state is 8 > bits > only. packets.h has similar mask and it's casted to uint32_t too. The main > concern > here is that it seems like ct_state is 32bit in netlink. That produces > misunderstanding > and makes me nervous about potential issues. > > flow->ct_state is 8 bits long and mask is zero there, so this 'if' statement > is > always false.
Oh, I understand the reason, but from glancing at the code it's not obvious. _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev