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Date: Tue, 30 Dec 2014 05:57:56 -0800
From: roopa <roopa@...ulusnetworks.com>
To: Scott Feldman <sfeldma@...il.com>
CC: Netdev <netdev@...r.kernel.org>, shemminger@...tta.com,
"vyasevic@...hat.com" <vyasevic@...hat.com>,
Wilson kok <wkok@...ulusnetworks.com>
Subject: Re: [PATCH 5/6] bridge: new function to pack vlans using both IFLA_BRIDGE_VLAN_INFO
and IFLA_BRIDGE_VLAN_RANGE_INFO
On 12/30/14, 12:04 AM, Scott Feldman wrote:
> On Mon, Dec 29, 2014 at 9:31 PM, roopa <roopa@...ulusnetworks.com> wrote:
>> On 12/29/14, 3:25 PM, Scott Feldman wrote:
>>> On Mon, Dec 29, 2014 at 1:05 PM, <roopa@...ulusnetworks.com> wrote:
>>>> From: Roopa Prabhu <roopa@...ulusnetworks.com>
>>>>
>>>> This patch adds new function to compress vlans into ranges.
>>>> Vlans are compressed into ranges only if the fill request is called with
>>>> RTEXT_FILTER_BRVLAN_COMPRESSED in filtermask.
>>>>
>>>> Old vlan packing code is moved to a new function and continues to be
>>>> called when filter_mask is RTEXT_FILTER_BRVLAN
>>>>
>>>> Signed-off-by: Wilson kok <wkok@...ulusnetworks.com>
>>>> Signed-off-by: Roopa Prabhu <roopa@...ulusnetworks.com>
>>>> ---
>>>> net/bridge/br_netlink.c | 157
>>>> +++++++++++++++++++++++++++++++++++++++++------
>>>> 1 file changed, 137 insertions(+), 20 deletions(-)
>>>>
>>>> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
>>>> index 4c47ba0..16bdd5a 100644
>>>> --- a/net/bridge/br_netlink.c
>>>> +++ b/net/bridge/br_netlink.c
>>>> @@ -67,6 +67,133 @@ static int br_port_fill_attrs(struct sk_buff *skb,
>>>> return 0;
>>>> }
>>>>
>>>> +static int br_fill_ifvlaninfo_bitmap(struct sk_buff *skb,
>>>> + const unsigned long *vlan_bmp, u16
>>>> flags)
>>>> +{
>>>> + struct bridge_vlan_range_info vinfo_range;
>>>> + struct bridge_vlan_info vinfo;
>>>> + u16 vid, start = 0, end = 0;
>>> One per line?
>> ack
>>
>>>> + u16 pvid;
>>> Aren't you getting an "unused" compile warning on this ^^^?
>> will double check..
>>
>>>> +
>>>> + /* handle the untagged */
>>> This comment ^^^ doesn't make sense here.
>>>
>>>> + for_each_set_bit(vid, vlan_bmp, VLAN_N_VID) {
>>>> + if (start == 0) {
>>>> + start = vid;
>>>> + end = vid;
>>>> + }
>>>> + if ((vid - end) > 1) {
>>>> + memset(&vinfo_range, 0, sizeof(vinfo_range));
>>>> + vinfo_range.flags |= flags;
>>>> + vinfo_range.vid = start;
>>>> + vinfo_range.vid_end = end;
>>>> + if (nla_put(skb, IFLA_BRIDGE_VLAN_RANGE_INFO,
>>>> + sizeof(vinfo_range), &vinfo_range))
>>>> + goto nla_put_failure;
>>>> + start = vid;
>>>> + end = vid;
>>>> + } else {
>>>> + end = vid;
>>>> + }
>>>> + }
>>> What happens with this set {1-10, 12, 20-25, 30}? On vid 12, will
>>> that put a VLAN_RANGE_INFO with start=end=12? Seems strange to use
>>> RANGE_INFO for single vlan.
>>>
>>> Can the algorithm be simplified? Maybe there are other examples in
>>> the kernel of finding ranges/singles from a bitmap we could borrow
>>> code from?
>> let me see...
>>
>>>> + if (start != 0 && end != 0) {
>>>> + if (start != end) {
>>>> + memset(&vinfo_range, 0, sizeof(vinfo_range));
>>>> + vinfo_range.flags |= flags;
>>>> + vinfo_range.vid = start;
>>>> + vinfo_range.vid_end = end;
>>>> + if (nla_put(skb, IFLA_BRIDGE_VLAN_RANGE_INFO,
>>>> + sizeof(vinfo_range), &vinfo_range))
>>>> + goto nla_put_failure;
>>>> + } else {
>>>> + memset(&vinfo, 0, sizeof(vinfo));
>>>> + vinfo.flags |= flags;
>>>> + vinfo.vid = start;
>>>> + if (nla_put(skb, IFLA_BRIDGE_VLAN_INFO,
>>>> + sizeof(vinfo), &vinfo))
>>>> + goto nla_put_failure;
>>> How many IFLA_BRIDGE_VLAN_INFOs can you fit into skb? It seems the
>>> worst case is you'll have 4094/2 = 2047 VLAN_INFOs if using all
>>> even-numbered vids, for example. Will that fit? I guess the original
>>> code had the same concern...wonder if anyone checked this worst-case?
>>
>> I will check this again. Remember doing worst case tests for setlinks. will
>> get back with some worst cases tests in the next submission.
>>>
>>>> + }
>>>> + }
>>>> +
>>>> +nla_put_failure:
>>>> + return -EMSGSIZE;
>>>> +}
>>>> +
>>>> +static int br_fill_ifvlaninfo_compressed(struct sk_buff *skb,
>>>> + const struct net_port_vlans *pv)
>>>> +{
>>>> + unsigned long vlan_bmp_copy[BR_VLAN_BITMAP_LEN];
>>>> + unsigned long untagged_bmp_copy[BR_VLAN_BITMAP_LEN];
>>> Lots of automatic space on the stack...can you use dynamic mem
>>> (kzalloc) for these?
>> Let me see. Or make it a static global ?
> Static global would be bad news for multiple threads doing a vlan fill.
They are all under rtnl_lock today. In any case, I do plan to change it
to kzalloc in its current place.
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