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USB: iowarrior: drop redundant disconnect mutex

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Drop the redundant disconnect mutex which was introduced after the
open-disconnect race had been addressed generally in USB core by commit
d4ead16f50 ("USB: prevent char device open/deregister race").

Specifically, the rw-semaphore in core guarantees that all calls to
open() will have completed and that no new calls to open() will occur
after usb_deregister_dev() returns. Hence there is no need use the
driver data as an inverted disconnected flag.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191009104846.5925-5-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2019-10-09 12:48:44 +02:00 committed by Greg Kroah-Hartman
parent b5f8d46867
commit 7c5b971d62
1 changed files with 2 additions and 15 deletions
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17
drivers/usb/misc/iowarrior.c
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@ -58,7 +58,6 @@ MODULE_LICENSE("GPL");
static DEFINE_MUTEX(iowarrior_mutex);
static struct usb_driver iowarrior_driver;
static DEFINE_MUTEX(iowarrior_open_disc_lock);
/*--------------*/
/* data */
@ -601,16 +600,13 @@ static int iowarrior_open(struct inode *inode, struct file *file)
return -ENODEV;
}
mutex_lock(&iowarrior_open_disc_lock);
dev = usb_get_intfdata(interface);
if (!dev) {
mutex_unlock(&iowarrior_open_disc_lock);
mutex_unlock(&iowarrior_mutex);
return -ENODEV;
}
mutex_lock(&dev->mutex);
mutex_unlock(&iowarrior_open_disc_lock);
/* Only one process can open each device, no sharing. */
if (dev->opened) {
@ -842,7 +838,6 @@ static int iowarrior_probe(struct usb_interface *interface,
if (retval) {
/* something prevented us from registering this driver */
dev_err(&interface->dev, "Not able to get a minor for this device.\n");
usb_set_intfdata(interface, NULL);
goto error;
}
@ -866,16 +861,8 @@ error:
*/
static void iowarrior_disconnect(struct usb_interface *interface)
{
struct iowarrior *dev;
int minor;
dev = usb_get_intfdata(interface);
mutex_lock(&iowarrior_open_disc_lock);
usb_set_intfdata(interface, NULL);
minor = dev->minor;
mutex_unlock(&iowarrior_open_disc_lock);
/* give back our minor - this will call close() locks need to be dropped at this point*/
struct iowarrior *dev = usb_get_intfdata(interface);
int minor = dev->minor;
usb_deregister_dev(interface, &iowarrior_class);