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@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210421095509.3024-23-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 328d5a7..0ac0371 100644 (file)
--- 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);
 }
 
 /**