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yaml
---
r: 54640
b: refs/heads/master
c: 7328508
h: refs/heads/master
v: v3
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Ken Chen authored and Linus Torvalds committed May 8, 2007
1 parent b543c73 commit 4cd389c
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Showing 3 changed files with 113 additions and 75 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 4f911d64e04a44c47985be30f978fb3c2efcee0c
refs/heads/master: 73285082745045bcd64333c1fbaa88f8490f2626
184 changes: 110 additions & 74 deletions trunk/drivers/block/loop.c
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Original file line number Diff line number Diff line change
Expand Up @@ -77,9 +77,8 @@

#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
Expand Down Expand Up @@ -183,7 +182,7 @@ figure_loop_size(struct loop_device *lo)
if (unlikely((loff_t)x != size))
return -EFBIG;

set_capacity(disks[lo->lo_number], x);
set_capacity(lo->lo_disk, x);
return 0;
}

Expand Down Expand Up @@ -812,7 +811,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
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);
Expand All @@ -832,7 +831,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
lo->lo_device = NULL;
lo->lo_backing_file = NULL;
lo->lo_flags = 0;
set_capacity(disks[lo->lo_number], 0);
set_capacity(lo->lo_disk, 0);
invalidate_bdev(bdev);
bd_set_size(bdev, 0);
mapping_set_gfp_mask(mapping, lo->old_gfp_mask);
Expand Down Expand Up @@ -918,7 +917,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
invalidate_bdev(bdev);
set_capacity(disks[lo->lo_number], 0);
set_capacity(lo->lo_disk, 0);
bd_set_size(bdev, 0);
mapping_set_gfp_mask(filp->f_mapping, gfp);
lo->lo_state = Lo_unbound;
Expand Down Expand Up @@ -1322,6 +1321,18 @@ static long lo_compat_ioctl(struct file *file, unsigned int cmd, unsigned long a
}
#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;
Expand All @@ -1330,6 +1341,11 @@ static int lo_open(struct inode *inode, struct file *file)
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;
}

Expand Down Expand Up @@ -1357,8 +1373,9 @@ static struct block_device_operations lo_fops = {
/*
* 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);

Expand All @@ -1383,7 +1400,7 @@ int loop_unregister_transfer(int number)

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)
Expand All @@ -1398,91 +1415,110 @@ int loop_unregister_transfer(int number)
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);
Expand Down
2 changes: 2 additions & 0 deletions trunk/include/linux/loop.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,8 @@ struct loop_device {
wait_queue_head_t lo_event;

request_queue_t *lo_queue;
struct gendisk *lo_disk;
struct list_head lo_list;
};

#endif /* __KERNEL__ */
Expand Down

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