ftrace: Factor out __ftrace_hash_move()

The __ftrace_hash_move() is to allocates properly-sized hash and move
entries in the src ftrace_hash.  It will be used to set function graph
filters which has nothing to do with the dyn_ftrace records.

Link: http://lkml.kernel.org/r/20170120024447.26097-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index eb230f0..37b0e94 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1383,9 +1383,8 @@ ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
                                       struct ftrace_hash *new_hash);
 
-static int
-ftrace_hash_move(struct ftrace_ops *ops, int enable,
-                struct ftrace_hash **dst, struct ftrace_hash *src)
+static struct ftrace_hash *
+__ftrace_hash_move(struct ftrace_hash *src)
 {
        struct ftrace_func_entry *entry;
        struct hlist_node *tn;
@@ -1393,21 +1392,13 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
        struct ftrace_hash *new_hash;
        int size = src->count;
        int bits = 0;
-       int ret;
        int i;
 
-       /* Reject setting notrace hash on IPMODIFY ftrace_ops */
-       if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
-               return -EINVAL;
-
        /*
-        * If the new source is empty, just free dst and assign it
-        * the empty_hash.
+        * If the new source is empty, just return the empty_hash.
         */
-       if (!src->count) {
-               new_hash = EMPTY_HASH;
-               goto update;
-       }
+       if (!src->count)
+               return EMPTY_HASH;
 
        /*
         * Make the hash size about 1/2 the # found
@@ -1421,7 +1412,7 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
 
        new_hash = alloc_ftrace_hash(bits);
        if (!new_hash)
-               return -ENOMEM;
+               return NULL;
 
        size = 1 << src->size_bits;
        for (i = 0; i < size; i++) {
@@ -1432,7 +1423,24 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
                }
        }
 
-update:
+       return new_hash;
+}
+
+static int
+ftrace_hash_move(struct ftrace_ops *ops, int enable,
+                struct ftrace_hash **dst, struct ftrace_hash *src)
+{
+       struct ftrace_hash *new_hash;
+       int ret;
+
+       /* Reject setting notrace hash on IPMODIFY ftrace_ops */
+       if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
+               return -EINVAL;
+
+       new_hash = __ftrace_hash_move(src);
+       if (!new_hash)
+               return -ENOMEM;
+
        /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
        if (enable) {
                /* IPMODIFY should be updated only when filter_hash updating */