linux-kernel - [PATCH 22/26] serial: sifive: drop low-latency workaround

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Message-Id: <20210421095509.3024-23-johan@kernel.org>
Date:   Wed, 21 Apr 2021 11:55:05 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Jiri Slaby <jirislaby@...nel.org>, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>
Subject: [PATCH 22/26] serial: sifive: drop low-latency workaround

The sifive driver has always carried an unnecessary workaround for the
infamous low_latency behaviour of tty_flip_buffer_push() which had been
removed years before the driver was added by commit 45c054d0815b ("tty:
serial: add driver for the SiFive UART").

Specifically, since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks around.

Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/tty/serial/sifive.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 328d5a78792f..0ac0371f943b 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -448,9 +448,7 @@ static void __ssp_receive_chars(struct sifive_serial_port *ssp)
 		uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL);
 	}
 
-	spin_unlock(&ssp->port.lock);
 	tty_flip_buffer_push(&ssp->port.state->port);
-	spin_lock(&ssp->port.lock);
 }
 
 /**
-- 
2.26.3