[PATCH 4/5] ftrace: Make ftrace_hash_rec_enable return update bool

Jiri Olsa
2016-03-16T14:35:01Z

Change __ftrace_hash_rec_update to return true in case
we need to update dynamic ftrace call records. It return
false in case no update is needed.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/trace/ftrace.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index eca592f977b2..3a9a12215b50 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1610,7 +1610,7 @@ static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
return keep_regs;
}

-static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
+static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
int filter_hash,
bool inc)
{
@@ -1618,12 +1618,13 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
struct ftrace_hash *other_hash;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
+ bool update = false;
int count = 0;
int all = 0;

/* Only update if the ops has been registered */
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
- return;
+ return false;

/*
* In the filter_hash case:
@@ -1650,7 +1651,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
* then there's nothing to do.
*/
if (ftrace_hash_empty(hash))
- return;
+ return false;
}

do_for_each_ftrace_rec(pg, rec) {
@@ -1694,7 +1695,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
if (inc) {
rec->flags++;
if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
- return;
+ return false;

/*
* If there's only a single callback registered to a
@@ -1720,7 +1721,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
rec->flags |= FTRACE_FL_REGS;
} else {
if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
- return;
+ return false;
rec->flags--;

/*
@@ -1753,22 +1754,28 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
*/
}
count++;
+
+ /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
+ update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
+
/* Shortcut, if we handled all records, we are done. */
if (!all && count == hash->count)
- return;
+ return update;
} while_for_each_ftrace_rec();
+
+ return update;
}

-static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
+static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
int filter_hash)
{
- __ftrace_hash_rec_update(ops, filter_hash, 0);
+ return __ftrace_hash_rec_update(ops, filter_hash, 0);
}

-static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
+static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
int filter_hash)
{
- __ftrace_hash_rec_update(ops, filter_hash, 1);
+ return __ftrace_hash_rec_update(ops, filter_hash, 1);
}

static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
--
2.4.3