Re: [dpdk-dev] [PATCH v2 4/7] net/mlx5: e-switch VXLAN netlink routines update

[Yongseok Koh <yskoh@mellanox.com>]

On Mon, Oct 15, 2018 at 02:13:32PM +0000, Viacheslav Ovsiienko wrote:
> This part of patchset updates Netlink exchange routine. Message
> sequence numbers became not random ones, the multipart reply messages
> are supported, not propagating errors to the following socket calls,
> Netlink replies buffer size is increased to MNL_SOCKET_BUFFER_SIZE
> and now is preallocated at context creation time instead of stack
> usage. This update is needed to support Netlink query operations.
> 
> Suggested-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
Acked-by: Yongseok Koh <yskoh@mellanox.com>

Thanks

>  drivers/net/mlx5/mlx5_flow_tcf.c | 82 +++++++++++++++++++++++++++++-----------
>  1 file changed, 60 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow_tcf.c b/drivers/net/mlx5/mlx5_flow_tcf.c
> index 660d45e..d6840d5 100644
> --- a/drivers/net/mlx5/mlx5_flow_tcf.c
> +++ b/drivers/net/mlx5/mlx5_flow_tcf.c
> @@ -3372,37 +3372,75 @@ struct pedit_parser {
>  /**
>   * Send Netlink message with acknowledgment.
>   *
> - * @param ctx
> + * @param tcf
>   *   Flow context to use.
>   * @param nlh
>   *   Message to send. This function always raises the NLM_F_ACK flag before
>   *   sending.
> + * @param[in] msglen
> + *   Message length. Message buffer may contain multiple commands and
> + *   nlmsg_len field not always corresponds to actual message length.
> + *   If 0 specified the nlmsg_len field in header is used as message length.
> + * @param[in] cb
> + *   Callback handler for received message.
> + * @param[in] arg
> + *   Context pointer for callback handler.
>   *
>   * @return
>   *   0 on success, a negative errno value otherwise and rte_errno is set.
>   */
>  static int
> -flow_tcf_nl_ack(struct mlx5_flow_tcf_context *ctx, struct nlmsghdr *nlh)
> +flow_tcf_nl_ack(struct mlx5_flow_tcf_context *tcf,
> +		struct nlmsghdr *nlh,
> +		uint32_t msglen,
> +		mnl_cb_t cb, void *arg)
>  {
> -	alignas(struct nlmsghdr)
> -	uint8_t ans[mnl_nlmsg_size(sizeof(struct nlmsgerr)) +
> -		    nlh->nlmsg_len - sizeof(*nlh)];
> -	uint32_t seq = ctx->seq++;
> -	struct mnl_socket *nl = ctx->nl;
> -	int ret;
> -
> -	nlh->nlmsg_flags |= NLM_F_ACK;
> +	unsigned int portid = mnl_socket_get_portid(tcf->nl);
> +	uint32_t seq = tcf->seq++;
> +	int err, ret;
> +
> +	assert(tcf->nl);
> +	assert(tcf->buf);
> +	if (!seq)
> +		seq = tcf->seq++;
>  	nlh->nlmsg_seq = seq;
> -	ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
> -	if (ret != -1)
> -		ret = mnl_socket_recvfrom(nl, ans, sizeof(ans));
> -	if (ret != -1)
> -		ret = mnl_cb_run
> -			(ans, ret, seq, mnl_socket_get_portid(nl), NULL, NULL);
> +	if (!msglen) {
> +		msglen = nlh->nlmsg_len;
> +		nlh->nlmsg_flags |= NLM_F_ACK;
> +	}
> +	ret = mnl_socket_sendto(tcf->nl, nlh, msglen);
> +	err = (ret <= 0) ? errno : 0;
> +	nlh = (struct nlmsghdr *)(tcf->buf);
> +	/*
> +	 * The following loop postpones non-fatal errors until multipart
> +	 * messages are complete.
> +	 */
>  	if (ret > 0)
> +		while (true) {
> +			ret = mnl_socket_recvfrom(tcf->nl, tcf->buf,
> +						  tcf->buf_size);
> +			if (ret < 0) {
> +				err = errno;
> +				if (err != ENOSPC)
> +					break;
> +			}
> +			if (!err) {
> +				ret = mnl_cb_run(nlh, ret, seq, portid,
> +						 cb, arg);
> +				if (ret < 0) {
> +					err = errno;
> +					break;
> +				}
> +			}
> +			/* Will receive till end of multipart message */
> +			if (!(nlh->nlmsg_flags & NLM_F_MULTI) ||
> +			      nlh->nlmsg_type == NLMSG_DONE)
> +				break;
> +		}
> +	if (!err)
>  		return 0;
> -	rte_errno = errno;
> -	return -rte_errno;
> +	rte_errno = err;
> +	return -err;
>  }
>  
>  /**
> @@ -3433,7 +3471,7 @@ struct pedit_parser {
>  	nlh = dev_flow->tcf.nlh;
>  	nlh->nlmsg_type = RTM_NEWTFILTER;
>  	nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL;
> -	if (!flow_tcf_nl_ack(nl, nlh))
> +	if (!flow_tcf_nl_ack(nl, nlh, 0, NULL, NULL))
>  		return 0;
>  	return rte_flow_error_set(error, rte_errno,
>  				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
> @@ -3466,7 +3504,7 @@ struct pedit_parser {
>  	nlh = dev_flow->tcf.nlh;
>  	nlh->nlmsg_type = RTM_DELTFILTER;
>  	nlh->nlmsg_flags = NLM_F_REQUEST;
> -	flow_tcf_nl_ack(nl, nlh);
> +	flow_tcf_nl_ack(nl, nlh, 0, NULL, NULL);
>  }
>  
>  /**
> @@ -3842,7 +3880,7 @@ struct pedit_parser {
>  	tcm->tcm_handle = TC_H_MAKE(TC_H_INGRESS, 0);
>  	tcm->tcm_parent = TC_H_INGRESS;
>  	/* Ignore errors when qdisc is already absent. */
> -	if (flow_tcf_nl_ack(nl, nlh) &&
> +	if (flow_tcf_nl_ack(nl, nlh, 0, NULL, NULL) &&
>  	    rte_errno != EINVAL && rte_errno != ENOENT)
>  		return rte_flow_error_set(error, rte_errno,
>  					  RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
> @@ -3858,7 +3896,7 @@ struct pedit_parser {
>  	tcm->tcm_handle = TC_H_MAKE(TC_H_INGRESS, 0);
>  	tcm->tcm_parent = TC_H_INGRESS;
>  	mnl_attr_put_strz_check(nlh, sizeof(buf), TCA_KIND, "ingress");
> -	if (flow_tcf_nl_ack(nl, nlh))
> +	if (flow_tcf_nl_ack(nl, nlh, 0, NULL, NULL))
>  		return rte_flow_error_set(error, rte_errno,
>  					  RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
>  					  "netlink: failed to create ingress"
> -- 
> 1.8.3.1
>