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

[Jiri Olsa]

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 <jo...@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