Monday, November 12, 2018 10:02 PM, Slava Ovsiienko:
> Subject: [PATCH 2/4] net/mlx5: fix Netlink communication routine
>
> While receiving the Netlink reply messages we should stop at DONE or ACK
> message. The existing implementation stops at DONE message or if no
> multiple message flag set ( NLM_F_MULTI). It prevents the single query
> requests from working, these requests send the single reply message
> without multi-message flag followed by ACK message. This patch fixes
> receiving part of Netlink communication routine.
>
> Fixes: 6e74990b3463 ("net/mlx5: update E-Switch VXLAN netlink routines")
>
> Signed-off-by: Viacheslav Ovsiienko <viachesl...@mellanox.com>
> ---
> drivers/net/mlx5/mlx5_flow_tcf.c | 58 +++++++++++++++++++++++++-----
> ----------
> 1 file changed, 37 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/net/mlx5/mlx5_flow_tcf.c
> b/drivers/net/mlx5/mlx5_flow_tcf.c
> index 5a38940..4d154b6 100644
> --- a/drivers/net/mlx5/mlx5_flow_tcf.c
> +++ b/drivers/net/mlx5/mlx5_flow_tcf.c
> @@ -3732,44 +3732,60 @@ struct pedit_parser { {
> unsigned int portid = mnl_socket_get_portid(tcf->nl);
> uint32_t seq = tcf->seq++;
> - int err, ret;
> + int ret, err = 0;
>
> assert(tcf->nl);
> assert(tcf->buf);
> - if (!seq)
> + if (!seq) {
> /* seq 0 is reserved for kernel event-driven notifications. */
> seq = tcf->seq++;
> + }
> nlh->nlmsg_seq = seq;
> nlh->nlmsg_flags |= NLM_F_ACK;
> ret = mnl_socket_sendto(tcf->nl, nlh, nlh->nlmsg_len);
> - err = (ret <= 0) ? errno : 0;
> + if (ret <= 0) {
> + /* Message send error occurres. */
> + rte_errno = errno;
> + return -rte_errno;
> + }
> 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);
> + while (true) {
This while(true) is a bit disturbing (I know it exists also before).
Can't we bound it to some limit, e.g. is there any multiply of tcf->buf_size
that if we receive more than that it is for sure an error?
> + ret = mnl_socket_recvfrom(tcf->nl, tcf->buf, tcf->buf_size);
> + if (ret < 0) {
> + err = errno;
> + /*
> + * In case of overflow Will receive till
> + * end of multipart message. We may lost part
> + * of reply messages but mark and return an error.
> + */
> + if (err != ENOSPC ||
> + !(nlh->nlmsg_flags & NLM_F_MULTI) ||
> + nlh->nlmsg_type == NLMSG_DONE)
> + break;
> + } else {
> + ret = mnl_cb_run(nlh, ret, seq, portid, cb, arg);
> + if (!ret) {
> + /*
> + * libmnl returns 0 if DONE or
> + * success ACK message found.
> + */
> + break;
> + }
> if (ret < 0) {
> + /*
> + * ACK message with error found
> + * or some error occurred.
> + */
> 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;
> + }
> + /* We should continue receiving. */
> }
> + }
> if (!err)
> return 0;
> rte_errno = err;
> --
> 1.8.3.1
