[PATCH v2 1/3] blktrace: introduce 'blk_trace_{start,stop}' helper

Ye Bin
2022-10-18T14:29:50Z

Introduce 'blk_trace_{start,stop}' helper. No functional changed.

Signed-off-by: Ye Bin <yebin@huaweicloud.com>
---
kernel/trace/blktrace.c | 82 ++++++++++++++++++++++-------------------
1 file changed, 44 insertions(+), 38 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 7f5eb295fe19..f07a03c1e052 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -346,6 +346,45 @@ static void put_probe_ref(void)
mutex_unlock(&blk_probe_mutex);
}

+static int blk_trace_start(struct blk_trace *bt)
+{
+ /*
+ * For starting a trace, we can transition from a setup or stopped
+ * trace.
+ */
+ if (bt->trace_state == Blktrace_setup ||
+ bt->trace_state == Blktrace_stopped) {
+ blktrace_seq++;
+ smp_mb();
+ bt->trace_state = Blktrace_running;
+ raw_spin_lock_irq(&running_trace_lock);
+ list_add(&bt->running_list, &running_trace_list);
+ raw_spin_unlock_irq(&running_trace_lock);
+
+ trace_note_time(bt);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int blk_trace_stop(struct blk_trace *bt)
+{
+ /*
+ * For stopping a trace, the state must be running
+ */
+ if (bt->trace_state == Blktrace_running) {
+ bt->trace_state = Blktrace_stopped;
+ raw_spin_lock_irq(&running_trace_lock);
+ list_del_init(&bt->running_list);
+ raw_spin_unlock_irq(&running_trace_lock);
+ relay_flush(bt->rchan);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
{
synchronize_rcu();
@@ -658,7 +697,6 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,

static int __blk_trace_startstop(struct request_queue *q, int start)
{
- int ret;
struct blk_trace *bt;

bt = rcu_dereference_protected(q->blk_trace,
@@ -666,36 +704,10 @@ static int __blk_trace_startstop(struct request_queue *q, int start)
if (bt == NULL)
return -EINVAL;

- /*
- * For starting a trace, we can transition from a setup or stopped
- * trace. For stopping a trace, the state must be running
- */
- ret = -EINVAL;
- if (start) {
- if (bt->trace_state == Blktrace_setup ||
- bt->trace_state == Blktrace_stopped) {
- blktrace_seq++;
- smp_mb();
- bt->trace_state = Blktrace_running;
- raw_spin_lock_irq(&running_trace_lock);
- list_add(&bt->running_list, &running_trace_list);
- raw_spin_unlock_irq(&running_trace_lock);
-
- trace_note_time(bt);
- ret = 0;
- }
- } else {
- if (bt->trace_state == Blktrace_running) {
- bt->trace_state = Blktrace_stopped;
- raw_spin_lock_irq(&running_trace_lock);
- list_del_init(&bt->running_list);
- raw_spin_unlock_irq(&running_trace_lock);
- relay_flush(bt->rchan);
- ret = 0;
- }
- }
-
- return ret;
+ if (start)
+ return blk_trace_start(bt);
+ else
+ return blk_trace_stop(bt);
}

int blk_trace_startstop(struct request_queue *q, int start)
@@ -1614,13 +1626,7 @@ static int blk_trace_remove_queue(struct request_queue *q)
if (bt == NULL)
return -EINVAL;

- if (bt->trace_state == Blktrace_running) {
- bt->trace_state = Blktrace_stopped;
- raw_spin_lock_irq(&running_trace_lock);
- list_del_init(&bt->running_list);
- raw_spin_unlock_irq(&running_trace_lock);
- relay_flush(bt->rchan);
- }
+ blk_trace_stop(bt);

put_probe_ref();
synchronize_rcu();
--
2.31.1