HID: hidraw: don't deallocate memory when it is in use

When a device is unplugged, wait for all processes that have opened the device
to close before deallocating the device.

Signed-off-by: Ratan Nalumasu <ratan@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 3b6f7bf5a77e1407d787742886d4d10867890f82..c46c5f1037f4bfaed739e5ca9d164df326fbeb0b 100644 (file)
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -42,6 +42,7 @@ static struct cdev hidraw_cdev;
 static struct class *hidraw_class;
 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
 static DEFINE_MUTEX(minors_lock);
+static void drop_ref(struct hidraw *hid, int exists_bit);
 
 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 {
@@ -113,7 +114,7 @@ static ssize_t hidraw_send_report(struct file *file, const char __user *buffer,
        __u8 *buf;
        int ret = 0;
 
-       if (!hidraw_table[minor]) {
+       if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
                ret = -ENODEV;
                goto out;
        }
@@ -261,7 +262,7 @@ static int hidraw_open(struct inode *inode, struct file *file)
        }
 
        mutex_lock(&minors_lock);
-       if (!hidraw_table[minor]) {
+       if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
                err = -ENODEV;
                goto out_unlock;
        }
@@ -298,36 +299,12 @@ out:
 static int hidraw_release(struct inode * inode, struct file * file)
 {
        unsigned int minor = iminor(inode);
-       struct hidraw *dev;
        struct hidraw_list *list = file->private_data;
-       int ret;
-       int i;
-
-       mutex_lock(&minors_lock);
-       if (!hidraw_table[minor]) {
-               ret = -ENODEV;
-               goto unlock;
-       }
 
+       drop_ref(hidraw_table[minor], 0);
        list_del(&list->node);
-       dev = hidraw_table[minor];
-       if (!--dev->open) {
-               if (list->hidraw->exist) {
-                       hid_hw_power(dev->hid, PM_HINT_NORMAL);
-                       hid_hw_close(dev->hid);
-               } else {
-                       kfree(list->hidraw);
-               }
-       }
-
-       for (i = 0; i < HIDRAW_BUFFER_SIZE; ++i)
-               kfree(list->buffer[i].value);
        kfree(list);
-       ret = 0;
-unlock:
-       mutex_unlock(&minors_lock);
-
-       return ret;
+       return 0;
 }
 
 static long hidraw_ioctl(struct file *file, unsigned int cmd,
@@ -529,21 +506,7 @@ EXPORT_SYMBOL_GPL(hidraw_connect);
 void hidraw_disconnect(struct hid_device *hid)
 {
        struct hidraw *hidraw = hid->hidraw;
-
-       mutex_lock(&minors_lock);
-       hidraw->exist = 0;
-
-       device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
-
-       hidraw_table[hidraw->minor] = NULL;
-
-       if (hidraw->open) {
-               hid_hw_close(hid);
-               wake_up_interruptible(&hidraw->wait);
-       } else {
-               kfree(hidraw);
-       }
-       mutex_unlock(&minors_lock);
+       drop_ref(hidraw, 1);
 }
 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 
@@ -585,3 +548,23 @@ void hidraw_exit(void)
        unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 
 }
+
+static void drop_ref(struct hidraw *hidraw, int exists_bit)
+{
+       mutex_lock(&minors_lock);
+       if (exists_bit) {
+               hid_hw_close(hidraw->hid);
+               hidraw->exist = 0;
+               if (hidraw->open)
+                       wake_up_interruptible(&hidraw->wait);
+       } else {
+               --hidraw->open;
+       }
+
+       if (!hidraw->open && !hidraw->exist) {
+               device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
+               hidraw_table[hidraw->minor] = NULL;
+               kfree(hidraw);
+       }
+       mutex_unlock(&minors_lock);
+}