| From c78a1aa532afbfcce1326b2dcb469a22b2ecd0b8 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 8 Mar 2022 12:51:53 +0100 |
| Subject: serial: samsung_tty: do not unlock port->lock for uart_write_wakeup() |
| |
| From: Jiri Slaby <jslaby@suse.cz> |
| |
| [ Upstream commit 988c7c00691008ea1daaa1235680a0da49dab4e8 ] |
| |
| The commit c15c3747ee32 (serial: samsung: fix potential soft lockup |
| during uart write) added an unlock of port->lock before |
| uart_write_wakeup() and a lock after it. It was always problematic to |
| write data from tty_ldisc_ops::write_wakeup and it was even documented |
| that way. We fixed the line disciplines to conform to this recently. |
| So if there is still a missed one, we should fix them instead of this |
| workaround. |
| |
| On the top of that, s3c24xx_serial_tx_dma_complete() in this driver |
| still holds the port->lock while calling uart_write_wakeup(). |
| |
| So revert the wrap added by the commit above. |
| |
| Cc: Thomas Abraham <thomas.abraham@linaro.org> |
| Cc: Kyungmin Park <kyungmin.park@samsung.com> |
| Cc: Hyeonkook Kim <hk619.kim@samsung.com> |
| Signed-off-by: Jiri Slaby <jslaby@suse.cz> |
| Link: https://lore.kernel.org/r/20220308115153.4225-1-jslaby@suse.cz |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/tty/serial/samsung_tty.c | 5 +---- |
| 1 file changed, 1 insertion(+), 4 deletions(-) |
| |
| diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c |
| index ca084c10d0bb..78f01ddab1c6 100644 |
| --- a/drivers/tty/serial/samsung_tty.c |
| +++ b/drivers/tty/serial/samsung_tty.c |
| @@ -922,11 +922,8 @@ static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport) |
| return; |
| } |
| |
| - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) { |
| - spin_unlock(&port->lock); |
| + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) |
| uart_write_wakeup(port); |
| - spin_lock(&port->lock); |
| - } |
| |
| if (uart_circ_empty(xmit)) |
| s3c24xx_serial_stop_tx(port); |
| -- |
| 2.35.1 |
| |