linux-kernel - [PATCH v4 22/40] tty: nozomi: optimize interrupt

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Date: Thu, 20 Jun 2024 10:56:45 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	linux-serial@...r.kernel.org
Cc: Yury Norov <yury.norov@...il.com>,
	Alexey Klimov <alexey.klimov@...aro.org>,
	Bart Van Assche <bvanassche@....org>,
	Jan Kara <jack@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Wilcox <willy@...radead.org>,
	Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Sergey Shtylyov <s.shtylyov@....ru>
Subject: [PATCH v4 22/40] tty: nozomi: optimize interrupt_handler()

In the exit path of interrupt_handler(), dc->flip map is traversed bit
by bit to find and clear set bits and call tty_flip_buffer_push() for
corresponding ports.

Simplify it by using for_each_test_and_clear_bit(), as it skips already
clear bits.

Signed-off-by: Yury Norov <yury.norov@...il.com>
---
 drivers/tty/nozomi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index e28a921c1637..2fe063190867 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -28,6 +28,7 @@
 /* Enable this to have a lot of debug printouts */
 #define DEBUG
 
+#include <linux/find_atomic.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
@@ -1201,9 +1202,8 @@ static irqreturn_t interrupt_handler(int irq, void *dev_id)
 exit_handler:
 	spin_unlock(&dc->spin_mutex);
 
-	for (a = 0; a < NOZOMI_MAX_PORTS; a++)
-		if (test_and_clear_bit(a, &dc->flip))
-			tty_flip_buffer_push(&dc->port[a].port);
+	for_each_test_and_clear_bit(a, &dc->flip, NOZOMI_MAX_PORTS)
+		tty_flip_buffer_push(&dc->port[a].port);
 
 	return IRQ_HANDLED;
 none:
-- 
2.43.0