[dpdk-stable] [dpdk-dev] [PATCH] malloc: fix memory element size in case of padding

[Burakov, Anatoly]

On 26-Nov-19 1:45 PM, Thomas Monjalon wrote:
> 26/11/2019 14:39, Xueming(Steven) Li:
>>
>>> -----Original Message-----
>>> From: Thomas Monjalon <thomas at monjalon.net>
>>> Sent: Tuesday, November 26, 2019 9:30 PM
>>> To: Burakov, Anatoly <anatoly.burakov at intel.com>
>>> Cc: Xueming(Steven) Li <xuemingl at mellanox.com>; dev at dpdk.org; Asaf
>>> Penso <asafp at mellanox.com>; stable at dpdk.org;
>>> david.marchand at redhat.com
>>> Subject: Re: [dpdk-dev] [PATCH] malloc: fix memory element size in case of
>>> padding
>>>
>>> 26/11/2019 13:57, Burakov, Anatoly:
>>>> On 25-Nov-19 11:24 PM, Thomas Monjalon wrote:
>>>>> 21/11/2019 16:14, Burakov, Anatoly:
>>>>>> On 21-Nov-19 2:25 PM, Xueming Li wrote:
>>>>>>> This patch fixes wrong inner memory element size when joining two
>>>>>>> elements.
>>>>>>>
>>>>>>> Fixes: af75078fece3 ("first public release")
>>>>>>> Cc: stable at dpdk.org
>>>>>>>
>>>>>>> Signed-off-by: Xueming Li <xuemingl at mellanox.com>
>>>>>>> ---
>>>>>>> --- a/lib/librte_eal/common/malloc_elem.c
>>>>>>> +++ b/lib/librte_eal/common/malloc_elem.c
>>>>>>> @@ -487,6 +487,10 @@ join_elem(struct malloc_elem *elem1, struct
>>> malloc_elem *elem2)
>>>>>>>     	else
>>>>>>>     		elem1->heap->last = elem1;
>>>>>>>     	elem1->next = next;
>>>>>>> +	if (elem1->pad) {
>>>>>>> +		struct malloc_elem *inner = RTE_PTR_ADD(elem1, elem1-
>>>> pad);
>>>>>>> +		inner->size = elem1->size - elem1->pad;
>>>>>>> +	}
>>>>>>>     }
>>>>>>
>>>>>> Reviewed-by: Anatoly Burakov <anatoly.burakov at intel.com>
>>>>>
>>>>> I don't understand this patch.
>>>>> The variable inner is never used.
>>>>> What am I missing?
>>>>>
>>>>
>>>> For padded elements, malloc element has two headers - the "outer"
>>>> header with empty space after it, and the "inner" header, after which
>>>> the user memory actually starts. This makes it so that, when joining
>>>> elements, if the outer element had a pad, we also update the inner
>>> element size to match.
>>>
>>> Where the variable "inner" is used in this function?

Right on the next line after it is created :)

-- 
Thanks,
Anatoly