Re: [PATCH v2] net: thunderx: rework mac addresses list to u64 array

Gustavo A. R. Silva
2018-04-06T11:47:31Z

On 04/06/2018 06:43 AM, Vadim Lomovtsev wrote:
> Hi Gustavo,
>
> On Fri, Apr 06, 2018 at 06:36:28AM -0500, Gustavo A. R. Silva wrote:
>> Hi Vadim,
>>
>> On 04/06/2018 06:14 AM, Vadim Lomovtsev wrote:
>>> From: Vadim Lomovtsev <Vadim.Lomovtsev@cavium.com>
>>>
>>> It is too expensive to pass u64 values via linked list, instead
>>> allocate array for them by overall number of mac addresses from netdev.
>>>
>>> This eventually removes multiple kmalloc() calls, aviod memory
>>> fragmentation and allow to put single null check on kmalloc
>>> return value in order to prevent a potential null pointer dereference.
>>>
>>> Addresses-Coverity-ID: 1467429 ("Dereference null return value")
>>> Fixes: 37c3347eb247 ("net: thunderx: add ndo_set_rx_mode callback implementation for VF")
>>
>> It'd be nice if you add:
>>
>> Reported-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>
> Ok, I could do that.
>
> Just to explain .. I didn't do it yet since I get such report from
> Dan Carpenter intially (https://www.spinics.net/lists/linux-kernel-janitors/msg40720.html)
> and was working on it when found you patches, so then asking you to give
> me some time to prepare and test update to driver.
>

Oh I got it. Not big deal. I think in this case you should add Dan's
Reported-by instead.

BTW nice patch. :)

Thanks
--
Gustavo

> So would it be acceptable put two tags 'Reported-by:' then ?
>
> WBR,
> Vadim
>
>>
>> Thanks
>> --
>> Gustavo
>>
>>> Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev@cavium.com>
>>> ---
>>> Changes from v1 to v2:
>>> - C99 syntax: update xcast_addr_list struct field mc[0] -> mc[];
>>>
>>> ---
>>> drivers/net/ethernet/cavium/thunder/nic.h | 7 +-----
>>> drivers/net/ethernet/cavium/thunder/nicvf_main.c | 28 +++++++++---------------
>>> 2 files changed, 11 insertions(+), 24 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/cavium/thunder/nic.h b/drivers/net/ethernet/cavium/thunder/nic.h
>>> index 5fc46c5a4f36..448d1fafc827 100644
>>> --- a/drivers/net/ethernet/cavium/thunder/nic.h
>>> +++ b/drivers/net/ethernet/cavium/thunder/nic.h
>>> @@ -265,14 +265,9 @@ struct nicvf_drv_stats {
>>> struct cavium_ptp;
>>> -struct xcast_addr {
>>> - struct list_head list;
>>> - u64 addr;
>>> -};
>>> -
>>> struct xcast_addr_list {
>>> - struct list_head list;
>>> int count;
>>> + u64 mc[];
>>> };
>>> struct nicvf_work {
>>> diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
>>> index 1e9a31fef729..a26d8bc92e01 100644
>>> --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
>>> +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
>>> @@ -1929,7 +1929,7 @@ static void nicvf_set_rx_mode_task(struct work_struct *work_arg)
>>> work.work);
>>> struct nicvf *nic = container_of(vf_work, struct nicvf, rx_mode_work);
>>> union nic_mbx mbx = {};
>>> - struct xcast_addr *xaddr, *next;
>>> + u8 idx = 0;
>>> if (!vf_work)
>>> return;
>>> @@ -1956,16 +1956,10 @@ static void nicvf_set_rx_mode_task(struct work_struct *work_arg)
>>> /* check if we have any specific MACs to be added to PF DMAC filter */
>>> if (vf_work->mc) {
>>> /* now go through kernel list of MACs and add them one by one */
>>> - list_for_each_entry_safe(xaddr, next,
>>> - &vf_work->mc->list, list) {
>>> + for (idx = 0; idx < vf_work->mc->count; idx++) {
>>> mbx.xcast.msg = NIC_MBOX_MSG_ADD_MCAST;
>>> - mbx.xcast.data.mac = xaddr->addr;
>>> + mbx.xcast.data.mac = vf_work->mc->mc[idx];
>>> nicvf_send_msg_to_pf(nic, &mbx);
>>> -
>>> - /* after receiving ACK from PF release memory */
>>> - list_del(&xaddr->list);
>>> - kfree(xaddr);
>>> - vf_work->mc->count--;
>>> }
>>> kfree(vf_work->mc);
>>> }
>>> @@ -1996,17 +1990,15 @@ static void nicvf_set_rx_mode(struct net_device *netdev)
>>> mode |= BGX_XCAST_MCAST_FILTER;
>>> /* here we need to copy mc addrs */
>>> if (netdev_mc_count(netdev)) {
>>> - struct xcast_addr *xaddr;
>>> -
>>> - mc_list = kmalloc(sizeof(*mc_list), GFP_ATOMIC);
>>> - INIT_LIST_HEAD(&mc_list->list);
>>> + mc_list = kmalloc(sizeof(*mc_list) +
>>> + sizeof(u64) * netdev_mc_count(netdev),
>>> + GFP_ATOMIC);
>>> + if (unlikely(!mc_list))
>>> + return;
>>> + mc_list->count = 0;
>>> netdev_hw_addr_list_for_each(ha, &netdev->mc) {
>>> - xaddr = kmalloc(sizeof(*xaddr),
>>> - GFP_ATOMIC);
>>> - xaddr->addr =
>>> + mc_list->mc[mc_list->count] =
>>> ether_addr_to_u64(ha->addr);
>>> - list_add_tail(&xaddr->list,
>>> - &mc_list->list);
>>> mc_list->count++;
>>> }
>>> }
>>>