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/*
* linux/drivers/block/loop.c
*
* Written by Theodore Ts'o, 3/29/93
*
* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
* permitted under the GNU General Public License.
*
* DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
* more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
*
* Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
* Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
*
* Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
*
* Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
*
* Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
*
* Loadable modules and other fixes by AK, 1998
*
* Make real block number available to downstream transfer functions, enables
* CBC (and relatives) mode encryption requiring unique IVs per data block.
* Reed H. Petty, rhp@draper.net
*
* Maximum number of loop devices now dynamic via max_loop module parameter.
* Russell Kroll <rkroll@exploits.org> 19990701
*
* Maximum number of loop devices when compiled-in now selectable by passing
* max_loop=<1-255> to the kernel on boot.
* Erik I. Bolsų, <eriki@himolde.no>, Oct 31, 1999
*
* Completely rewrite request handling to be make_request_fn style and
* non blocking, pushing work to a helper thread. Lots of fixes from
* Al Viro too.
* Jens Axboe <axboe@suse.de>, Nov 2000
*
* Still To Fix:
* - Advisory locking is ignored here.
* - Should use an own CAP_* category instead of CAP_SYS_ADMIN
*
* WARNING/FIXME:
* - The block number as IV passing to low level transfer functions is broken:
* it passes the underlying device's block number instead of the
* offset. This makes it change for a given block when the file is
* moved/restored/copied and also doesn't work over NFS.
* AV, Feb 12, 2000: we pass the logical block number now. It fixes the
* problem above. Encryption modules that used to rely on the old scheme
* should just call ->i_mapping->bmap() to calculate the physical block
* number.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/major.h>
#include <linux/wait.h>
#include <linux/blk.h>
#include <linux/blkpg.h>
#include <linux/init.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/smp_lock.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/loop.h>
#define MAJOR_NR LOOP_MAJOR
static int max_loop = 8;
static struct loop_device *loop_dev;
static int *loop_sizes;
static int *loop_blksizes;
static devfs_handle_t devfs_handle; /* For the directory */
/*
* Transfer functions
*/
static int transfer_none(struct loop_device *lo, int cmd, char *raw_buf,
char *loop_buf, int size, int real_block)
{
if (raw_buf != loop_buf) {
if (cmd == READ)
memcpy(loop_buf, raw_buf, size);
else
memcpy(raw_buf, loop_buf, size);
}
return 0;
}
static int transfer_xor(struct loop_device *lo, int cmd, char *raw_buf,
char *loop_buf, int size, int real_block)
{
char *in, *out, *key;
int i, keysize;
if (cmd == READ) {
in = raw_buf;
out = loop_buf;
} else {
in = loop_buf;
out = raw_buf;
}
key = lo->lo_encrypt_key;
keysize = lo->lo_encrypt_key_size;
for (i = 0; i < size; i++)
*out++ = *in++ ^ key[(i & 511) % keysize];
return 0;
}
static int none_status(struct loop_device *lo, struct loop_info *info)
{
lo->lo_flags |= LO_FLAGS_BH_REMAP;
return 0;
}
static int xor_status(struct loop_device *lo, struct loop_info *info)
{
if (info->lo_encrypt_key_size <= 0)
return -EINVAL;
return 0;
}
struct loop_func_table none_funcs = {
number: LO_CRYPT_NONE,
transfer: transfer_none,
init: none_status,
};
struct loop_func_table xor_funcs = {
number: LO_CRYPT_XOR,
transfer: transfer_xor,
init: xor_status
};
/* xfer_funcs[0] is special - its release function is never called */
struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
&none_funcs,
&xor_funcs
};
#define MAX_DISK_SIZE 1024*1024*1024
static unsigned long compute_loop_size(struct loop_device *lo, struct dentry * lo_dentry, kdev_t lodev)
{
if (S_ISREG(lo_dentry->d_inode->i_mode))
return (lo_dentry->d_inode->i_size - lo->lo_offset) >> BLOCK_SIZE_BITS;
if (blk_size[MAJOR(lodev)])
return blk_size[MAJOR(lodev)][MINOR(lodev)] -
(lo->lo_offset >> BLOCK_SIZE_BITS);
return MAX_DISK_SIZE;
}
static void figure_loop_size(struct loop_device *lo)
{
loop_sizes[lo->lo_number] = compute_loop_size(lo,
lo->lo_backing_file->f_dentry,
lo->lo_device);
}
static int lo_send(struct loop_device *lo, struct buffer_head *bh, int bsize,
loff_t pos)
{
struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
struct address_space *mapping = file->f_dentry->d_inode->i_mapping;
struct address_space_operations *aops = mapping->a_ops;
struct page *page;
char *kaddr, *data;
unsigned long index;
unsigned size, offset;
int len;
down(&mapping->host->i_sem);
index = pos >> PAGE_CACHE_SHIFT;
offset = pos & (PAGE_CACHE_SIZE - 1);
len = bh->b_size;
data = bh->b_data;
while (len > 0) {
int IV = index * (PAGE_CACHE_SIZE/bsize) + offset/bsize;
int transfer_result;
size = PAGE_CACHE_SIZE - offset;
if (size > len)
size = len;
page = grab_cache_page(mapping, index);
if (!page)
goto fail;
if (aops->prepare_write(file, page, offset, offset+size))
goto unlock;
kaddr = page_address(page);
flush_dcache_page(page);
transfer_result = lo_do_transfer(lo, WRITE, kaddr + offset, data, size, IV);
if (transfer_result) {
/*
* The transfer failed, but we still write the data to
* keep prepare/commit calls balanced.
