Re: [RFC][PATCH 05/18 v2] ftrace: Do not display non safe RCUfunctions in available_filter_functions

From: Steven Rostedt
Date: Sat Aug 31 2013 - 16:35:18 EST


On Sat, 2013-08-31 at 12:46 -0700, Paul E. McKenney wrote:

> > void arch_ftrace_update_code(int command);
> > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> > index 06504b2..be87ac9 100644
> > --- a/kernel/trace/ftrace.c
> > +++ b/kernel/trace/ftrace.c
> > @@ -2645,7 +2645,10 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
> > !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
> >
> > ((iter->flags & FTRACE_ITER_ENABLED) &&
> > - !(rec->flags & FTRACE_FL_ENABLED))) {
> > + !(rec->flags & FTRACE_FL_ENABLED)) ||
> > +
>
> OK, I'll bite... Why the blank line?

For readability. Here's the full if statement:

if (((iter->flags & FTRACE_ITER_FILTER) &&
!(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||

((iter->flags & FTRACE_ITER_NOTRACE) &&
!ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||

((iter->flags & FTRACE_ITER_ENABLED) &&
!(rec->flags & FTRACE_FL_ENABLED)) ||

((iter->flags & FTRACE_ITER_UNSAFE_ONLY) &&
!ftrace_lookup_ip(ftrace_unsafe_rcu, rec->ip)) ||

((iter->flags & FTRACE_ITER_NO_UNSAFE) &&
ftrace_lookup_ip(ftrace_unsafe_rcu, rec->ip))) {


They are grouped in pairs.

-- Steve

>
> Thanx, Paul
>
> > + ((iter->flags & FTRACE_ITER_NO_UNSAFE) &&
> > + ftrace_lookup_ip(ftrace_unsafe_rcu, rec->ip))) {
> >
> > rec = NULL;
> > goto retry;
> > @@ -2773,6 +2776,7 @@ ftrace_avail_open(struct inode *inode, struct file *file)
> > iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
> > if (iter) {
> > iter->pg = ftrace_pages_start;
> > + iter->flags = FTRACE_ITER_NO_UNSAFE;
> > iter->ops = &global_ops;
> > }
> >
> > --
> > 1.7.10.4
> >
> >


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