* Steven Rostedt (rost...@goodmis.org) wrote:
> On Sat, 4 May 2024 13:35:26 +0000
> "Dr. David Alan Gilbert" <d...@treblig.org> wrote:
>
> > Hi,
> > I've just posted a patch 'ftrace: Remove unused list
> > 'ftrace_direct_funcs''
> > that clears out some old code, but while at it I noticed the global
> > 'ftrace_direct_func_count'.
> >
> > As far as I can tell, it's never assigned (or initialised) but it is tested:
> >
> > kernel/trace/fgraph.c:
> > #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
> >
> > So I wasn't sure whether it was just safe to nuke that section
> > or whether it really needed fixing?
>
> Yes, after commit 8788ca164eb4bad ("ftrace: Remove the legacy
> _ftrace_direct API") that variable is no longer used.
OK, thanks, I'll send a follow up patch to my other patch to nuke
this as well.
Dave
> -- Steve
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