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[23/26] serial: sunsu: drop low-latency workaround

Message ID	20210421095509.3024-24-johan@kernel.org
State	New
Headers	show Return-Path: <linux-serial-owner@kernel.org> From: Johan Hovold <johan@kernel.org> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org>, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold <johan@kernel.org>, "David S. Miller" <davem@davemloft.net> Subject: [PATCH 23/26] serial: sunsu: drop low-latency workaround Date: Wed, 21 Apr 2021 11:55:06 +0200 Message-Id: <20210421095509.3024-24-johan@kernel.org> In-Reply-To: <20210421095509.3024-1-johan@kernel.org> References: <20210421095509.3024-1-johan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	tty: drop low-latency workarounds \| expand [00/26] tty: drop low-latency workarounds [01/26] tty: mxser: drop low-latency workaround [02/26] serial: altera_jtaguart: drop low-latency workaround [03/26] serial: altera_uart: drop low-latency workaround [04/26] serial: amba-pl010: drop low-latency workaround [05/26] serial: amba-pl011: drop low-latency workaround [06/26] serial: apbuart: drop low-latency workaround [07/26] serial: ar933x: drop low-latency workaround [08/26] serial: arc_uart: drop low-latency workaround [09/26] serial: atmel_serial: drop low-latency workaround [10/26] serial: bcm63xx: drop low-latency workaround [11/26] serial: icom: drop low-latency workaround [12/26] serial: lpc32xx_hs: drop low-latency workaround [13/26] serial: mcf: drop low-latency workaround [14/26] serial: meson: drop low-latency workaround [15/26] serial: mpc52xx_uart: drop low-latency workaround [16/26] serial: msm_serial: drop low-latency workaround [17/26] serial: owl: drop low-latency workaround [18/26] serial: rda: drop low-latency workaround [19/26] serial: rp2: drop low-latency workaround [20/26] serial: sa1100: drop low-latency workaround [21/26] serial: txx9: drop low-latency workaround [22/26] serial: sifive: drop low-latency workaround [23/26] serial: sunsu: drop low-latency workaround [24/26] serial: timbuart: drop low-latency workaround [25/26] serial: vt8500: drop low-latency workaround [26/26] serial: xilinx_uartps: drop low-latency workaround

Commit Message

Johan Hovold April 21, 2021, 9:55 a.m. UTC

The sunsu driver has been carrying a workaround for the infamous
low_latency behaviour of tty_flip_buffer_push() by dropping and
reacquiring the port lock in the interrupt handler since 2004.

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: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/tty/serial/sunsu.c | 4 ----
 1 file changed, 4 deletions(-)

diff mbox series

Patch

diff --git a/drivers/tty/serial/sunsu.c b/drivers/tty/serial/sunsu.c
index 319e5ceb6130..12c2468f2b0e 100644
--- a/drivers/tty/serial/sunsu.c
+++ b/drivers/tty/serial/sunsu.c
@@ -466,12 +466,8 @@  static irqreturn_t sunsu_serial_interrupt(int irq, void *dev_id)
 		if (status & UART_LSR_THRE)
 			transmit_chars(up);
 
-		spin_unlock_irqrestore(&up->port.lock, flags);
-
 		tty_flip_buffer_push(&up->port.state->port);
 
-		spin_lock_irqsave(&up->port.lock, flags);
-
 	} while (!(serial_in(up, UART_IIR) & UART_IIR_NO_INT));
 
 	spin_unlock_irqrestore(&up->port.lock, flags);