*/
printk(KERN_ERR "loop: transfer error block %ld\n", index);
memset(kaddr + offset, 0, size);
}
if (aops->commit_write(file, page, offset, offset+size))
goto unlock;
if (transfer_result)
goto unlock;
data += size;
len -= size;
offset = 0;
index++;
pos += size;
UnlockPage(page);
page_cache_release(page);
}
up(&mapping->host->i_sem);
return 0;
unlock:
UnlockPage(page);
page_cache_release(page);
fail:
up(&mapping->host->i_sem);
return -1;
}
struct lo_read_data {
struct loop_device *lo;
char *data;
int bsize;
};
static int lo_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size)
{
char *kaddr;
unsigned long count = desc->count;
struct lo_read_data *p = (struct lo_read_data*)desc->buf;
struct loop_device *lo = p->lo;
int IV = page->index * (PAGE_CACHE_SIZE/p->bsize) + offset/p->bsize;
if (size > count)
size = count;
kaddr = kmap(page);
if (lo_do_transfer(lo, READ, kaddr + offset, p->data, size, IV)) {
size = 0;
printk(KERN_ERR "loop: transfer error block %ld\n",page->index);
desc->error = -EINVAL;
}
kunmap(page);
desc->count = count - size;
desc->written += size;
p->data += size;
return size;
}
static int lo_receive(struct loop_device *lo, struct buffer_head *bh, int bsize,
loff_t pos)
{
struct lo_read_data cookie;
read_descriptor_t desc;
struct file *file;
cookie.lo = lo;
cookie.data = bh->b_data;
cookie.bsize = bsize;
desc.written = 0;
desc.count = bh->b_size;
desc.buf = (char*)&cookie;
desc.error = 0;
spin_lock_irq(&lo->lo_lock);
file = lo->lo_backing_file;
spin_unlock_irq(&lo->lo_lock);
do_generic_file_read(file, &pos, &desc, lo_read_actor);
return desc.error;
}
static inline int loop_get_bs(struct loop_device *lo)
{
int bs = 0;
if (blksize_size[MAJOR(lo->lo_device)])
bs = blksize_size[MAJOR(lo->lo_device)][MINOR(lo->lo_device)];
if (!bs)
bs = BLOCK_SIZE;
return bs;
}
static inline unsigned long loop_get_iv(struct loop_device *lo,
unsigned long sector)
{
int bs = loop_get_bs(lo);
unsigned long offset, IV;
IV = sector / (bs >> 9) + lo->lo_offset / bs;
offset = ((sector % (bs >> 9)) << 9) + lo->lo_offset % bs;
if (offset >= bs)
IV++;
return IV;
}
static int do_bh_filebacked(struct loop_device *lo, struct buffer_head *bh, int rw)
{
loff_t pos;
int ret;
pos = ((loff_t) bh->b_rsector << 9) + lo->lo_offset;
if (rw == WRITE)
ret = lo_send(lo, bh, loop_get_bs(lo), pos);
else
ret = lo_receive(lo, bh, loop_get_bs(lo), pos);
return ret;
}
static void loop_end_io_transfer(struct buffer_head *bh, int uptodate);
static void loop_put_buffer(struct buffer_head *bh)
{
/*
* check b_end_io, may just be a remapped bh and not an allocated one
*/
if (bh && bh->b_end_io == loop_end_io_transfer) {
__free_page(bh->b_page);
kmem_cache_free(bh_cachep, bh);
}
}
/*
* Add buffer_head to back of pending list
*/
static void loop_add_bh(struct loop_device *lo, struct buffer_head *bh)
{
unsigned long flags;
spin_lock_irqsave(&lo->lo_lock, flags);
if (lo->lo_bhtail) {
lo->lo_bhtail->b_reqnext = bh;
lo->lo_bhtail = bh;
} else
lo->lo_bh = lo->lo_bhtail = bh;
