Revert "usbtmc: convert to devm_kzalloc"

commit ab21b63e8aedfc73565dd9cdd51eb338341177cb upstream.

This reverts commit e6c7efdcb76f11b04e3d3f71c8d764ab75c9423b.

Turns out it was totally wrong.  The memory is supposed to be bound to
the kref, as the original code was doing correctly, not the
device/driver binding as the devm_kzalloc() would cause.

This fixes an oops when read would be called after the device was
unbound from the driver.

Reported-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 103a6e9ee49d0a473bf29037a352f043a07c6068..4c6d63d4a9e8c8341ae456c7780d93219fe19810 100644 (file)
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -120,6 +120,7 @@ static void usbtmc_delete(struct kref *kref)
        struct usbtmc_device_data *data = to_usbtmc_data(kref);
 
        usb_put_dev(data->usb_dev);
+       kfree(data);
 }
 
 static int usbtmc_open(struct inode *inode, struct file *filp)
@@ -1103,7 +1104,7 @@ static int usbtmc_probe(struct usb_interface *intf,
 
        dev_dbg(&intf->dev, "%s called\n", __func__);
 
-       data = devm_kzalloc(&intf->dev, sizeof(*data), GFP_KERNEL);
+       data = kmalloc(sizeof(*data), GFP_KERNEL);
        if (!data) {
                dev_err(&intf->dev, "Unable to allocate kernel memory\n");
                return -ENOMEM;