netdev - Re: [PATCH bpf 2/3] devmap: Add missing bulk queue free

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Date:   Fri, 14 Jun 2019 22:03:57 +0900
From:   Toshiaki Makita <toshiaki.makita1@...il.com>
To:     Jesper Dangaard Brouer <brouer@...hat.com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        netdev@...r.kernel.org, xdp-newbies@...r.kernel.org,
        bpf@...r.kernel.org, "Michael S. Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        David Ahern <dsahern@...il.com>
Subject: Re: [PATCH bpf 2/3] devmap: Add missing bulk queue free

On 19/06/14 (金) 20:58:06, Jesper Dangaard Brouer wrote:
> On Fri, 14 Jun 2019 17:20:14 +0900
> Toshiaki Makita <toshiaki.makita1@...il.com> wrote:
> 
>> dev_map_free() forgot to free bulk queue when freeing its entries.
>>
>> Fixes: 5d053f9da431 ("bpf: devmap prepare xdp frames for bulking")
>> Signed-off-by: Toshiaki Makita <toshiaki.makita1@...il.com>
>> ---
>>   kernel/bpf/devmap.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
>> index e001fb1..a126d95 100644
>> --- a/kernel/bpf/devmap.c
>> +++ b/kernel/bpf/devmap.c
>> @@ -186,6 +186,7 @@ static void dev_map_free(struct bpf_map *map)
>>   		if (!dev)
>>   			continue;
>>   
>> +		free_percpu(dev->bulkq);
>>   		dev_put(dev->dev);
>>   		kfree(dev);
>>   	}
> 
> Do we need to call need to call dev_map_flush_old() before
> free_percpu(dev->bulkq) ?
> 
> Looking the code, I guess this is not needed as, above we are ensuring
> all pending flush operations have completed.

My understanding is the same. The code waits for NAPI to flush the 
queue, so no need for dev_map_flush_old().

> 
> Acked-by: Jesper Dangaard Brouer <brouer@...hat.com>

Thanks!

Toshiaki Makita