spin_unlock_irqrestore(&lo->lo_lock, flags);
up(&lo->lo_bh_mutex);
}
/*
* Grab first pending buffer
*/
static struct buffer_head *loop_get_bh(struct loop_device *lo)
{
struct buffer_head *bh;
spin_lock_irq(&lo->lo_lock);
if ((bh = lo->lo_bh)) {
if (bh == lo->lo_bhtail)
lo->lo_bhtail = NULL;
lo->lo_bh = bh->b_reqnext;
bh->b_reqnext = NULL;
}
spin_unlock_irq(&lo->lo_lock);
return bh;
}
/*
* when buffer i/o has completed. if BH_Dirty is set, this was a WRITE
* and lo->transfer stuff has already been done. if not, it was a READ
* so queue it for the loop thread and let it do the transfer out of
* b_end_io context (we don't want to do decrypt of a page with irqs
* disabled)
*/
static void loop_end_io_transfer(struct buffer_head *bh, int uptodate)
{
struct loop_device *lo = &loop_dev[MINOR(bh->b_dev)];
if (!uptodate || test_bit(BH_Dirty, &bh->b_state)) {
struct buffer_head *rbh = bh->b_private;
rbh->b_end_io(rbh, uptodate);
if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex);
loop_put_buffer(bh);
} else
loop_add_bh(lo, bh);
}
static struct buffer_head *loop_get_buffer(struct loop_device *lo,
struct buffer_head *rbh)
{
struct buffer_head *bh;
/*
* for xfer_funcs that can operate on the same bh, do that
*/
if (lo->lo_flags & LO_FLAGS_BH_REMAP) {
bh = rbh;
goto out_bh;
}
do {
bh = kmem_cache_alloc(bh_cachep, SLAB_NOIO);
if (bh)
break;
run_task_queue(&tq_disk);
schedule_timeout(HZ);
} while (1);
memset(bh, 0, sizeof(*bh));
bh->b_size = rbh->b_size;
bh->b_dev = rbh->b_rdev;
bh->b_state = (1 << BH_Req) | (1 << BH_Mapped) | (1 << BH_Lock);
/*
* easy way out, although it does waste some memory for < PAGE_SIZE
* blocks... if highmem bounce buffering can get away with it,
* so can we :-)
*/
do {
bh->b_page = alloc_page(GFP_NOIO);
if (bh->b_page)
break;
run_task_queue(&tq_disk);
schedule_timeout(HZ);
} while (1);
bh->b_data = page_address(bh->b_page);
bh->b_end_io = loop_end_io_transfer;
bh->b_private = rbh;
init_waitqueue_head(&bh->b_wait);
out_bh:
bh->b_rsector = rbh->b_rsector + (lo->lo_offset >> 9);
spin_lock_irq(&lo->lo_lock);
bh->b_rdev = lo->lo_device;
spin_unlock_irq(&lo->lo_lock);
return bh;
}
static int loop_make_request(request_queue_t *q, int rw, struct buffer_head *rbh)
{
struct buffer_head *bh = NULL;
struct loop_device *lo;
unsigned long IV;
if (!buffer_locked(rbh))
BUG();
if (MINOR(rbh->b_rdev) >= max_loop)
goto out;
lo = &loop_dev[MINOR(rbh->b_rdev)];
spin_lock_irq(&lo->lo_lock);
if (lo->lo_state != Lo_bound)
goto inactive;
atomic_inc(&lo->lo_pending);
spin_unlock_irq(&lo->lo_lock);
if (rw == WRITE) {
if (lo->lo_flags & LO_FLAGS_READ_ONLY)
goto err;
} else if (rw == READA) {
rw = READ;
} else if (rw != READ) {
printk(KERN_ERR "loop: unknown command (%d)\n", rw);
goto err;
}
#if CONFIG_HIGHMEM
rbh = create_bounce(rw, rbh);
#endif
/*
* file backed, queue for loop_thread to handle
*/
if (lo->lo_flags & LO_FLAGS_DO_BMAP) {
/*
* rbh locked at this point, noone else should clear
* the dirty flag
*/
if (rw == WRITE)
set_bit(BH_Dirty, &rbh->b_state);
loop_add_bh(lo, rbh);
