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Subject[PATCH 3.2 017/149] HID: hidraw: put old deallocation mechanism in place
3.2.52-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Kosina <jkosina@suse.cz>

commit df0cfd6990347c20ae031f3f34137cba274f1972 upstream.

This basically reverts commit 4fe9f8e203fda. It causes multiple problems,
namely:

- after rmmod/modprobe cycle of bus driver, the input is not claimed any
more. This is likely because of misplaced hid_hw_close()
- it causes memory corruption on hidraw_list

As original patch author is not responding to requests to fix his patch,
and the original deallocation mechanism is not exposing any problems, I
am reverting back to it.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/hid/hidraw.c | 69 ++++++++++++++++++++++++++++++++--------------------
1 file changed, 43 insertions(+), 26 deletions(-)

--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -42,7 +42,6 @@ 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)
{
@@ -114,7 +113,7 @@ static ssize_t hidraw_send_report(struct
__u8 *buf;
int ret = 0;

- if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
+ if (!hidraw_table[minor]) {
ret = -ENODEV;
goto out;
}
@@ -262,7 +261,7 @@ static int hidraw_open(struct inode *ino
}

mutex_lock(&minors_lock);
- if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
+ if (!hidraw_table[minor]) {
err = -ENODEV;
goto out_unlock;
}
@@ -299,12 +298,36 @@ 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);
- return 0;
+ ret = 0;
+unlock:
+ mutex_unlock(&minors_lock);
+
+ return ret;
}

static long hidraw_ioctl(struct file *file, unsigned int cmd,
@@ -506,7 +529,21 @@ EXPORT_SYMBOL_GPL(hidraw_connect);
void hidraw_disconnect(struct hid_device *hid)
{
struct hidraw *hidraw = hid->hidraw;
- drop_ref(hidraw, 1);
+
+ 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);
}
EXPORT_SYMBOL_GPL(hidraw_disconnect);

@@ -555,23 +592,3 @@ 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);
-}


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