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>

1 files 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;
 }