[PATCH -tip 4/4] ftrace: Remove record freezing

[Masami Hiramatsu <mhiramat@redhat.com>]

Remove record freezing. Because kprobes never puts probe on
ftrace's mcount call anymore, it doesn't need ftrace to check
whether kprobes on it.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
---

 include/linux/ftrace.h |    1 -
 kernel/trace/ftrace.c  |   39 ---------------------------------------
 2 files changed, 0 insertions(+), 40 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 9d127ef..eb054ae 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -143,7 +143,6 @@ enum {
 	FTRACE_FL_ENABLED	= (1 << 3),
 	FTRACE_FL_NOTRACE	= (1 << 4),
 	FTRACE_FL_CONVERTED	= (1 << 5),
-	FTRACE_FL_FROZEN	= (1 << 6),
 };
 
 struct dyn_ftrace {
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3d90661..1904797 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -22,7 +22,6 @@
 #include <linux/hardirq.h>
 #include <linux/kthread.h>
 #include <linux/uaccess.h>
-#include <linux/kprobes.h>
 #include <linux/ftrace.h>
 #include <linux/sysctl.h>
 #include <linux/ctype.h>
@@ -898,36 +897,6 @@ static struct dyn_ftrace *ftrace_free_records;
 		}				\
 	}
 
-#ifdef CONFIG_KPROBES
-
-static int frozen_record_count;
-
-static inline void freeze_record(struct dyn_ftrace *rec)
-{
-	if (!(rec->flags & FTRACE_FL_FROZEN)) {
-		rec->flags |= FTRACE_FL_FROZEN;
-		frozen_record_count++;
-	}
-}
-
-static inline void unfreeze_record(struct dyn_ftrace *rec)
-{
-	if (rec->flags & FTRACE_FL_FROZEN) {
-		rec->flags &= ~FTRACE_FL_FROZEN;
-		frozen_record_count--;
-	}
-}
-
-static inline int record_frozen(struct dyn_ftrace *rec)
-{
-	return rec->flags & FTRACE_FL_FROZEN;
-}
-#else
-# define freeze_record(rec)			({ 0; })
-# define unfreeze_record(rec)			({ 0; })
-# define record_frozen(rec)			({ 0; })
-#endif /* CONFIG_KPROBES */
-
 static void ftrace_free_rec(struct dyn_ftrace *rec)
 {
 	rec->freelist = ftrace_free_records;
@@ -1091,14 +1060,6 @@ static void ftrace_replace_code(int enable)
 		    !(rec->flags & FTRACE_FL_CONVERTED))
 			continue;
 
-		/* ignore updates to this record's mcount site */
-		if (get_kprobe((void *)rec->ip)) {
-			freeze_record(rec);
-			continue;
-		} else {
-			unfreeze_record(rec);
-		}
-
 		failed = __ftrace_replace_code(rec, enable);
 		if (failed) {
 			rec->flags |= FTRACE_FL_FAILED;


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com