[for-next][PATCH 7/7] ftrace: Use guard to take ftrace_lock in ftrace_graph_set_hash()

From: Steven Rostedt
Date: Wed Oct 30 2024 - 01:37:10 EST


From: Steven Rostedt <rostedt@xxxxxxxxxxx>

The ftrace_lock is taken for most of the ftrace_graph_set_hash() function
throughout the end. Use guard to take the ftrace_lock to simplify the exit
paths.

Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/20241028071308.406073025@xxxxxxxxxxx
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
kernel/trace/ftrace.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c0fabd7da5b2..b4ef469f4fd2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6816,12 +6816,10 @@ ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)

func_g.len = strlen(func_g.search);

- mutex_lock(&ftrace_lock);
+ guard(mutex)(&ftrace_lock);

- if (unlikely(ftrace_disabled)) {
- mutex_unlock(&ftrace_lock);
+ if (unlikely(ftrace_disabled))
return -ENODEV;
- }

do_for_each_ftrace_rec(pg, rec) {

@@ -6837,7 +6835,7 @@ ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
if (entry)
continue;
if (add_hash_entry(hash, rec->ip) == NULL)
- goto out;
+ return 0;
} else {
if (entry) {
free_hash_entry(hash, entry);
@@ -6846,13 +6844,8 @@ ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
}
}
} while_for_each_ftrace_rec();
-out:
- mutex_unlock(&ftrace_lock);

- if (fail)
- return -EINVAL;
-
- return 0;
+ return fail ? -EINVAL : 0;
}

static ssize_t
--
2.45.2