common/mlx5: fix Netlink receive message buffer size

If there are many VFs the Netlink message length sent by kernel
in reply to RTM_GETLINK request can be large. We should query
the size of message being received in advance and allocate
the large enough buffer to handle these large messages.

Fixes: ccdcba53a3f4 ("net/mlx5: use Netlink to add/remove MAC addresses")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

diff --git a/drivers/common/mlx5/linux/mlx5_nl.c b/drivers/common/mlx5/linux/mlx5_nl.c
index 3f1912d..dc8dafd 100644 (file)
--- a/drivers/common/mlx5/linux/mlx5_nl.c
+++ b/drivers/common/mlx5/linux/mlx5_nl.c
@@ -189,8 +189,8 @@ int
 mlx5_nl_init(int protocol)
 {
        int fd;
-       int sndbuf_size = MLX5_SEND_BUF_SIZE;
-       int rcvbuf_size = MLX5_RECV_BUF_SIZE;
+       int buf_size;
+       socklen_t opt_size;
        struct sockaddr_nl local = {
                .nl_family = AF_NETLINK,
        };
@@ -201,16 +201,36 @@ mlx5_nl_init(int protocol)
                rte_errno = errno;
                return -rte_errno;
        }
-       ret = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf_size, sizeof(int));
+       opt_size = sizeof(buf_size);
+       ret = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &buf_size, &opt_size);
        if (ret == -1) {
                rte_errno = errno;
                goto error;
        }
-       ret = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf_size, sizeof(int));
+       DRV_LOG(DEBUG, "Netlink socket send buffer: %d", buf_size);
+       if (buf_size < MLX5_SEND_BUF_SIZE) {
+               ret = setsockopt(fd, SOL_SOCKET, SO_SNDBUF,
+                                &buf_size, sizeof(buf_size));
+               if (ret == -1) {
+                       rte_errno = errno;
+                       goto error;
+               }
+       }
+       opt_size = sizeof(buf_size);
+       ret = getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &buf_size, &opt_size);
        if (ret == -1) {
                rte_errno = errno;
                goto error;
        }
+       DRV_LOG(DEBUG, "Netlink socket recv buffer: %d", buf_size);
+       if (buf_size < MLX5_RECV_BUF_SIZE) {
+               ret = setsockopt(fd, SOL_SOCKET, SO_RCVBUF,
+                                &buf_size, sizeof(buf_size));
+               if (ret == -1) {
+                       rte_errno = errno;
+                       goto error;
+               }
+       }
        ret = bind(fd, (struct sockaddr *)&local, sizeof(local));
        if (ret == -1) {
                rte_errno = errno;
@@ -332,11 +352,7 @@ mlx5_nl_recv(int nlsk_fd, uint32_t sn, int (*cb)(struct nlmsghdr *, void *arg),
             void *arg)
 {
        struct sockaddr_nl sa;
-       void *buf = mlx5_malloc(0, MLX5_RECV_BUF_SIZE, 0, SOCKET_ID_ANY);
-       struct iovec iov = {
-               .iov_base = buf,
-               .iov_len = MLX5_RECV_BUF_SIZE,
-       };
+       struct iovec iov;
        struct msghdr msg = {
                .msg_name = &sa,
                .msg_namelen = sizeof(sa),
@@ -344,18 +360,43 @@ mlx5_nl_recv(int nlsk_fd, uint32_t sn, int (*cb)(struct nlmsghdr *, void *arg),
                /* One message at a time */
                .msg_iovlen = 1,
        };
+       void *buf = NULL;
        int multipart = 0;
        int ret = 0;
 
-       if (!buf) {
-               rte_errno = ENOMEM;
-               return -rte_errno;
-       }
        do {
                struct nlmsghdr *nh;
-               int recv_bytes = 0;
+               int recv_bytes;
 
                do {
+                       /* Query length of incoming message. */
+                       iov.iov_base = NULL;
+                       iov.iov_len = 0;
+                       recv_bytes = recvmsg(nlsk_fd, &msg,
+                                            MSG_PEEK | MSG_TRUNC);
+                       if (recv_bytes < 0) {
+                               rte_errno = errno;
+                               ret = -rte_errno;
+                               goto exit;
+                       }
+                       if (recv_bytes == 0) {
+                               rte_errno = ENODATA;
+                               ret = -rte_errno;
+                               goto exit;
+                       }
+                       /* Allocate buffer to fetch the message. */
+                       if (recv_bytes < MLX5_RECV_BUF_SIZE)
+                               recv_bytes = MLX5_RECV_BUF_SIZE;
+                       mlx5_free(buf);
+                       buf = mlx5_malloc(0, recv_bytes, 0, SOCKET_ID_ANY);
+                       if (!buf) {
+                               rte_errno = ENOMEM;
+                               ret = -rte_errno;
+                               goto exit;
+                       }
+                       /* Fetch the message. */
+                       iov.iov_base = buf;
+                       iov.iov_len = recv_bytes;
                        recv_bytes = recvmsg(nlsk_fd, &msg, 0);
                        if (recv_bytes == -1) {
                                rte_errno = errno;