leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

USB: idmouse: simplify disconnect handling

Browse Source 
Since commit d4ead16f50 ("USB: prevent char device open/deregister
race") core prevents further calls to open() after usb_deregister_dev()
returns so there's no need to use the interface data for
synchronisation.

This effectively reverts commit 54d2bc068f ("USB: fix locking in
idmouse") with respect to the open-disconnect race.

Note that the driver already uses a present flag to suppress I/O post
disconnect (even if all USB I/O take place at open).

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191105103638.4929-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2019-11-05 11:36:36 +01:00 committed by Greg Kroah-Hartman
parent e76b3bf765
commit 79c36a704a
1 changed files with 2 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/usb/misc/idmouse.c
View File

@ -60,7 +60,6 @@ static const struct usb_device_id idmouse_table[] = {
USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT, value, index, NULL, 0, 1000)
MODULE_DEVICE_TABLE(usb, idmouse_table);
static DEFINE_MUTEX(open_disc_mutex);
/* structure to hold all of our device specific stuff */
struct usb_idmouse {
@ -227,17 +226,13 @@ static int idmouse_open(struct inode *inode, struct file *file)
if (!interface)
return -ENODEV;
mutex_lock(&open_disc_mutex);
/* get the device information block from the interface */
dev = usb_get_intfdata(interface);
if (!dev) {
mutex_unlock(&open_disc_mutex);
if (!dev)
return -ENODEV;
}
/* lock this device */
mutex_lock(&dev->lock);
mutex_unlock(&open_disc_mutex);
/* check if already open */
if (dev->open) {
@ -280,14 +275,12 @@ static int idmouse_release(struct inode *inode, struct file *file)
if (dev == NULL)
return -ENODEV;
mutex_lock(&open_disc_mutex);
/* lock our device */
mutex_lock(&dev->lock);
/* are we really open? */
if (dev->open <= 0) {
mutex_unlock(&dev->lock);
mutex_unlock(&open_disc_mutex);
return -ENODEV;
}
@ -296,11 +289,9 @@ static int idmouse_release(struct inode *inode, struct file *file)
if (!dev->present) {
/* the device was unplugged before the file was released */
mutex_unlock(&dev->lock);
mutex_unlock(&open_disc_mutex);
idmouse_delete(dev);
} else {
mutex_unlock(&dev->lock);
mutex_unlock(&open_disc_mutex);
}
return 0;
}
@ -379,7 +370,6 @@ static int idmouse_probe(struct usb_interface *interface,
if (result) {
/* something prevented us from registering this device */
dev_err(&interface->dev, "Unable to allocate minor number.\n");
usb_set_intfdata(interface, NULL);
idmouse_delete(dev);
return result;
}
@ -392,19 +382,13 @@ static int idmouse_probe(struct usb_interface *interface,
static void idmouse_disconnect(struct usb_interface *interface)
{
struct usb_idmouse *dev;
/* get device structure */
dev = usb_get_intfdata(interface);
struct usb_idmouse *dev = usb_get_intfdata(interface);
/* give back our minor */
usb_deregister_dev(interface, &idmouse_class);
mutex_lock(&open_disc_mutex);
usb_set_intfdata(interface, NULL);
/* lock the device */
mutex_lock(&dev->lock);
mutex_unlock(&open_disc_mutex);
/* prevent device read, write and ioctl */
dev->present = 0;