Re: [PATCH] ftrace: Remove unused global 'ftrace_direct_func_count'

From: Dr. David Alan Gilbert
Date: Mon May 06 2024 - 19:36:05 EST


* linux@xxxxxxxxxxx (linux@xxxxxxxxxxx) wrote:
> 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>

FYI this is on top of my earlier 'ftrace: Remove unused list 'ftrace_direct_funcs'

Dave

> ---
> 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
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/