[ovs-dev] [PATCH ovn] Replace ds_put_* evaluating to constant expressions

Anton Ivanov anton.ivanov at cambridgegreys.com
Wed Sep 9 11:44:47 UTC 2020


On 09/09/2020 12:20, Ilya Maximets wrote:
> On 9/9/20 11:02 AM, anton.ivanov at cambridgegreys.com wrote:
>> From: Anton Ivanov <anton.ivanov at cambridgegreys.com>
>>
>> Replaces ds_put_cstr and ds_put_format which evaluate to
>> constant expressions with string constants
>>
>> Signed-off-by: Anton Ivanov <anton.ivanov at cambridgegreys.com>
>> ---
> 
> Hi.  Thanks for the fix!
> 
> One general comment to almost all of your patches:
> Please, use the following format for the patch subject:
>    <area>: Summary.
> i.e. add an <area>: part that should represent a piece of code this patch
> is targeted to.  For example, it should be 'ovn-northd:' for this patch.
> And it's also better to end the patch subject with a period.  You already
> starting the summary with a capital letter, so this  part is fine.
> 
> https://docs.ovn.org/en/latest/internals/contributing/submitting-patches.html#email-subject
> 
> Some comments for the patch inline.

Cool. I will address them in the next revision. I found one more case of 
constant format as well.

