6.12-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt rostedt@goodmis.org
[ Upstream commit 2b36a97aeeb71b1e4a48bfedc7f21f44aeb1e6fb ]
There are a couple functions in trace_events_hist.c that have "goto out" or equivalent on error in order to release locks that were taken. This can be error prone or just simply make the code more complex.
Switch every location that ends with unlocking a mutex on error over to using the guard(mutex)() infrastructure to let the compiler worry about releasing locks. This makes the code easier to read and understand.
Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Link: https://lore.kernel.org/20241219201345.694601480@goodmis.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Stable-dep-of: 0b4ffbe4888a ("tracing: Correct the refcount if the hist/hist_debug file fails to open") Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace_events_hist.c | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 31f5ad322fab0..5d344bc690d99 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5597,25 +5597,19 @@ static int hist_show(struct seq_file *m, void *v) { struct event_trigger_data *data; struct trace_event_file *event_file; - int n = 0, ret = 0; + int n = 0;
- mutex_lock(&event_mutex); + guard(mutex)(&event_mutex);
event_file = event_file_file(m->private); - if (unlikely(!event_file)) { - ret = -ENODEV; - goto out_unlock; - } + if (unlikely(!event_file)) + return -ENODEV;
list_for_each_entry(data, &event_file->triggers, list) { if (data->cmd_ops->trigger_type == ETT_EVENT_HIST) hist_trigger_show(m, data, n++); } - - out_unlock: - mutex_unlock(&event_mutex); - - return ret; + return 0; }
static int event_hist_open(struct inode *inode, struct file *file) @@ -5876,25 +5870,19 @@ static int hist_debug_show(struct seq_file *m, void *v) { struct event_trigger_data *data; struct trace_event_file *event_file; - int n = 0, ret = 0; + int n = 0;
- mutex_lock(&event_mutex); + guard(mutex)(&event_mutex);
event_file = event_file_file(m->private); - if (unlikely(!event_file)) { - ret = -ENODEV; - goto out_unlock; - } + if (unlikely(!event_file)) + return -ENODEV;
list_for_each_entry(data, &event_file->triggers, list) { if (data->cmd_ops->trigger_type == ETT_EVENT_HIST) hist_trigger_debug_show(m, data, n++); } - - out_unlock: - mutex_unlock(&event_mutex); - - return ret; + return 0; }
static int event_hist_debug_open(struct inode *inode, struct file *file)