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 <viacheslavo@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5_flow_tcf.c b/drivers/net/mlx5/mlx5_flow_tcf.c
index 5a38940..4d154b6 100644 (file)
--- a/drivers/net/mlx5/mlx5_flow_tcf.c
+++ b/drivers/net/mlx5/mlx5_flow_tcf.c
@@ -3732,44 +3732,60 @@ flow_tcf_nl_ack(struct mlx5_flow_tcf_context *tcf,
 {
        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) {
+               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;