linux-kernel - [PATCH] powerpc: hvc_close() unsigned hp->count cannot be negative

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Message-ID: <4931387C.4000001@gmail.com>
Date:	Sat, 29 Nov 2008 07:41:32 -0500
From:	roel kluin <roel.kluin@...il.com>
To:	benh@...nel.crashing.org, linuxppc-dev@...abs.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc: hvc_close() unsigned hp->count cannot be negative

unsigned hp->count cannot be negative

Signed-off-by: Roel Kluin <roel.kluin@...il.com>
---
Similar to the previous patch but with lock. For hvc_struct, see
vi drivers/char/hvc_console.h +47

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 5b819b1..337f6c6 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -366,7 +366,8 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
 	hp = tty->driver_data;
 	spin_lock_irqsave(&hp->lock, flags);
 
-	if (--hp->count == 0) {
+	if (hp->count == 1) {
+		hp->count--;
 		/* We are done with the tty pointer now. */
 		hp->tty = NULL;
 		spin_unlock_irqrestore(&hp->lock, flags);
@@ -384,7 +385,9 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
 		 */
 		tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
 	} else {
-		if (hp->count < 0)
+		if (hp->count > 1)
+			hp->count--;
+		else
 			printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
 				hp->vtermno, hp->count);
 		spin_unlock_irqrestore(&hp->lock, flags);

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