[PATCH -mm 3/5] samples/bpf/tracex2: replace hard-coded 16 with TASK_COMM_LEN

[Yafang Shao <laoar.shao@gmail.com>]

The comm used in tracex2 should have the same size with the comm in
task_struct, we'd better define the size of it as TASK_COMM_LEN to make it
more grepable.

linux/sched.h can be included in tracex2 kernel code, but it can't be
included in tracex2 userspace code. So a new marco TASK_COMM_LEN is
defined in tracex2 userspace code.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
---
 samples/bpf/tracex2_kern.c | 3 ++-
 samples/bpf/tracex2_user.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/tracex2_kern.c b/samples/bpf/tracex2_kern.c
index 5bc696bac27d..51dbaf765cd5 100644
--- a/samples/bpf/tracex2_kern.c
+++ b/samples/bpf/tracex2_kern.c
@@ -7,6 +7,7 @@
 #include <linux/skbuff.h>
 #include <linux/netdevice.h>
 #include <linux/version.h>
+#include <linux/sched.h>
 #include <uapi/linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
@@ -65,7 +66,7 @@ static unsigned int log2l(unsigned long v)
 }
 
 struct hist_key {
-	char comm[16];
+	char comm[TASK_COMM_LEN];
 	u64 pid_tgid;
 	u64 uid_gid;
 	u64 index;
diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c
index 1626d51dfffd..b728a946d83d 100644
--- a/samples/bpf/tracex2_user.c
+++ b/samples/bpf/tracex2_user.c
@@ -12,6 +12,7 @@
 
 #define MAX_INDEX	64
 #define MAX_STARS	38
+#define TASK_COMM_LEN	16
 
 /* my_map, my_hist_map */
 static int map_fd[2];
@@ -28,7 +29,7 @@ static void stars(char *str, long val, long max, int width)
 }
 
 struct task {
-	char comm[16];
+	char comm[TASK_COMM_LEN];
 	__u64 pid_tgid;
 	__u64 uid_gid;
 };
-- 
2.17.1