return 0;
}
/*
* piggy old buffer on original, and submit for I/O
*/
bh = loop_get_buffer(lo, rbh);
IV = loop_get_iv(lo, rbh->b_rsector);
if (rw == WRITE) {
set_bit(BH_Dirty, &bh->b_state);
if (lo_do_transfer(lo, WRITE, bh->b_data, rbh->b_data,
bh->b_size, IV))
goto err;
}
generic_make_request(rw, bh);
return 0;
err:
if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex);
loop_put_buffer(bh);
out:
buffer_IO_error(rbh);
return 0;
inactive:
spin_unlock_irq(&lo->lo_lock);
goto out;
}
static inline void loop_handle_bh(struct loop_device *lo,struct buffer_head *bh)
{
int ret;
/*
* For block backed loop, we know this is a READ
*/
if (lo->lo_flags & LO_FLAGS_DO_BMAP) {
int rw = !!test_and_clear_bit(BH_Dirty, &bh->b_state);
ret = do_bh_filebacked(lo, bh, rw);
bh->b_end_io(bh, !ret);
} else {
struct buffer_head *rbh = bh->b_private;
unsigned long IV = loop_get_iv(lo, rbh->b_rsector);
ret = lo_do_transfer(lo, READ, bh->b_data, rbh->b_data,
bh->b_size, IV);
rbh->b_end_io(rbh, !ret);
loop_put_buffer(bh);
}
}
/*
* worker thread that handles reads/writes to file backed loop devices,
* to avoid blocking in our make_request_fn. it also does loop decrypting
* on reads for block backed loop, as that is too heavy to do from
* b_end_io context where irqs may be disabled.
*/
static int loop_thread(void *data)
{
struct loop_device *lo = data;
struct buffer_head *bh;
daemonize();
exit_files(current);
sprintf(current->comm, "loop%d", lo->lo_number);
spin_lock_irq(¤t->sigmask_lock);
sigfillset(¤t->blocked);
flush_signals(current);
spin_unlock_irq(¤t->sigmask_lock);
current->policy = SCHED_OTHER;
current->nice = -20;
spin_lock_irq(&lo->lo_lock);
lo->lo_state = Lo_bound;
atomic_inc(&lo->lo_pending);
spin_unlock_irq(&lo->lo_lock);
current->flags |= PF_NOIO;
/*
* up sem, we are running
*/
up(&lo->lo_sem);
for (;;) {
down_interruptible(&lo->lo_bh_mutex);
/*
* could be upped because of tear-down, not because of
* pending work
*/
if (!atomic_read(&lo->lo_pending))
break;
bh = loop_get_bh(lo);
if (!bh) {
printk("loop: missing bh\n");
continue;
}
loop_handle_bh(lo, bh);
/*
* upped both for pending work and tear-down, lo_pending
* will hit zero then
*/
if (atomic_dec_and_test(&lo->lo_pending))
break;
}
up(&lo->lo_sem);
return 0;
}
static int loop_set_fd(struct loop_device *lo, struct file *lo_file, kdev_t dev,
unsigned int arg)
{
struct file *file;
struct inode *inode;
kdev_t lo_device;
int lo_flags = 0;
int error;
int bs;
MOD_INC_USE_COUNT;
error = -EBUSY;
if (lo->lo_state != Lo_unbound)
goto out;
error = -EBADF;
file = fget(arg);
if (!file)
goto out;
error = -EINVAL;
inode = file->f_dentry->d_inode;
if (!(file->f_mode & FMODE_WRITE))
lo_flags |= LO_FLAGS_READ_ONLY;
if (S_ISBLK(inode->i_mode)) {
lo_device = inode->i_rdev;
if (lo_device == dev) {
error = -EBUSY;
goto out;
}
} else if (S_ISREG(inode->i_mode)) {
struct address_space_operations *aops = inode->i_mapping->a_ops;
/*
* If we can't read - sorry. If we only can't write - well,
* it's going to be read-only.
