[PATCH 06/12] net/rtdev: ensure per-device skbs get mapped at registration

Philippe Gerum rpm at xenomai.org
Wed Feb 6 10:02:37 CET 2019


On 1/24/19 7:24 PM, Jan Kiszka wrote:
> On 24.01.19 16:34, Philippe Gerum wrote:
>> This patch works around a regression introduced by #74464ee37d0,
>> causing a new device's skbs not to be passed to its ->map_rtskb()
>> handler when registered, breaking further DMA inits in the driver.
>>
>> Signed-off-by: Philippe Gerum <rpm at xenomai.org>
>> ---
>>   kernel/drivers/net/stack/rtdev.c | 37 +++++++++++++++++++++++---------
>>   1 file changed, 27 insertions(+), 10 deletions(-)
>>
>> diff --git a/kernel/drivers/net/stack/rtdev.c
>> b/kernel/drivers/net/stack/rtdev.c
>> index 631ca1804..286d08cb1 100644
>> --- a/kernel/drivers/net/stack/rtdev.c
>> +++ b/kernel/drivers/net/stack/rtdev.c
>> @@ -45,6 +45,7 @@ struct rtnet_device        
>> *rtnet_devices[MAX_RT_DEVICES];
>>   static struct rtnet_device  *loopback_device;
>>   static DEFINE_RTDM_LOCK(rtnet_devices_rt_lock);
>>   static LIST_HEAD(rtskb_mapped_list);
>> +static LIST_HEAD(rtskb_mapwait_list);
>>     LIST_HEAD(event_hook_list);
>>   DEFINE_MUTEX(rtnet_devices_nrt_lock);
>> @@ -459,8 +460,12 @@ int rtdev_map_rtskb(struct rtskb *skb)
>>       }
>>       }
>>   -    if (!err && skb->buf_dma_addr != RTSKB_UNMAPPED)
>> -    list_add(&skb->entry, &rtskb_mapped_list);
>> +    if (!err) {
>> +        if (skb->buf_dma_addr != RTSKB_UNMAPPED)
>> +            list_add(&skb->entry, &rtskb_mapped_list);
>> +        else
>> +            list_add(&skb->entry, &rtskb_mapwait_list);
>> +    }
>>         mutex_unlock(&rtnet_devices_nrt_lock);
>>   @@ -471,19 +476,31 @@ int rtdev_map_rtskb(struct rtskb *skb)
>>     static int rtdev_map_all_rtskbs(struct rtnet_device *rtdev)
>>   {
>> -    struct rtskb *skb;
>> -    int err = 0;
>> +    struct rtskb *skb, *n;
>> +    int err;
>>         if (!rtdev->map_rtskb)
>> -    return 0;
>> +        return 0;
>>   -    list_for_each_entry(skb, &rtskb_mapped_list, entry) {
>> -    err = rtskb_map(rtdev, skb);
>> -    if (err)
>> -       break;
>> +    if (!list_empty(&rtskb_mapped_list)) {
> 
> Why this extra check? list_for_each_entry should just do nothing if the
> list is empty.
> 
>> +        list_for_each_entry(skb, &rtskb_mapped_list, entry) {
>> +            err = rtskb_map(rtdev, skb);
>> +            if (err)
>> +                return err;
>> +        }
>>       }
>>   -    return err;
>> +    if (!list_empty(&rtskb_mapwait_list)) {
> 
> Same here.
> 
>> +        list_for_each_entry_safe(skb, n, &rtskb_mapwait_list, entry) {
>> +            err = rtskb_map(rtdev, skb);
>> +            if (err)
>> +                return err;
>> +            list_del(&skb->entry);
>> +            list_add(&skb->entry, &rtskb_mapped_list);
>> +        }
>> +    }
>> +
>> +    return 0;
>>   }
>>    
> 
> Style mix: Eventually, we should switch all RTnet code to kernel style.
> For now, we have 4-space-indention, and we should keep it until then.
> Mixing things will only make it more messy.
> 

There is a massive commit [1] pending in my queue fixing RTnet wrt
coding style, which I'm not going to paste here. This is the result of
filtering the code through scripts/Lindent basically.

Would you agree on merging such kind of commit into RTnet? If so, the
vlan and multicast support I'm currently adapting from Gilles' past work
should go on top of such changes.

[1]
https://lab.xenomai.org/xenomai-rpm.git/commit/?h=for-upstream/next&id=d6cab66ddaf4e01cd9166dc530acc60c5b3bd3c2

-- 
Philippe.



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