kprobe: Simplify prepare_kprobe() by dropping redundant version

The function prepare_kprobe() is called during kprobe registration and
is responsible for ensuring any architecture related preparation for
the kprobe is done before returning.

One of two versions of prepare_kprobe() is chosen depending on the
availability of KPROBE_ON_FTRACE in the kernel configuration.

Simplify the code by dropping the version when KPROBE_ON_FTRACE is not
selected - instead relying on kprobe_ftrace() to return false when
KPROBE_ON_FTRACE is not set.

No functional change.

Link: https://lkml.kernel.org/r/163163033696.489837.9264661820279300788.stgit@devnote2

Signed-off-by: Punit Agrawal <punitagrawal@gmail.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 26fc990..cfa9d3c2 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1033,15 +1033,6 @@ static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
 static int kprobe_ipmodify_enabled;
 static int kprobe_ftrace_enabled;
 
-/* Must ensure p->addr is really on ftrace */
-static int prepare_kprobe(struct kprobe *p)
-{
-	if (!kprobe_ftrace(p))
-		return arch_prepare_kprobe(p);
-
-	return arch_prepare_kprobe_ftrace(p);
-}
-
 /* Caller must lock kprobe_mutex */
 static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
 			       int *cnt)
@@ -1113,11 +1104,6 @@ static int disarm_kprobe_ftrace(struct kprobe *p)
 		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
 }
 #else	/* !CONFIG_KPROBES_ON_FTRACE */
-static inline int prepare_kprobe(struct kprobe *p)
-{
-	return arch_prepare_kprobe(p);
-}
-
 static inline int arm_kprobe_ftrace(struct kprobe *p)
 {
 	return -ENODEV;
@@ -1129,6 +1115,15 @@ static inline int disarm_kprobe_ftrace(struct kprobe *p)
 }
 #endif
 
+static int prepare_kprobe(struct kprobe *p)
+{
+	/* Must ensure p->addr is really on ftrace */
+	if (kprobe_ftrace(p))
+		return arch_prepare_kprobe_ftrace(p);
+
+	return arch_prepare_kprobe(p);
+}
+
 /* Arm a kprobe with text_mutex */
 static int arm_kprobe(struct kprobe *kp)
 {