linux-kernel - [PATCH 2/4] net/irda: Hold port lock while bumping blocked

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Date:	Tue,  5 Mar 2013 11:09:05 -0500
From:	Peter Hurley <peter@...leysoftware.com>
To:	David Miller <davem@...emloft.net>,
	Samuel Ortiz <samuel@...tiz.org>
Cc:	Sasha Levin <sasha.levin@...cle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	netdev@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
	linux-kernel@...r.kernel.org,
	Peter Hurley <peter@...leysoftware.com>
Subject: [PATCH 2/4] net/irda: Hold port lock while bumping blocked_open

Although tty_lock() already protects concurrent update to
blocked_open, that fails to meet the separation-of-concerns between
tty_port and tty.

Signed-off-by: Peter Hurley <peter@...leysoftware.com>
---
 net/irda/ircomm/ircomm_tty.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 1721dc7..d282bbe 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -317,8 +317,8 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
 	spin_lock_irqsave(&port->lock, flags);
 	if (!tty_hung_up_p(filp))
 		port->count--;
-	spin_unlock_irqrestore(&port->lock, flags);
 	port->blocked_open++;
+	spin_unlock_irqrestore(&port->lock, flags);
 
 	while (1) {
 		if (tty->termios.c_cflag & CBAUD)
@@ -362,8 +362,8 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
 	spin_lock_irqsave(&port->lock, flags);
 	if (!tty_hung_up_p(filp))
 		port->count++;
-	spin_unlock_irqrestore(&port->lock, flags);
 	port->blocked_open--;
+	spin_unlock_irqrestore(&port->lock, flags);
 
 	IRDA_DEBUG(1, "%s(%d):block_til_ready after blocking on %s open_count=%d\n",
 	      __FILE__, __LINE__, tty->driver->name, port->count);
-- 
1.8.1.2

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