doc: fix some syntax errors in netlink mmap sample code

Cc: Patrick McHardy <kaber@trash.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/Documentation/networking/netlink_mmap.txt b/Documentation/networking/netlink_mmap.txt
index e6088baf109d..5cc600587778 100644
--- a/Documentation/networking/netlink_mmap.txt
+++ b/Documentation/networking/netlink_mmap.txt
@@ -274,9 +274,9 @@ This example assumes some ring parameters of the ring setup are available.
                         /* Get next frame header */
                         hdr = rx_ring + frame_offset;
 
-                        if (hdr->nm_status == NL_MMAP_STATUS_VALID)
+                        if (hdr->nm_status == NL_MMAP_STATUS_VALID) {
                                 /* Regular memory mapped frame */
-                                nlh = (void *hdr) + NL_MMAP_HDRLEN;
+                                nlh = (void *)hdr + NL_MMAP_HDRLEN;
                                 len = hdr->nm_len;
 
                                 /* Release empty message immediately. May happen