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>

1 files changed, 26 insertions, 43 deletions

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 3b6f7bf5a77e..c46c5f1037f4 100644
--- 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);
+}