Re: [PATCH v1 iproute2-next 1/4] rdma: add helper rd_sendrecv_msg()

[Steve Wise <swise@opengridcomputing.com>]

On 2/23/2019 3:31 AM, Leon Romanovsky wrote:
> On Sat, Feb 23, 2019 at 11:26:15AM +0200, Leon Romanovsky wrote:
>> On Thu, Feb 21, 2019 at 08:19:03AM -0800, Steve Wise wrote:
>>> This function sends the constructed netlink message and then
>>> receives the response, displaying any error text.
>>>
>>> Change 'rdma dev set' to use it.
>>>
>>> Signed-off-by: Steve Wise <swise@opengridcomputing.com>
>>> ---
>>>  rdma/dev.c   |  2 +-
>>>  rdma/rdma.h  |  1 +
>>>  rdma/utils.c | 21 +++++++++++++++++++++
>>>  3 files changed, 23 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/rdma/dev.c b/rdma/dev.c
>>> index 60ff4b31e320..d2949c378f08 100644
>>> --- a/rdma/dev.c
>>> +++ b/rdma/dev.c
>>> @@ -273,7 +273,7 @@ static int dev_set_name(struct rd *rd)
>>>  	mnl_attr_put_u32(rd->nlh, RDMA_NLDEV_ATTR_DEV_INDEX, rd->dev_idx);
>>>  	mnl_attr_put_strz(rd->nlh, RDMA_NLDEV_ATTR_DEV_NAME, rd_argv(rd));
>>>
>>> -	return rd_send_msg(rd);
>>> +	return rd_sendrecv_msg(rd, seq);
>>>  }
>>>
>>>  static int dev_one_set(struct rd *rd)
>>> diff --git a/rdma/rdma.h b/rdma/rdma.h
>>> index 547bb5749a39..20be2f12c4f8 100644
>>> --- a/rdma/rdma.h
>>> +++ b/rdma/rdma.h
>>> @@ -115,6 +115,7 @@ bool rd_check_is_key_exist(struct rd *rd, const char *key);
>>>   */
>>>  int rd_send_msg(struct rd *rd);
>>>  int rd_recv_msg(struct rd *rd, mnl_cb_t callback, void *data, uint32_t seq);
>>> +int rd_sendrecv_msg(struct rd *rd, unsigned int seq);
>>>  void rd_prepare_msg(struct rd *rd, uint32_t cmd, uint32_t *seq, uint16_t flags);
>>>  int rd_dev_init_cb(const struct nlmsghdr *nlh, void *data);
>>>  int rd_attr_cb(const struct nlattr *attr, void *data);
>>> diff --git a/rdma/utils.c b/rdma/utils.c
>>> index 069d44fece10..a6f2826c9605 100644
>>> --- a/rdma/utils.c
>>> +++ b/rdma/utils.c
>>> @@ -664,6 +664,27 @@ int rd_recv_msg(struct rd *rd, mnl_cb_t callback, void *data, unsigned int seq)
>>>  	return ret;
>>>  }
>>>
>>> +static int null_cb(const struct nlmsghdr *nlh, void *data)
>>> +{
>>> +	return MNL_CB_OK;
>>> +}
>>> +
>>> +int rd_sendrecv_msg(struct rd *rd, unsigned int seq)
>>> +{
>>> +	int ret;
>>> +
>>> +	ret = rd_send_msg(rd);
>>> +	if (ret) {
>>> +		perror(NULL);
>> This is more or less already done in rd_send_msg() and that function
>> prints something in case of execution error. So the missing piece
>> is to update rd_recv_msg(), so all places will "magically" print errors
>> and not only dev_set_name().
>>
>>> +		goto out;
>>> +	}
>>> +	ret = rd_recv_msg(rd, null_cb, rd, seq);
> Will this "null_cb" work for all send/recv flows or only in flows where
> response can be error only? 


Only those flows where no nl attributes are expected to be returned.


> Will we need this recv_msg if we implement
> extack support?


I'm not sure how extack works.  Do you know?

Thanks!

Steve.