> 
> Best regards, Ilya Maximets.
> 
>>   northd/ovn-northd.c | 56 ++++++++++++++++++++++-----------------------
>>   1 file changed, 28 insertions(+), 28 deletions(-)
>>
>> diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
>> index 3de71612b..c681d5cbf 100644
>> --- a/northd/ovn-northd.c
>> +++ b/northd/ovn-northd.c
>> @@ -1928,6 +1928,8 @@ update_dynamic_addresses(struct dynamic_address_update *update)
>>   
>>       struct ds new_addr = DS_EMPTY_INITIALIZER;
>>       ds_put_format(&new_addr, ETH_ADDR_FMT, ETH_ADDR_ARGS(mac));
>> +
>> +
> 
> This is totally unrelated and not needed.
> 
>>       ipam_insert_mac(&mac, true);
>>   
>>       if (ip4) {
>> @@ -6950,24 +6952,24 @@ build_lswitch_flows(struct hmap *datapaths, struct hmap *ports,
>>           struct ds action = DS_EMPTY_INITIALIZER;
>>   
>>           ds_clear(&match);
> 
> No need to clear.
> 
>> -        ds_put_cstr(&match, "udp.dst == 53");
>> +        const char *dns_match = "udp.dst == 53";
> 
> It might be better to just pass this string directly  to the ovn_lflow_add.
> 
>>           ds_put_format(&action,
>>                         REGBIT_DNS_LOOKUP_RESULT" = dns_lookup(); next;");
>>           ovn_lflow_add(lflows, od, S_SWITCH_IN_DNS_LOOKUP, 100,
>> -                      ds_cstr(&match), ds_cstr(&action));
>> +                      dns_match, ds_cstr(&action));
>>           ds_clear(&action);
>> -        ds_put_cstr(&match, " && "REGBIT_DNS_LOOKUP_RESULT);
>> -        ds_put_format(&action, "eth.dst <-> eth.src; ip4.src <-> ip4.dst; "
>> +
>> +        const char *dns_match2 = "udp.dst == 53 && "REGBIT_DNS_LOOKUP_RESULT;
> 
> Please, declare a single variable once for both cases at the top of the block.
> 
>> +        const char *dns_action = "eth.dst <-> eth.src; ip4.src <-> ip4.dst; "
> 
> And this block is not big, so , please, declare this variable at the top of the
> block too.
> 
>>                         "udp.dst = udp.src; udp.src = 53; outport = inport; "
>> -                      "flags.loopback = 1; output;");
>> +                      "flags.loopback = 1; output;";
>>           ovn_lflow_add(lflows, od, S_SWITCH_IN_DNS_RESPONSE, 100,
>> -                      ds_cstr(&match), ds_cstr(&action));
>> -        ds_clear(&action);
>> -        ds_put_format(&action, "eth.dst <-> eth.src; ip6.src <-> ip6.dst; "
>> +                      dns_match2, dns_action);
>> +        dns_action = "eth.dst <-> eth.src; ip6.src <-> ip6.dst; "
>>                         "udp.dst = udp.src; udp.src = 53; outport = inport; "
>> -                      "flags.loopback = 1; output;");
>> +                      "flags.loopback = 1; output;";
>>           ovn_lflow_add(lflows, od, S_SWITCH_IN_DNS_RESPONSE, 100,
>> -                      ds_cstr(&match), ds_cstr(&action));
>> +                      dns_match2, dns_action);
>>           ds_destroy(&action);
>>       }
>>   
>> @@ -7839,10 +7841,10 @@ add_ecmp_symmetric_reply_flows(struct hmap *lflows,
>>                               &st_route->header_);
>>   
>>       ds_clear(&actions);
> 
> No more need to clear.
> 
>> -    ds_put_cstr(&actions, "eth.dst = ct_label.ecmp_reply_eth; next;");
>> +    const char *action = "eth.dst = ct_label.ecmp_reply_eth; next;";
> 
> It might be better to just pass this string directly  to the function below,
> i.e. without any intermediate variables.
> 
>>       ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_ARP_RESOLVE,
>>                               200, ds_cstr(&ecmp_reply),
>> -                            ds_cstr(&actions), &st_route->header_);
>> +                            action, &st_route->header_);
>>   }
>>   
>>   static void
>> @@ -8734,9 +8736,9 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>>   
>>           /* TTL discard */
>>           ds_clear(&match);
> 
> No more need to clear.
> 
>> -        ds_put_cstr(&match, "ip4 && ip.ttl == {0, 1}");
>> +        const char *ttl_match = "ip4 && ip.ttl == {0, 1}";
> 
> Ditto.
> 
>>           ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_INPUT, 30,
>> -                      ds_cstr(&match), "drop;");
>> +                      ttl_match, "drop;");
>>   
>>           /* Pass other traffic not already handled to the next table for
>>            * routing. */
>> @@ -8778,14 +8780,13 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>>               ds_put_cstr(&match, " && icmp4.type == 8 && icmp4.code == 0");
>>   
>>               ds_clear(&actions);
> 
> No more need to clear.
> 
>> -            ds_put_format(&actions,
>> -                "ip4.dst <-> ip4.src; "
>> -                "ip.ttl = 255; "
>> -                "icmp4.type = 0; "
>> -                "flags.loopback = 1; "
>> -                "next; ");
>> +            const char * icmp_actions = "ip4.dst <-> ip4.src; "
>> +                                    "ip.ttl = 255; "
>> +                                    "icmp4.type = 0; "
>> +                                    "flags.loopback = 1; "
>> +                                    "next; ";
> 
> Since you're shifting these lines please align them with the first one,
> i.e. 4 more spaces to the right.
> 
> BTW, it's kind of inconsistent that you're shifting these lines here and
> not shifting in a change below.  It might make sense to not shift at all.
> 
>>               ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_INPUT, 90,
>> -                                    ds_cstr(&match), ds_cstr(&actions),
>> +                                    ds_cstr(&match), icmp_actions,
>>                                       &op->nbrp->header_);
>>           }
>>   
>> @@ -9184,14 +9185,14 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>>               ds_put_cstr(&match, " && icmp6.type == 128 && icmp6.code == 0");
>>   
>>               ds_clear(&actions);
> 
> No more need to clear.
> 
>> -            ds_put_cstr(&actions,
>> +            const char *lrp_actions =
>>                           "ip6.dst <-> ip6.src; "
>>                           "ip.ttl = 255; "
>>                           "icmp6.type = 129; "
>>                           "flags.loopback = 1; "
>> -                        "next; ");
>> +                        "next; ";
>>               ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_INPUT, 90,
>> -                                    ds_cstr(&match), ds_cstr(&actions),
>> +                                    ds_cstr(&match), lrp_actions,
>>                                       &op->nbrp->header_);
>>           }
>>   
>> @@ -10449,13 +10450,12 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
>>                                         REG_NEXT_HOP_IPV4 " == %s",
>>                                         peer->json_key, vip);
>>   
>> -                        ds_clear(&actions);
>> -                        ds_put_format(&actions,
>> -                                      "eth.dst = 00:00:00:00:00:00; next;");
>> +                        const char *arp_actions =
>> +                                      "eth.dst = 00:00:00:00:00:00; next;";
>>                           ovn_lflow_add_with_hint(lflows, peer->od,
>>                                                   S_ROUTER_IN_ARP_RESOLVE, 100,
>>                                                   ds_cstr(&match),
>> -                                                ds_cstr(&actions),
>> +                                                arp_actions,
>>                                                   &op->nbsp->header_);
>>                           break;
>>                       }
>>
> 
> 


-- 
Anton R. Ivanov
Cambridgegreys Limited. Registered in England. Company Number 10273661
https://www.cambridgegreys.com/


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