*/
if (!aops->readpage)
goto out_putf;
if (!aops->prepare_write || !aops->commit_write)
lo_flags |= LO_FLAGS_READ_ONLY;
lo_device = inode->i_dev;
lo_flags |= LO_FLAGS_DO_BMAP;
error = 0;
} else
goto out_putf;
get_file(file);
if (IS_RDONLY (inode) || is_read_only(lo_device)
|| !(lo_file->f_mode & FMODE_WRITE))
lo_flags |= LO_FLAGS_READ_ONLY;
set_device_ro(dev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
lo->lo_device = lo_device;
lo->lo_flags = lo_flags;
lo->lo_backing_file = file;
lo->transfer = NULL;
lo->ioctl = NULL;
figure_loop_size(lo);
lo->old_gfp_mask = inode->i_mapping->gfp_mask;
inode->i_mapping->gfp_mask = GFP_NOIO;
bs = 0;
if (blksize_size[MAJOR(lo_device)])
bs = blksize_size[MAJOR(lo_device)][MINOR(lo_device)];
if (!bs)
bs = BLOCK_SIZE;
set_blocksize(dev, bs);
lo->lo_bh = lo->lo_bhtail = NULL;
kernel_thread(loop_thread, lo, CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
down(&lo->lo_sem);
fput(file);
return 0;
out_putf:
fput(file);
out:
MOD_DEC_USE_COUNT;
return error;
}
static int loop_release_xfer(struct loop_device *lo)
{
int err = 0;
if (lo->lo_encrypt_type) {
struct loop_func_table *xfer= xfer_funcs[lo->lo_encrypt_type];
if (xfer && xfer->release)
err = xfer->release(lo);
if (xfer && xfer->unlock)
xfer->unlock(lo);
lo->lo_encrypt_type = 0;
}
return err;
}
static int loop_init_xfer(struct loop_device *lo, int type,struct loop_info *i)
{
int err = 0;
if (type) {
struct loop_func_table *xfer = xfer_funcs[type];
if (xfer->init)
err = xfer->init(lo, i);
if (!err) {
lo->lo_encrypt_type = type;
if (xfer->lock)
xfer->lock(lo);
}
}
return err;
}
static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
{
struct file *filp = lo->lo_backing_file;
int gfp = lo->old_gfp_mask;
if (lo->lo_state != Lo_bound)
return -ENXIO;
if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */
return -EBUSY;
if (filp==NULL)
return -EINVAL;
spin_lock_irq(&lo->lo_lock);
lo->lo_state = Lo_rundown;
if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex);
spin_unlock_irq(&lo->lo_lock);
down(&lo->lo_sem);
lo->lo_backing_file = NULL;
loop_release_xfer(lo);
lo->transfer = NULL;
lo->ioctl = NULL;
lo->lo_device = 0;
lo->lo_encrypt_type = 0;
lo->lo_offset = 0;
lo->lo_encrypt_key_size = 0;
lo->lo_flags = 0;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_name, 0, LO_NAME_SIZE);
loop_sizes[lo->lo_number] = 0;
invalidate_bdev(bdev, 0);
filp->f_dentry->d_inode->i_mapping->gfp_mask = gfp;
lo->lo_state = Lo_unbound;
fput(filp);
MOD_DEC_USE_COUNT;
return 0;
}
static int loop_set_status(struct loop_device *lo, struct loop_info *arg)
{
struct loop_info info;
int err;
unsigned int type;
if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
if (lo->lo_state != Lo_bound)
return -ENXIO;
if (copy_from_user(&info, arg, sizeof (struct loop_info)))
return -EFAULT;
if ((unsigned int) info.lo_encrypt_key_size > LO_KEY_SIZE)
return -EINVAL;
type = info.lo_encrypt_type;
if (type >= MAX_LO_CRYPT || xfer_funcs[type] == NULL)
return -EINVAL;
if (type == LO_CRYPT_XOR && info.lo_encrypt_key_size == 0)
return -EINVAL;
err = loop_release_xfer(lo);
if (!err)
err = loop_init_xfer(lo, type, &info);
if (err)
return err;
lo->lo_offset = info.lo_offset;
strncpy(lo->lo_name, info.lo_name, LO_NAME_SIZE);
lo->transfer = xfer_funcs[type]->transfer;
lo->ioctl = xfer_funcs[type]->ioctl;
lo->lo_encrypt_key_size = info.lo_encrypt_key_size;
lo->lo_init[0] = info.lo_init[0];
lo->lo_init[1] = info.lo_init[1];
