diff options
author | Oliver Neukum <oliver@neukum.org> | 2007-10-23 14:23:13 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-10-25 12:18:44 -0700 |
commit | 54d2bc068fd21bcb096660938bce7c7265613a24 (patch) | |
tree | 6808af091410fea3f2b7e7d06a9cdad322f51ce2 /drivers/usb | |
parent | 439a903a9663c0caa8094f3907ca60069d6c36e7 (diff) | |
download | op-kernel-dev-54d2bc068fd21bcb096660938bce7c7265613a24.zip op-kernel-dev-54d2bc068fd21bcb096660938bce7c7265613a24.tar.gz |
USB: fix locking in idmouse
Pete caused me to lock at buggy drivers in this respect. The idmouse has
a race between open and disconnect. This patch
- solves the open/disconnect race
- switches locking to mutexes
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r-- | drivers/usb/misc/idmouse.c | 45 |
1 files changed, 28 insertions, 17 deletions
diff --git a/drivers/usb/misc/idmouse.c b/drivers/usb/misc/idmouse.c index e6fd024..4bcf7fb 100644 --- a/drivers/usb/misc/idmouse.c +++ b/drivers/usb/misc/idmouse.c @@ -66,6 +66,7 @@ static 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 { @@ -80,7 +81,7 @@ struct usb_idmouse { int open; /* if the port is open or not */ int present; /* if the device is not disconnected */ - struct semaphore sem; /* locks this structure */ + struct mutex lock; /* locks this structure */ }; @@ -213,13 +214,17 @@ 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) + if (!dev) { + mutex_unlock(&open_disc_mutex); return -ENODEV; + } /* lock this device */ - down(&dev->sem); + mutex_lock(&dev->lock); + mutex_unlock(&open_disc_mutex); /* check if already open */ if (dev->open) { @@ -245,7 +250,7 @@ static int idmouse_open(struct inode *inode, struct file *file) error: /* unlock this device */ - up(&dev->sem); + mutex_unlock(&dev->lock); return result; } @@ -258,12 +263,14 @@ static int idmouse_release(struct inode *inode, struct file *file) if (dev == NULL) return -ENODEV; + mutex_lock(&open_disc_mutex); /* lock our device */ - down(&dev->sem); + mutex_lock(&dev->lock); /* are we really open? */ if (dev->open <= 0) { - up(&dev->sem); + mutex_unlock(&dev->lock); + mutex_unlock(&open_disc_mutex); return -ENODEV; } @@ -271,10 +278,12 @@ static int idmouse_release(struct inode *inode, struct file *file) if (!dev->present) { /* the device was unplugged before the file was released */ - up(&dev->sem); + mutex_unlock(&dev->lock); + mutex_unlock(&open_disc_mutex); idmouse_delete(dev); } else { - up(&dev->sem); + mutex_unlock(&dev->lock); + mutex_unlock(&open_disc_mutex); } return 0; } @@ -286,18 +295,18 @@ static ssize_t idmouse_read(struct file *file, char __user *buffer, size_t count int result; /* lock this object */ - down(&dev->sem); + mutex_lock(&dev->lock); /* verify that the device wasn't unplugged */ if (!dev->present) { - up(&dev->sem); + mutex_unlock(&dev->lock); return -ENODEV; } result = simple_read_from_buffer(buffer, count, ppos, dev->bulk_in_buffer, IMGSIZE); /* unlock the device */ - up(&dev->sem); + mutex_unlock(&dev->lock); return result; } @@ -320,7 +329,7 @@ static int idmouse_probe(struct usb_interface *interface, if (dev == NULL) return -ENOMEM; - init_MUTEX(&dev->sem); + mutex_init(&dev->lock); dev->udev = udev; dev->interface = interface; @@ -372,24 +381,26 @@ static void idmouse_disconnect(struct usb_interface *interface) /* get device structure */ dev = usb_get_intfdata(interface); - usb_set_intfdata(interface, NULL); /* give back our minor */ usb_deregister_dev(interface, &idmouse_class); - /* lock it */ - down(&dev->sem); + 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; /* if the device is opened, idmouse_release will clean this up */ if (!dev->open) { - up(&dev->sem); + mutex_unlock(&dev->lock); idmouse_delete(dev); } else { /* unlock */ - up(&dev->sem); + mutex_unlock(&dev->lock); } info("%s disconnected", DRIVER_DESC); |