[dpdk-stable] [PATCH v7 1/1] fbarray: fix duplicated fbarray file in secondary

[Yasufumi Ogawa]

Hi David,

Sorry for slow reply.

On 2019/11/14 21:27, David Marchand wrote:
> On Thu, Nov 14, 2019 at 12:42 PM Yasufumi Ogawa <yasufum.o at gmail.com> wrote:
>>
>> On 2019/11/14 2:01, Burakov, Anatoly wrote:
>>> On 13-Nov-19 9:43 PM, yasufum.o at gmail.com wrote:
>>>> From: Yasufumi Ogawa <ogawa.yasufumi at lab.ntt.co.jp>
>>>>
>>>> In secondary_msl_create_walk(), it creates a file for fbarrays with its
>>>> PID for reserving unique name among secondary processes. However, it
>>>> does not work if several secondaries run as app containers because each
>>>> of containerized secondary has PID 1, and failed to reserve unique name
>>>> other than first one. To reserve unique name in each of containers, use
>>>> hostname in addition to PID.
>>>>
>>>> Cc: stable at dpdk.org
>>>>
>>>> Signed-off-by: Yasufumi Ogawa <yasufum.o at gmail.com>
>>>> ---
>>>>    lib/librte_eal/linux/eal/eal_memalloc.c | 16 +++++++++++++---
>>>>    1 file changed, 13 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/lib/librte_eal/linux/eal/eal_memalloc.c
>>>> b/lib/librte_eal/linux/eal/eal_memalloc.c
>>>> index af6d0d023..11de6d4d6 100644
>>>> --- a/lib/librte_eal/linux/eal/eal_memalloc.c
>>>> +++ b/lib/librte_eal/linux/eal/eal_memalloc.c
>>>> @@ -1365,6 +1365,12 @@ secondary_msl_create_walk(const struct
>>>> rte_memseg_list *msl,
>>>>        struct rte_memseg_list *primary_msl, *local_msl;
>>>>        char name[PATH_MAX];
>>>>        int msl_idx, ret;
>>>> +    char hostname[HOST_NAME_MAX+1] = { 0 };
>>>> +    /* filename of secondary's fbarray is defined such as
>>>> +     * "fbarray_memseg-1048576k-0-0_PID_HOSTNAME" and length of PID
>>>> +     * can be 7 digits maximumly.
>>>> +     */
>>>> +    int fbarray_sec_name_len = 32 + 7 + 1 + HOST_NAME_MAX + 1;
>>>
>>> What does 32 stand for? Maybe #define both 32 and 7 values?
>> Hi Anatoly,
>>
>> Thank you for your comments! If my understanding is correct, the prefix
>> "fbarray_memseg-1048576k-0-0_" is 28 digits and it could be larger if
>> using the size of hugepage or the number of NUMA nodes are larger
>> possibly. However, I think 32 digits is still enough.
>>
>>   > Maybe #define both 32 and 7 values?
>> Yes. I think it should be better to use #define if this values are
>> referred several times.
> 
> 
> We can truncate to RTE_FBARRAY_NAME_LEN in all cases.
> And iiuc, rte_fbarray_init will refuse any longer name anyway.
Could I confirm the issue? I've understood that it is failed to validate 
the name of fbarray in fully_validate() at 
"lib/librte_eal/common/eal_common_fbarray.c:697".

static int
fully_validate(const char *name, unsigned int elt_sz, unsigned int len)
{
         if (name == NULL || elt_sz == 0 || len == 0 || len > INT_MAX) {
                 rte_errno = EINVAL;
                 return -1;
         }

         if (strnlen(name, RTE_FBARRAY_NAME_LEN) == RTE_FBARRAY_NAME_LEN) {
                 rte_errno = ENAMETOOLONG;
                 return -1;
         }
         return 0;
}

I should overwrite the definition of RTE_FBARRAY_NAME_LEN as previous 
patch in this case, and it causes an ABI breakage, right? If so, I would 
like to make the change and give up to update stable release.

Thanks,
Yasufumi

> 
>