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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>
This commit is contained in:
Ratan Nalumasu 2012-09-22 11:46:30 -07:00 committed by Jiri Kosina
parent cead24c118
commit 4fe9f8e203
1 changed files with 26 additions and 43 deletions
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69
drivers/hid/hidraw.c
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@ -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);
}