From: Paul E. McKenney <paulmck@kernel.org>
Date: Thu, 24 Apr 2025 19:28:24 +0000 (-0700)
Subject: ratelimit: Use nolock_ret restructuring to collapse common case code
X-Git-Tag: v6.16-rc1~178^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b2cce999c8f5a03916b11b1e4ce192d223ab4f5;p=thirdparty%2Fkernel%2Flinux.git

ratelimit: Use nolock_ret restructuring to collapse common case code

Now that unlock_ret releases the lock, then falls into nolock_ret, which
handles ->missed based on the value of ret, the common-case lock-held
code can be collapsed into a single "if" statement with a single-statement
"then" clause.

Yes, we could go further and just assign the "if" condition to ret,
but in the immortal words of MSDOS, "Are you sure?".

Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
---

diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index bcda7c61fc6ff..dcc063af195eb 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -88,17 +88,10 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
 			}
 		}
 	}
-	if (burst) {
-		int n_left = atomic_read(&rs->rs_n_left);
 
-		/* The burst might have been taken by a parallel call. */
-
-		if (n_left > 0) {
-			n_left = atomic_dec_return(&rs->rs_n_left);
-			if (n_left >= 0)
-				ret = 1;
-		}
-	}
+	/* Note that the burst might be taken by a parallel call. */
+	if (burst && atomic_read(&rs->rs_n_left) > 0 && atomic_dec_return(&rs->rs_n_left) >= 0)
+		ret = 1;
 
 unlock_ret:
 	raw_spin_unlock_irqrestore(&rs->lock, flags);