[PATCH v5 17/21] ratelimit: Use nolock_ret label to collapse lock-failure code

[Paul E. McKenney]

Now that we have a nolock_ret label that handles ->missed correctly
based on the value of ret, we can eliminate a local variable and collapse
several "if" statements on the lock-acquisition-failure code path.

Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@xxxxxx/
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Cc: Mateusz Guzik <mjguzik@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: John Ogness <john.ogness@xxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
 lib/ratelimit.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index e7101a79c6973..bcda7c61fc6ff 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -58,20 +58,10 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
 	 * the current lock owner is just about to reset it.
 	 */
 	if (!raw_spin_trylock_irqsave(&rs->lock, flags)) {
-		unsigned int rs_flags = READ_ONCE(rs->flags);
-
-		if (rs_flags & RATELIMIT_INITIALIZED && burst) {
-			int n_left = atomic_read(&rs->rs_n_left);
-
-			if (n_left <= 0)
-				return 0;
-			n_left = atomic_dec_return(&rs->rs_n_left);
-			if (n_left >= 0)
-				return 1;
-		}
-
-		ratelimit_state_inc_miss(rs);
-		return 0;
+		if (READ_ONCE(rs->flags) & RATELIMIT_INITIALIZED && burst &&
+		    atomic_read(&rs->rs_n_left) > 0 && atomic_dec_return(&rs->rs_n_left) >= 0)
+			ret = 1;
+		goto nolock_ret;
 	}
 
 	if (!(rs->flags & RATELIMIT_INITIALIZED)) {
-- 
2.40.1