linux-kernel - [PATCH v2 23/35] usb: cdc-acm: optimize acm

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Message-Id: <20231203193307.542794-22-yury.norov@gmail.com>
Date:   Sun,  3 Dec 2023 11:32:55 -0800
From:   Yury Norov <yury.norov@...il.com>
To:     linux-kernel@...r.kernel.org, Oliver Neukum <oneukum@...e.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org
Cc:     Yury Norov <yury.norov@...il.com>, Jan Kara <jack@...e.cz>,
        Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
        Matthew Wilcox <willy@...radead.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Maxim Kuvyrkov <maxim.kuvyrkov@...aro.org>,
        Alexey Klimov <klimov.linux@...il.com>,
        Bart Van Assche <bvanassche@....org>,
        Sergey Shtylyov <s.shtylyov@....ru>
Subject: [PATCH v2 23/35] usb: cdc-acm: optimize acm_softint()

acm_softint(), uses for-loop to traverse urbs_in_error_delay bitmap
bit by bit to find and clear set bits.

We can do it better by using for_each_test_and_clear_bit(), because it
doesn't test already clear bits.

Signed-off-by: Yury Norov <yury.norov@...il.com>
Acked-by: Oliver Neukum <oneukum@...e.com>
---
 drivers/usb/class/cdc-acm.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index a1f4e1ead97f..8664b63050b0 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -613,9 +613,8 @@ static void acm_softint(struct work_struct *work)
 	}
 
 	if (test_and_clear_bit(ACM_ERROR_DELAY, &acm->flags)) {
-		for (i = 0; i < acm->rx_buflimit; i++)
-			if (test_and_clear_bit(i, &acm->urbs_in_error_delay))
-				acm_submit_read_urb(acm, i, GFP_KERNEL);
+		for_each_test_and_clear_bit(i, &acm->urbs_in_error_delay, acm->rx_buflimit)
+			acm_submit_read_urb(acm, i, GFP_KERNEL);
 	}
 
 	if (test_and_clear_bit(EVENT_TTY_WAKEUP, &acm->flags))
-- 
2.40.1