From: Jonathan Corbet <corbet@lwn.net>
Date: Thu, 15 May 2008 17:58:31 +0000 (-0600)
Subject: phonedev: cdev lock_kernel() pushdown
X-Git-Tag: v2.6.27-rc1~1103^2~122
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16750c2f32e3fd879fce787a13900f11633ef9af;p=linux-2.6

phonedev: cdev lock_kernel() pushdown

phone_open() looks OK, but I don't trust the subsidiary drivers (and ixj in
particular).

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
---

diff --git a/drivers/telephony/phonedev.c b/drivers/telephony/phonedev.c
index bcea8d9b71..4d74ba36c3 100644
--- a/drivers/telephony/phonedev.c
+++ b/drivers/telephony/phonedev.c
@@ -23,6 +23,7 @@
 #include <linux/errno.h>
 #include <linux/phonedev.h>
 #include <linux/init.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
 
@@ -53,6 +54,7 @@ static int phone_open(struct inode *inode, struct file *file)
 	if (minor >= PHONE_NUM_DEVICES)
 		return -ENODEV;
 
+	lock_kernel();
 	mutex_lock(&phone_lock);
 	p = phone_device[minor];
 	if (p)
@@ -79,6 +81,7 @@ static int phone_open(struct inode *inode, struct file *file)
 	fops_put(old_fops);
 end:
 	mutex_unlock(&phone_lock);
+	unlock_kernel();
 	return err;
 }