From 87107a25a2f857693156f075da6e2a1438f4b4a0 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 26 Jul 2018 12:07:32 -0400 Subject: [PATCH] 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 Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_kprobe.c | 42 +++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 18 deletions(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 6b71860f3998..0534eb8b7640 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -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; -- 2.30.2