diff options
| author | Johan Hovold <johan@kernel.org> | 2019-09-26 11:12:26 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-04 11:11:08 +0200 |
| commit | 61991d02fd33698182460bf62dca1b8162e3472b (patch) | |
| tree | 5c551a8b84db17f84e961740a5cb4ad513786167 /drivers/usb/misc | |
| parent | eb7f5a490c5edfe8126f64bc58b9ba2edef0a425 (diff) | |
| download | linux-61991d02fd33698182460bf62dca1b8162e3472b.tar.bz2 | |
USB: usblcd: drop redundant disconnect mutex
Drop the redundant disconnect mutex which was introduced after the
open-disconnect race had been addressed generally in USB core by commit
d4ead16f50f9 ("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/20190926091228.24634-8-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/misc')
| -rw-r--r-- | drivers/usb/misc/usblcd.c | 18 |
1 files changed, 1 insertions, 17 deletions
diff --git a/drivers/usb/misc/usblcd.c b/drivers/usb/misc/usblcd.c index aa982d3ca36b..b898650a5570 100644 --- a/drivers/usb/misc/usblcd.c +++ b/drivers/usb/misc/usblcd.c @@ -37,9 +37,6 @@ static const struct usb_device_id id_table[] = { }; MODULE_DEVICE_TABLE(usb, id_table); -static DEFINE_MUTEX(open_disc_mutex); - - struct usb_lcd { struct usb_device *udev; /* init: probe_lcd */ struct usb_interface *interface; /* the interface for @@ -95,17 +92,10 @@ static int lcd_open(struct inode *inode, struct file *file) return -ENODEV; } - mutex_lock(&open_disc_mutex); dev = usb_get_intfdata(interface); - if (!dev) { - mutex_unlock(&open_disc_mutex); - mutex_unlock(&lcd_mutex); - return -ENODEV; - } /* increment our usage count for the device */ kref_get(&dev->kref); - mutex_unlock(&open_disc_mutex); /* grab a power reference */ r = usb_autopm_get_interface(interface); @@ -388,7 +378,6 @@ static int lcd_probe(struct usb_interface *interface, /* 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; } @@ -434,14 +423,9 @@ static int lcd_resume(struct usb_interface *intf) static void lcd_disconnect(struct usb_interface *interface) { - struct usb_lcd *dev; + struct usb_lcd *dev = usb_get_intfdata(interface); int minor = interface->minor; - mutex_lock(&open_disc_mutex); - dev = usb_get_intfdata(interface); - usb_set_intfdata(interface, NULL); - mutex_unlock(&open_disc_mutex); - /* give back our minor */ usb_deregister_dev(interface, &lcd_class); |