latency_top: Remove the ULONG_MAX stack trace hackery

No architecture terminates the stack trace with ULONG_MAX anymore. The
consumer terminates on the first zero entry or at the number of entries, so
no functional change.

Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Potapenko <glider@google.com>
Link: https://lkml.kernel.org/r/20190410103644.853527514@linutronix.de

2 files changed, 7 insertions, 8 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6a803a0b75df..5569f215fc54 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -489,10 +489,9 @@ static int lstats_show_proc(struct seq_file *m, void *v)
                                    lr->count, lr->time, lr->max);
                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
                                 unsigned long bt = lr->backtrace[q];
+
                                 if (!bt)
                                         break;
-                                if (bt == ULONG_MAX)
-                                        break;
                                 seq_printf(m, " %ps", (void *)bt);
                         }
                         seq_putc(m, '\n');
diff --git a/kernel/latencytop.c b/kernel/latencytop.c
index 96b4179cee6a..f5a90ab3c6b9 100644
--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -120,8 +120,8 @@ account_global_scheduler_latency(struct task_struct *tsk,
                                 break;
                         }
 
-                        /* 0 and ULONG_MAX entries mean end of backtrace: */
-                        if (record == 0 || record == ULONG_MAX)
+                        /* 0 entry marks end of backtrace: */
+                        if (!record)
                                 break;
                 }
                 if (same) {
@@ -210,8 +210,8 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
                                 break;
                         }
 
-                        /* 0 and ULONG_MAX entries mean end of backtrace: */
-                        if (record == 0 || record == ULONG_MAX)
+                        /* 0 entry is end of backtrace */
+                        if (!record)
                                 break;
                 }
                 if (same) {
@@ -252,10 +252,10 @@ static int lstats_show(struct seq_file *m, void *v)
                                    lr->count, lr->time, lr->max);
                         for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
                                 unsigned long bt = lr->backtrace[q];
+
                                 if (!bt)
                                         break;
-                                if (bt == ULONG_MAX)
-                                        break;
+
                                 seq_printf(m, " %ps", (void *)bt);
                         }
                         seq_puts(m, "\n");