#include <asm/uaccess.h>
-static int max_loop = 8;
-static struct loop_device *loop_dev;
-static struct gendisk **disks;
+static LIST_HEAD(loop_devices);
+static DEFINE_MUTEX(loop_devices_mutex);
/*
* Transfer functions
if (unlikely((loff_t)x != size))
return -EFBIG;
- set_capacity(disks[lo->lo_number], x);
+ set_capacity(lo->lo_disk, x);
return 0;
}
lo->lo_queue->queuedata = lo;
lo->lo_queue->unplug_fn = loop_unplug;
- set_capacity(disks[lo->lo_number], size);
+ set_capacity(lo->lo_disk, size);
bd_set_size(bdev, size << 9);
set_blocksize(bdev, lo_blocksize);
lo->lo_device = NULL;
lo->lo_backing_file = NULL;
lo->lo_flags = 0;
- set_capacity(disks[lo->lo_number], 0);
- invalidate_bdev(bdev, 0);
+ set_capacity(lo->lo_disk, 0);
+ invalidate_bdev(bdev);
bd_set_size(bdev, 0);
mapping_set_gfp_mask(mapping, lo->old_gfp_mask);
lo->lo_state = Lo_unbound;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
- invalidate_bdev(bdev, 0);
- set_capacity(disks[lo->lo_number], 0);
+ invalidate_bdev(bdev);
+ set_capacity(lo->lo_disk, 0);
bd_set_size(bdev, 0);
mapping_set_gfp_mask(filp->f_mapping, gfp);
lo->lo_state = Lo_unbound;
}
#endif
+static struct loop_device *loop_find_dev(int number)
+{
+ struct loop_device *lo;
+
+ list_for_each_entry(lo, &loop_devices, lo_list) {
+ if (lo->lo_number == number)
+ return lo;
+ }
+ return NULL;
+}
+
+static struct loop_device *loop_init_one(int i);
static int lo_open(struct inode *inode, struct file *file)
{
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
lo->lo_refcnt++;
mutex_unlock(&lo->lo_ctl_mutex);
+ mutex_lock(&loop_devices_mutex);
+ if (!loop_find_dev(lo->lo_number + 1))
+ loop_init_one(lo->lo_number + 1);
+ mutex_unlock(&loop_devices_mutex);
+
return 0;
}
/*
* And now the modules code and kernel interface.
*/
+static int max_loop;
module_param(max_loop, int, 0);
-MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)");
+MODULE_PARM_DESC(max_loop, "obsolete, loop device is created on-demand");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
xfer_funcs[n] = NULL;
- for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
+ list_for_each_entry(lo, &loop_devices, lo_list) {
mutex_lock(&lo->lo_ctl_mutex);
if (lo->lo_encryption == xfer)
EXPORT_SYMBOL(loop_register_transfer);
EXPORT_SYMBOL(loop_unregister_transfer);
-static int __init loop_init(void)
+static struct loop_device *loop_init_one(int i)
+{
+ struct loop_device *lo;
+ struct gendisk *disk;
+
+ lo = kzalloc(sizeof(*lo), GFP_KERNEL);
+ if (!lo)
+ goto out;
+
+ lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
+ if (!lo->lo_queue)
+ goto out_free_dev;
+
+ disk = lo->lo_disk = alloc_disk(1);
+ if (!disk)
+ goto out_free_queue;
+
+ mutex_init(&lo->lo_ctl_mutex);
+ lo->lo_number = i;
+ lo->lo_thread = NULL;
+ init_waitqueue_head(&lo->lo_event);
+ spin_lock_init(&lo->lo_lock);
+ disk->major = LOOP_MAJOR;
+ disk->first_minor = i;
+ disk->fops = &lo_fops;
+ disk->private_data = lo;
+ disk->queue = lo->lo_queue;
+ sprintf(disk->disk_name, "loop%d", i);
+ add_disk(disk);
+ list_add_tail(&lo->lo_list, &loop_devices);
+ return lo;
+
+out_free_queue:
+ blk_cleanup_queue(lo->lo_queue);
+out_free_dev:
+ kfree(lo);
+out:
+ return ERR_PTR(-ENOMEM);
