From 2e57480b2a717916510b0c23b2851398a4cbd958 Mon Sep 17 00:00:00 2001
From: Jiri Kosina <jkosina@suse.cz>
Date: Thu, 25 Mar 2010 14:15:11 +0100
Subject: [PATCH] HID: remove BKL from hidraw

Remove BKL from hidraw, which is possible through fixing the
locking of minors_lock mutex properly -- it is now used to
guard all accessess to hidraw_table[], preventing it to becoming
NULL unexpectedly by unregistering the device.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/hid/hidraw.c | 41 +++++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index d04476700b7b..589dac5b5f56 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -105,38 +105,48 @@ out:
 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 {
 	unsigned int minor = iminor(file->f_path.dentry->d_inode);
-	/* FIXME: What stops hidraw_table going NULL */
-	struct hid_device *dev = hidraw_table[minor]->hid;
+	struct hid_device *dev;
 	__u8 *buf;
 	int ret = 0;
 
-	if (!dev->hid_output_raw_report)
-		return -ENODEV;
+	mutex_lock(&minors_lock);
+	dev = hidraw_table[minor]->hid;
+
+	if (!dev->hid_output_raw_report) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	if (count > HID_MAX_BUFFER_SIZE) {
 		printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 				task_pid_nr(current));
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
 
 	if (count < 2) {
 		printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 				task_pid_nr(current));
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
 
 	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	if (copy_from_user(buf, buffer, count)) {
 		ret = -EFAULT;
-		goto out;
+		goto out_free;
 	}
 
 	ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
-out:
+out_free:
 	kfree(buf);
+out:
+	mutex_unlock(&minors_lock);
 	return ret;
 }
 
@@ -164,7 +174,6 @@ static int hidraw_open(struct inode *inode, struct file *file)
 		goto out;
 	}
 
-	lock_kernel();
 	mutex_lock(&minors_lock);
 	if (!hidraw_table[minor]) {
 		printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
@@ -196,7 +205,6 @@ static int hidraw_open(struct inode *inode, struct file *file)
 
 out_unlock:
 	mutex_unlock(&minors_lock);
-	unlock_kernel();
 out:
 	return err;
 
@@ -237,11 +245,12 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
 	struct inode *inode = file->f_path.dentry->d_inode;
 	unsigned int minor = iminor(inode);
 	long ret = 0;
-	/* FIXME: What stops hidraw_table going NULL */
-	struct hidraw *dev = hidraw_table[minor];
+	struct hidraw *dev;
 	void __user *user_arg = (void __user*) arg;
 
-	lock_kernel();
+	mutex_lock(&minors_lock);
+	dev = hidraw_table[minor];
+
 	switch (cmd) {
 		case HIDIOCGRDESCSIZE:
 			if (put_user(dev->hid->rsize, (int __user *)arg))
@@ -314,7 +323,7 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
 
 		ret = -ENOTTY;
 	}
-	unlock_kernel();
+	mutex_unlock(&minors_lock);
 	return ret;
 }
 
-- 
2.20.1