From: Peter Hurley <peter@hurleysoftware.com>
Date: Thu, 16 Oct 2014 20:54:26 +0000 (-0400)
Subject: serial: core: Remove extra locking in uart_write()
X-Git-Tag: v3.19-rc1~79^2~159
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=64dbee31050d5b93b5fcda25508e4d3c69f6589c;p=linux.git

serial: core: Remove extra locking in uart_write()

uart_start() only claims the port->lock to call __uart_start(),
which does the actual processing. Eliminate the extra acquire/release
in uart_write(); call __uart_start() directly with port->lock already
held.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index e0082b73c198..0282eaaff517 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -537,9 +537,10 @@ static int uart_write(struct tty_struct *tty,
 		count -= c;
 		ret += c;
 	}
+
+	__uart_start(tty);
 	spin_unlock_irqrestore(&port->lock, flags);
 
-	uart_start(tty);
 	return ret;
 }