From: Oliver Neukum <[EMAIL PROTECTED]>
Iet's kill BKL where we can. This is relative to the last patch to the
skeleton driver.
Signed-off-by: Oliver Neukum <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/usb-skeleton.c | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 962b28c..8432bf1 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -34,6 +34,9 @@ static struct usb_device_id skel_table [] = {
};
MODULE_DEVICE_TABLE(usb, skel_table);
+/* to prevent a race between open and disconnect */
+static DEFINE_MUTEX(skel_open_lock);
+
/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE 192
@@ -80,8 +83,10 @@ static int skel_open(struct inode *inode, struct file *file)
subminor = iminor(inode);
+ mutex_lock(&skel_open_lock);
interface = usb_find_interface(&skel_driver, subminor);
if (!interface) {
+ mutex_unlock(&skel_open_lock);
err ("%s - error, can't find device for minor %d",
__FUNCTION__, subminor);
retval = -ENODEV;
@@ -90,12 +95,15 @@ static int skel_open(struct inode *inode, struct file *file)
dev = usb_get_intfdata(interface);
if (!dev) {
+ mutex_unlock(&skel_open_lock);
retval = -ENODEV;
goto exit;
}
/* increment our usage count for the device */
kref_get(&dev->kref);
+ /* now we can drop the lock */
+ mutex_unlock(&skel_open_lock);
/* prevent the device from being autosuspended */
retval = usb_autopm_get_interface(interface);
@@ -361,14 +369,14 @@ static void skel_disconnect(struct usb_interface
*interface)
int minor = interface->minor;
/* prevent skel_open() from racing skel_disconnect() */
- lock_kernel();
+ mutex_lock(&skel_open_lock);
dev = usb_get_intfdata(interface);
usb_set_intfdata(interface, NULL);
/* give back our minor */
usb_deregister_dev(interface, &skel_class);
- unlock_kernel();
+ mutex_unlock(&skel_open_lock);
/* prevent more I/O from starting */
mutex_lock(&dev->io_mutex);
--
1.5.1.2
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