samples/bpf: xdp_monitor increase memory rlimit

Other concurrent running programs, like perf or the XDP program what
needed to be monitored, might take up part of the max locked memory
limit.  Thus, the xdp_monitor tool have to set the RLIMIT_MEMLOCK to
RLIM_INFINITY, as it cannot determine a more sane limit.

Using the man exit(3) specified EXIT_FAILURE return exit code, and
correct other users too.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

samples/bpf/xdp_monitor_user.c

@@ -20,6 +20,7 @@ static const char *__doc_err_only__=
 #include <unistd.h>
 #include <locale.h>
 
+#include <sys/resource.h>
 #include <getopt.h>
 #include <net/if.h>
 #include <time.h>
@@ -295,6 +296,7 @@ static void print_bpf_prog_info(void)
 
 int main(int argc, char **argv)
 {
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	int longindex = 0, opt;
 	int ret = EXIT_SUCCESS;
 	char bpf_obj_file[256];
@@ -325,13 +327,18 @@ int main(int argc, char **argv)
 		}
 	}
 
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return EXIT_FAILURE;
+	}
+
 	if (load_bpf_file(bpf_obj_file)) {
 		printf("ERROR - bpf_log_buf: %s", bpf_log_buf);
-		return 1;
+		return EXIT_FAILURE;
 	}
 	if (!prog_fd[0]) {
 		printf("ERROR - load_bpf_file: %s\n", strerror(errno));
-		return 1;
+		return EXIT_FAILURE;
 	}
 
 	if (debug) {