[PATCH] ftrace: Remove unused global 'ftrace_direct_func_count'

From: linux
Date: Mon May 06 2024 - 19:33:38 EST


From: "Dr. David Alan Gilbert" <linux@xxxxxxxxxxx>

Commit 8788ca164eb4b ("ftrace: Remove the legacy _ftrace_direct API")
stopped setting the 'ftrace_direct_func_count' variable, but left
it around. Clean it up.

Signed-off-by: Dr. David Alan Gilbert <linux@xxxxxxxxxxx>
---
include/linux/ftrace.h | 2 --
kernel/trace/fgraph.c | 11 -----------
kernel/trace/ftrace.c | 1 -
3 files changed, 14 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index b01cca36147ff..e3a83ebd1b333 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -413,7 +413,6 @@ struct ftrace_func_entry {
};

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
-extern int ftrace_direct_func_count;
unsigned long ftrace_find_rec_direct(unsigned long ip);
int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
@@ -425,7 +424,6 @@ void ftrace_stub_direct_tramp(void);

#else
struct ftrace_ops;
-# define ftrace_direct_func_count 0
static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
{
return 0;
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index c83c005e654e3..a130b2d898f7c 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -125,17 +125,6 @@ int function_graph_enter(unsigned long ret, unsigned long func,
{
struct ftrace_graph_ent trace;

-#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
- /*
- * Skip graph tracing if the return location is served by direct trampoline,
- * since call sequence and return addresses are unpredictable anyway.
- * Ex: BPF trampoline may call original function and may skip frame
- * depending on type of BPF programs attached.
- */
- if (ftrace_direct_func_count &&
- ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
- return -EBUSY;
-#endif
trace.func = func;
trace.depth = ++current->curr_ret_depth;

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b18b4ece3d7c9..adf34167c3418 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2538,7 +2538,6 @@ ftrace_find_unique_ops(struct dyn_ftrace *rec)
/* Protected by rcu_tasks for reading, and direct_mutex for writing */
static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
static DEFINE_MUTEX(direct_mutex);
-int ftrace_direct_func_count;

/*
* Search the direct_functions hash to see if the given instruction pointer
--
2.45.0