if (info.lo_encrypt_key_size) {
memcpy(lo->lo_encrypt_key, info.lo_encrypt_key,
info.lo_encrypt_key_size);
lo->lo_key_owner = current->uid;
}
figure_loop_size(lo);
return 0;
}
static int loop_get_status(struct loop_device *lo, struct loop_info *arg)
{
struct loop_info info;
struct file *file = lo->lo_backing_file;
if (lo->lo_state != Lo_bound)
return -ENXIO;
if (!arg)
return -EINVAL;
memset(&info, 0, sizeof(info));
info.lo_number = lo->lo_number;
info.lo_device = kdev_t_to_nr(file->f_dentry->d_inode->i_dev);
info.lo_inode = file->f_dentry->d_inode->i_ino;
info.lo_rdevice = kdev_t_to_nr(lo->lo_device);
info.lo_offset = lo->lo_offset;
info.lo_flags = lo->lo_flags;
strncpy(info.lo_name, lo->lo_name, LO_NAME_SIZE);
info.lo_encrypt_type = lo->lo_encrypt_type;
if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
info.lo_encrypt_key_size = lo->lo_encrypt_key_size;
memcpy(info.lo_encrypt_key, lo->lo_encrypt_key,
lo->lo_encrypt_key_size);
}
return copy_to_user(arg, &info, sizeof(info)) ? -EFAULT : 0;
}
static int lo_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct loop_device *lo;
int dev, err;
if (!inode)
return -EINVAL;
if (MAJOR(inode->i_rdev) != MAJOR_NR) {
printk(KERN_WARNING "lo_ioctl: pseudo-major != %d\n",
MAJOR_NR);
return -ENODEV;
}
dev = MINOR(inode->i_rdev);
if (dev >= max_loop)
return -ENODEV;
lo = &loop_dev[dev];
down(&lo->lo_ctl_mutex);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, file, inode->i_rdev, arg);
break;
case LOOP_CLR_FD:
err = loop_clr_fd(lo, inode->i_bdev);
break;
case LOOP_SET_STATUS:
err = loop_set_status(lo, (struct loop_info *) arg);
break;
case LOOP_GET_STATUS:
err = loop_get_status(lo, (struct loop_info *) arg);
break;
case BLKGETSIZE:
if (lo->lo_state != Lo_bound) {
err = -ENXIO;
break;
}
err = put_user((unsigned long)loop_sizes[lo->lo_number] << 1, (unsigned long *) arg);
break;
case BLKGETSIZE64:
if (lo->lo_state != Lo_bound) {
err = -ENXIO;
break;
}
err = put_user((u64)loop_sizes[lo->lo_number] << 10, (u64*)arg);
break;
case BLKBSZGET:
case BLKBSZSET:
err = blk_ioctl(inode->i_rdev, cmd, arg);
break;
default:
err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
}
up(&lo->lo_ctl_mutex);
return err;
}
static int lo_open(struct inode *inode, struct file *file)
{
struct loop_device *lo;
int dev, type;
if (!inode)
return -EINVAL;
if (MAJOR(inode->i_rdev) != MAJOR_NR) {
printk(KERN_WARNING "lo_open: pseudo-major != %d\n", MAJOR_NR);
return -ENODEV;
}
dev = MINOR(inode->i_rdev);
if (dev >= max_loop)
return -ENODEV;
lo = &loop_dev[dev];
MOD_INC_USE_COUNT;
down(&lo->lo_ctl_mutex);
type = lo->lo_encrypt_type;
if (type && xfer_funcs[type] && xfer_funcs[type]->lock)
xfer_funcs[type]->lock(lo);
lo->lo_refcnt++;
up(&lo->lo_ctl_mutex);
return 0;
}
static int lo_release(struct inode *inode, struct file *file)
{
struct loop_device *lo;
int dev, type;
if (!inode)
return 0;
if (MAJOR(inode->i_rdev) != MAJOR_NR) {
printk(KERN_WARNING "lo_release: pseudo-major != %d\n",
MAJOR_NR);
return 0;
}
dev = MINOR(inode->i_rdev);
if (dev >= max_loop)
return 0;
lo = &loop_dev[dev];
down(&lo->lo_ctl_mutex);
type = lo->lo_encrypt_type;
--lo->lo_refcnt;
if (xfer_funcs[type] && xfer_funcs[type]->unlock)
xfer_funcs[type]->unlock(lo);
up(&lo->lo_ctl_mutex);
MOD_DEC_USE_COUNT;
return 0;
}
static struct block_device_operations lo_fops = {
owner: THIS_MODULE,
open: lo_open,
release: lo_release,
ioctl: lo_ioctl,
};
/*
* And now the modules code and kernel interface.
