blktrace: introduce 'blk_trace_{start,stop}' helper

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

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019033602.752383-2-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 7f5eb295fe198997711d0653fdd0516b486e2bce..50b6f241b5f778b7ee39fca48d56ff065e8fcb33 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -346,6 +346,37 @@ static void put_probe_ref(void)
        mutex_unlock(&blk_probe_mutex);
 }
 
+static int blk_trace_start(struct blk_trace *bt)
+{
+       if (bt->trace_state != Blktrace_setup &&
+           bt->trace_state != Blktrace_stopped)
+               return -EINVAL;
+
+       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;
+}
+
+static int blk_trace_stop(struct blk_trace *bt)
+{
+       if (bt->trace_state != Blktrace_running)
+               return -EINVAL;
+
+       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;
+}
+
 static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
 {
        synchronize_rcu();
@@ -658,7 +689,6 @@ 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 +696,10 @@ 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 +1618,7 @@ 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();