Re: [dpdk-dev] FW: [PATCH v2] Fixes: 57f90f894588("net/virtio: reuse packed ring functions")

[chupenghong <javin158@163.com>]

OK !









At 2020-08-13 15:23:01, "Vipul Ashri" <vipul.ashri@oracle.com> wrote:
>Hi Javin
>
>FYI
>http://patches.dpdk.org/patch/75476/
>The mentioned fix you are trying to submit is already addressed and in review with Xia chenbo since 10th august.
>Hope you can discard your patch as I have already sent the patch to dpdk community.
>
>Regards
>Vipul
>
>-----Original Message-----
>From: Xia, Chenbo [mailto:chenbo.xia@intel.com] 
>Sent: Wednesday, 12 August, 2020 17:31
>To: Vipul Ashri <vipul.ashri@oracle.com>; dev@dpdk.org
>Cc: Edwin Leung <edwin.leung@oracle.com>
>Subject: RE: [PATCH v2] Fixes: 57f90f894588("net/virtio: reuse packed ring functions")
>
>Hi Vipul,
>
>> -----Original Message-----
>> From: Vipul Ashri <vipul.ashri@oracle.com>
>> Sent: Wednesday, August 12, 2020 5:23 PM
>> To: dev@dpdk.org
>> Cc: Xia, Chenbo <chenbo.xia@intel.com>; vipul.ashri@oracle.com; 
>> edwin.leung@oracle.com
>> Subject: [PATCH v2] Fixes: 57f90f894588("net/virtio: reuse packed ring
>> functions")
>> 
>> Problem - Standard Tx packets are not going out and found broken  due 
>> to cleanup malfunctioning whereever below mentioned macro is  used.
>> 
>> RootCause - Here inside Macro 'ASSIGN_UNLESS_EQUAL(var, val)'
>>  assignment to 'var' argument passed is always failing as assignment  
>> done using 'var_' having local scope only.
>> 
>> Signed-off-by: Vipul Ashri <vipul.ashri@oracle.com>
>
>I understand now. Your patch makes sense. But your commit title/msg is still wrong. An example commit message should be (you could use this):
>
>net/virtio: fix wrong variable assignment in helper macro
>
>Inside Macro ASSIGN_UNLESS_EQUAL(var, val), assignment to var is always failing as assignment done using var_ having local scope only. This leads to TX packets not going out and found broken due to cleanup malfunctioning. This patch fixes the wrong variable assignment.
>
>Fixes: 57f90f894588("net/virtio: reuse packed ring functions")
>Cc: stable@dpdk.org
>
>Signed-off-by: Vipul Ashri <vipul.ashri@oracle.com>
>
>> ---
>>  drivers/net/virtio/virtqueue.h | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/net/virtio/virtqueue.h 
>> b/drivers/net/virtio/virtqueue.h index 105a9c00c..20c95471e 100644
>> --- a/drivers/net/virtio/virtqueue.h
>> +++ b/drivers/net/virtio/virtqueue.h
>> @@ -607,10 +607,8 @@ virtqueue_notify(struct virtqueue *vq)
>> 
>>  /* avoid write operation when necessary, to lessen cache issues */
>>  #define ASSIGN_UNLESS_EQUAL(var, val) do {	\
>> -	typeof(var) var_ = (var);		\
>> -	typeof(val) val_ = (val);		\
>> -	if ((var_) != (val_))			\
>> -		(var_) = (val_);		\
>> +	if ((var) != (val))			\
>> +		(var) = (val);			\
>>  } while (0)
>> 
>>  #define virtqueue_clear_net_hdr(hdr) do {		\
>> --
>> 2.28.0.windows.1