linux-kernel - [PATCH 04/26] serial: amba-pl010: drop low-latency workaround

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210421095509.3024-5-johan@kernel.org>
Date:   Wed, 21 Apr 2021 11:54:47 +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>,
        Russell King <linux@...linux.org.uk>
Subject: [PATCH 04/26] serial: amba-pl010: drop low-latency workaround

Commit 2389b272168c ("[ARM] 4417/1: Serial: Fix AMBA drivers locking")
worked around the infamous low_latency behaviour of
tty_flip_buffer_push() by simply dropping and reacquiring the port lock
in the interrupt handler.

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: Russell King <linux@...linux.org.uk>
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/tty/serial/amba-pl010.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c
index 3f96edfe569c..e744b953ca34 100644
--- a/drivers/tty/serial/amba-pl010.c
+++ b/drivers/tty/serial/amba-pl010.c
@@ -159,9 +159,7 @@ static void pl010_rx_chars(struct uart_amba_port *uap)
 	ignore_char:
 		status = readb(uap->port.membase + UART01x_FR);
 	}
-	spin_unlock(&uap->port.lock);
 	tty_flip_buffer_push(&uap->port.state->port);
-	spin_lock(&uap->port.lock);
 }
 
 static void pl010_tx_chars(struct uart_amba_port *uap)
-- 
2.26.3