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tracing/kprobes: Simplify the logic of enable_trace_kprobe() 

The function enable_trace_kprobe() performs slightly differently if the file
parameter is passed in as NULL on non-NULL. Instead of checking file twice,
move the code between the two tests into a static inline helper function to
make the code easier to follow.

Link: http://lkml.kernel.org/r/20180725224728.7b1d5db2@vmware.local.home
Link: http://lkml.kernel.org/r/20180726121152.4dd54330@gandalf.local.home

Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (VMware) 2018-07-26 12:07:32 -04:00
parent 72809cbf67
commit 87107a25a2
1 changed files with 24 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
kernel/trace/trace_kprobe.c
View File

@ -393,6 +393,20 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
return NULL;
}
static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
{
int ret = 0;
if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
if (trace_kprobe_is_return(tk))
ret = enable_kretprobe(&tk->rp);
else
ret = enable_kprobe(&tk->rp.kp);
}
return ret;
}
/*
* Enable trace_probe
* if the file is NULL, enable "perf" handler, or enable "trace" handler.
@ -400,7 +414,7 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
static int
enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
{
struct event_file_link *link = NULL;
struct event_file_link *link;
int ret = 0;
if (file) {
@ -414,26 +428,18 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
list_add_tail_rcu(&link->list, &tk->tp.files);
tk->tp.flags |= TP_FLAG_TRACE;
} else
tk->tp.flags |= TP_FLAG_PROFILE;
if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
if (trace_kprobe_is_return(tk))
ret = enable_kretprobe(&tk->rp);
else
ret = enable_kprobe(&tk->rp.kp);
}
if (ret) {
if (file) {
/* Notice the if is true on not WARN() */
if (!WARN_ON_ONCE(!link))
list_del_rcu(&link->list);
ret = __enable_trace_kprobe(tk);
if (ret) {
list_del_rcu(&link->list);
kfree(link);
tk->tp.flags &= ~TP_FLAG_TRACE;
} else {
tk->tp.flags &= ~TP_FLAG_PROFILE;
}
} else {
tk->tp.flags |= TP_FLAG_PROFILE;
ret = __enable_trace_kprobe(tk);
if (ret)
tk->tp.flags &= ~TP_FLAG_PROFILE;
}
out:
return ret;