Re: [dpdk-dev] [PATCH] kni: fix rte_kni_update_link

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/28/2019 1:49 PM, Igor Ryzhov wrote:
> Hi again,
> 
> Sorry for bothering, I should have done more testing. It works as it is now.
> So, self NACK on the patch.

Thanks for the update Igor.

Since the file is pseudo-file, sysfs, I would expect no seek operation should be
required, your update confirms this.
Meanwhile there is a unit test 'kni_autotest' when you want to test link update.

Thanks,
ferruh

> 
> Best regards,
> Igor
> 
> On Mon, Jan 28, 2019 at 2:45 PM Igor Ryzhov <iryzhov@nfware.com> wrote:
> 
>> Hi Ferruh,
>>
>> Can you, please, take a look at this patch?
>> The current implementation is broken, I think the patch should be merged
>> into 19.02 and 18.11.1.
>>
>> Best regards,
>> Igor
>>
>> On Thu, Jan 24, 2019 at 11:47 PM Igor Ryzhov <iryzhov@nfware.com> wrote:
>>
>>> After read, file offset must be set to 0 before write.
>>> Otherwise, the third byte will be overwritten instead of the first.
>>>
>>> Fixes: c6fd54f28c24 ("kni: add function to set link state on kernel
>>> interface")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
>>> ---
>>>  lib/librte_kni/rte_kni.c | 6 ++++++
>>>  1 file changed, 6 insertions(+)
>>>
>>> diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
>>> index 73aeccccf..5899bb14a 100644
>>> --- a/lib/librte_kni/rte_kni.c
>>> +++ b/lib/librte_kni/rte_kni.c
>>> @@ -746,6 +746,12 @@ rte_kni_update_link(struct rte_kni *kni, unsigned
>>> int linkup)
>>>         }
>>>         old_linkup = (old_carrier[0] == '1');
>>>
>>> +       if (lseek(fd, 0, SEEK_SET) == -1) {
>>> +               RTE_LOG(ERR, KNI, "Failed to change file position:
>>> %s.\n", path);
>>> +               close(fd);
>>> +               return -1;
>>> +       }
>>> +
>>>         new_carrier = linkup ? "1" : "0";
>>>         ret = write(fd, new_carrier, 1);
>>>         if (ret < 1) {
>>> --
>>> 2.20.1
>>>
>>>
>