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From:   Jiri Slaby <jslaby@suse.cz>
To:     gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiri Slaby <jslaby@suse.cz>
Subject: [PATCH 11/44] tty: 8250, use ms_to_ktime
Date:   Tue,  2 Mar 2021 07:21:41 +0100
Message-Id: <20210302062214.29627-11-jslaby@suse.cz>
In-Reply-To: <20210302062214.29627-1-jslaby@suse.cz>
References: <20210302062214.29627-1-jslaby@suse.cz>
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This really eliminates multiplications from the assembly. I would have
thought they are optimized by inlining ktime_set, but not on x86_64 with
gcc 10.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/serial/8250/8250_port.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index b0af13074cd3..167c1e3e53bc 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1487,11 +1487,7 @@ static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
 
 static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
 {
-	long sec = msec / 1000;
-	long nsec = (msec % 1000) * 1000000;
-	ktime_t t = ktime_set(sec, nsec);
-
-	hrtimer_start(hrt, t, HRTIMER_MODE_REL);
+	hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL);
 }
 
 static void __stop_tx_rs485(struct uart_8250_port *p)
-- 
2.30.1