HID: fix locking in hidraw_open()

As open needs to sleep hidraw was wrong to call it with a spinlock held.
Furthermore, open can of course fail which needs to be handled.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 16 insertions, 14 deletions

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 894d52e05bf9..7685ae6808c4 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -38,7 +38,7 @@ static int hidraw_major;
 static struct cdev hidraw_cdev;
 static struct class *hidraw_class;
 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
-static DEFINE_SPINLOCK(minors_lock);
+static DEFINE_MUTEX(minors_lock);
 
 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 {
@@ -159,13 +159,13 @@ static int hidraw_open(struct inode *inode, struct file *file)
         struct hidraw_list *list;
         int err = 0;
 
-        lock_kernel();
         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
                 err = -ENOMEM;
                 goto out;
         }
 
-        spin_lock(&minors_lock);
+        lock_kernel();
+        mutex_lock(&minors_lock);
         if (!hidraw_table[minor]) {
                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
                                 minor);
@@ -180,13 +180,16 @@ static int hidraw_open(struct inode *inode, struct file *file)
         file->private_data = list;
 
         dev = hidraw_table[minor];
-        if (!dev->open++)
-                dev->hid->ll_driver->open(dev->hid);
+        if (!dev->open++) {
+                err = dev->hid->ll_driver->open(dev->hid);
+                if (err < 0)
+                        dev->open--;
+        }
 
 out_unlock:
-        spin_unlock(&minors_lock);
-out:
+        mutex_unlock(&minors_lock);
         unlock_kernel();
+out:
         return err;
 
 }
@@ -310,7 +313,7 @@ int hidraw_connect(struct hid_device *hid)
 
         result = -EINVAL;
 
-        spin_lock(&minors_lock);
+        mutex_lock(&minors_lock);
 
         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
                 if (hidraw_table[minor])
@@ -320,9 +323,8 @@ int hidraw_connect(struct hid_device *hid)
                 break;
         }
 
-        spin_unlock(&minors_lock);
-
         if (result) {
+                mutex_unlock(&minors_lock);
                 kfree(dev);
                 goto out;
         }
@@ -331,14 +333,14 @@ int hidraw_connect(struct hid_device *hid)
                                  NULL, "%s%d", "hidraw", minor);
 
         if (IS_ERR(dev->dev)) {
-                spin_lock(&minors_lock);
                 hidraw_table[minor] = NULL;
-                spin_unlock(&minors_lock);
+                mutex_unlock(&minors_lock);
                 result = PTR_ERR(dev->dev);
                 kfree(dev);
                 goto out;
         }
 
+        mutex_unlock(&minors_lock);
         init_waitqueue_head(&dev->wait);
         INIT_LIST_HEAD(&dev->list);
 
@@ -360,9 +362,9 @@ void hidraw_disconnect(struct hid_device *hid)
 
         hidraw->exist = 0;
 
-        spin_lock(&minors_lock);
+        mutex_lock(&minors_lock);
         hidraw_table[hidraw->minor] = NULL;
-        spin_unlock(&minors_lock);
+        mutex_unlock(&minors_lock);
 
         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));