+}
+
+static void loop_del_one(struct loop_device *lo)
{
- int i;
+ del_gendisk(lo->lo_disk);
+ blk_cleanup_queue(lo->lo_queue);
+ put_disk(lo->lo_disk);
+ list_del(&lo->lo_list);
+ kfree(lo);
+}
- if (max_loop < 1 || max_loop > 256) {
- printk(KERN_WARNING "loop: invalid max_loop (must be between"
- " 1 and 256), using default (8)\n");
- max_loop = 8;
- }
+static struct kobject *loop_probe(dev_t dev, int *part, void *data)
+{
+ unsigned int number = dev & MINORMASK;
+ struct loop_device *lo;
+
+ mutex_lock(&loop_devices_mutex);
+ lo = loop_find_dev(number);
+ if (lo == NULL)
+ lo = loop_init_one(number);
+ mutex_unlock(&loop_devices_mutex);
+
+ *part = 0;
+ if (IS_ERR(lo))
+ return (void *)lo;
+ else
+ return &lo->lo_disk->kobj;
+}
+
+static int __init loop_init(void)
+{
+ struct loop_device *lo;
if (register_blkdev(LOOP_MAJOR, "loop"))
return -EIO;
+ blk_register_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS,
+ THIS_MODULE, loop_probe, NULL, NULL);
- loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL);
- if (!loop_dev)
- goto out_mem1;
- memset(loop_dev, 0, max_loop * sizeof(struct loop_device));
+ lo = loop_init_one(0);
+ if (IS_ERR(lo))
+ goto out;
- disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL);
- if (!disks)
- goto out_mem2;
+ if (max_loop) {
+ printk(KERN_INFO "loop: the max_loop option is obsolete "
+ "and will be removed in March 2008\n");
- for (i = 0; i < max_loop; i++) {
- disks[i] = alloc_disk(1);
- if (!disks[i])
- goto out_mem3;
}
-
- for (i = 0; i < max_loop; i++) {
- struct loop_device *lo = &loop_dev[i];
- struct gendisk *disk = disks[i];
-
- memset(lo, 0, sizeof(*lo));
- lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
- if (!lo->lo_queue)
- goto out_mem4;
- mutex_init(&lo->lo_ctl_mutex);
- lo->lo_number = i;
- lo->lo_thread = NULL;
- init_waitqueue_head(&lo->lo_event);
- spin_lock_init(&lo->lo_lock);
- disk->major = LOOP_MAJOR;
- disk->first_minor = i;
- disk->fops = &lo_fops;
- sprintf(disk->disk_name, "loop%d", i);
- disk->private_data = lo;
- disk->queue = lo->lo_queue;
- }
-
- /* We cannot fail after we call this, so another loop!*/
- for (i = 0; i < max_loop; i++)
- add_disk(disks[i]);
- printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop);
+ printk(KERN_INFO "loop: module loaded\n");
return 0;
-out_mem4:
- while (i--)
- blk_cleanup_queue(loop_dev[i].lo_queue);
- i = max_loop;
-out_mem3:
- while (i--)
- put_disk(disks[i]);
- kfree(disks);
-out_mem2:
- kfree(loop_dev);
-out_mem1:
+out:
unregister_blkdev(LOOP_MAJOR, "loop");
printk(KERN_ERR "loop: ran out of memory\n");
return -ENOMEM;
}
-static void loop_exit(void)
+static void __exit loop_exit(void)
{
- int i;
+ struct loop_device *lo, *next;
- for (i = 0; i < max_loop; i++) {
- del_gendisk(disks[i]);
- blk_cleanup_queue(loop_dev[i].lo_queue);
- put_disk(disks[i]);
- }
+ list_for_each_entry_safe(lo, next, &loop_devices, lo_list)
+ loop_del_one(lo);
+
+ blk_unregister_region(MKDEV(LOOP_MAJOR, 0), 1UL << MINORBITS);
if (unregister_blkdev(LOOP_MAJOR, "loop"))
printk(KERN_WARNING "loop: cannot unregister blkdev\n");
-
- kfree(disks);
- kfree(loop_dev);
}
module_init(loop_init);
projects / powerpc.git / blobdiff