int __init
blktap_ring_init(void)
{
dev_t dev = 0;
int err;
cdev_init(&blktap_ring_cdev, &blktap_ring_file_operations);
blktap_ring_cdev.owner = THIS_MODULE;
err = alloc_chrdev_region(&dev, 0, MAX_BLKTAP_DEVICE, "blktap2");
if (err < 0) {
BTERR("error registering ring devices: %d\n", err);
return err;
}
err = cdev_add(&blktap_ring_cdev, dev, MAX_BLKTAP_DEVICE);
if (err) {
BTERR("error adding ring device: %d\n", err);
unregister_chrdev_region(dev, MAX_BLKTAP_DEVICE);
return err;
}
blktap_ring_major = MAJOR(dev);
BTINFO("blktap ring major: %d\n", blktap_ring_major);
return 0;
}
static void
blktap_control_free(void)
{
int i;
for (i = 0; i < MAX_BLKTAP_DEVICE; i++)
blktap_control_destroy_device(blktaps[i]);
if (blktap_control_registered)
if (misc_deregister(&blktap_misc) < 0)
BTERR("misc_deregister failed for control device");
}
static int __init
blktap_control_init(void)
{
int err;
err = misc_register(&blktap_misc);
if (err) {
BTERR("misc_register failed for control device");
return err;
}
blktap_control_registered = 1;
return 0;
}
static struct blktap *
blktap_control_allocate_tap(void)
{
int err, minor;
struct blktap *tap;
/*
* This is called only from the ioctl, which
* means we should always have interrupts enabled.
*/
BUG_ON(irqs_disabled());
spin_lock_irq(&blktap_control_lock);
for (minor = 0; minor < MAX_BLKTAP_DEVICE; minor++) {
tap = blktaps[minor];
if (!tap)
goto found;
if (!tap->dev_inuse) {
blktap_control_initialize_tap(tap);
goto found;
}
}
tap = NULL;
found:
spin_unlock_irq(&blktap_control_lock);
if (!tap) {
tap = blktap_control_create_tap();
if (!tap)
return NULL;
}
err = blktap_ring_create(tap);
if (err) {
BTERR("ring creation failed: %d\n", err);
clear_bit(BLKTAP_CONTROL, &tap->dev_inuse);
return NULL;
}
BTINFO("allocated tap %p\n", tap);
return tap;
}
static int
blktap_control_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
unsigned long dev;
struct blktap *tap;
switch (cmd) {
case BLKTAP2_IOCTL_ALLOC_TAP: {
struct blktap_handle h;
tap = blktap_control_allocate_tap();
if (!tap) {
BTERR("error allocating device\n");
return -ENOMEM;
}
h.ring = ring_major;
h.device = device_major;
h.minor = tap->minor;
if (copy_to_user((struct blktap_handle __user *)arg,
&h, sizeof(h))) {
blktap_control_destroy_device(tap);
return -EFAULT;
}
return 0;
}
case BLKTAP2_IOCTL_FREE_TAP:
dev = arg;
if (dev >= MAX_BLKTAP_DEVICE || !blktaps[dev])
return -EINVAL;
blktap_control_destroy_device(blktaps[dev]);
return 0;
}
return -ENOIOCTLCMD;
}