*/
MODULE_PARM(max_loop, "i");
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-255)");
MODULE_LICENSE("GPL");
int loop_register_transfer(struct loop_func_table *funcs)
{
if ((unsigned)funcs->number > MAX_LO_CRYPT || xfer_funcs[funcs->number])
return -EINVAL;
xfer_funcs[funcs->number] = funcs;
return 0;
}
int loop_unregister_transfer(int number)
{
struct loop_device *lo;
if ((unsigned)number >= MAX_LO_CRYPT)
return -EINVAL;
for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
int type = lo->lo_encrypt_type;
if (type == number) {
xfer_funcs[type]->release(lo);
lo->transfer = NULL;
lo->lo_encrypt_type = 0;
}
}
xfer_funcs[number] = NULL;
return 0;
}
EXPORT_SYMBOL(loop_register_transfer);
EXPORT_SYMBOL(loop_unregister_transfer);
int __init loop_init(void)
{
int i;
if ((max_loop < 1) || (max_loop > 255)) {
printk(KERN_WARNING "loop: invalid max_loop (must be between"
" 1 and 255), using default (8)\n");
max_loop = 8;
}
if (devfs_register_blkdev(MAJOR_NR, "loop", &lo_fops)) {
printk(KERN_WARNING "Unable to get major number %d for loop"
" device\n", MAJOR_NR);
return -EIO;
}
devfs_handle = devfs_mk_dir(NULL, "loop", NULL);
devfs_register_series(devfs_handle, "%u", max_loop, DEVFS_FL_DEFAULT,
MAJOR_NR, 0,
S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
&lo_fops, NULL);
loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL);
if (!loop_dev)
return -ENOMEM;
loop_sizes = kmalloc(max_loop * sizeof(int), GFP_KERNEL);
if (!loop_sizes)
goto out_sizes;
loop_blksizes = kmalloc(max_loop * sizeof(int), GFP_KERNEL);
if (!loop_blksizes)
goto out_blksizes;
blk_queue_make_request(BLK_DEFAULT_QUEUE(MAJOR_NR), loop_make_request);
for (i = 0; i < max_loop; i++) {
struct loop_device *lo = &loop_dev[i];
memset(lo, 0, sizeof(struct loop_device));
init_MUTEX(&lo->lo_ctl_mutex);
init_MUTEX_LOCKED(&lo->lo_sem);
init_MUTEX_LOCKED(&lo->lo_bh_mutex);
lo->lo_number = i;
spin_lock_init(&lo->lo_lock);
}
memset(loop_sizes, 0, max_loop * sizeof(int));
memset(loop_blksizes, 0, max_loop * sizeof(int));
blk_size[MAJOR_NR] = loop_sizes;
blksize_size[MAJOR_NR] = loop_blksizes;
for (i = 0; i < max_loop; i++)
register_disk(NULL, MKDEV(MAJOR_NR, i), 1, &lo_fops, 0);
printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop);
return 0;
out_sizes:
kfree(loop_dev);
out_blksizes:
kfree(loop_sizes);
printk(KERN_ERR "loop: ran out of memory\n");
return -ENOMEM;
}
void loop_exit(void)
{
devfs_unregister(devfs_handle);
if (devfs_unregister_blkdev(MAJOR_NR, "loop"))
printk(KERN_WARNING "loop: cannot unregister blkdev\n");
kfree(loop_dev);
kfree(loop_sizes);
kfree(loop_blksizes);
}
module_init(loop_init);
module_exit(loop_exit);
#ifndef MODULE
static int __init max_loop_setup(char *str)
{
max_loop = simple_strtol(str, NULL, 0);
return 1;
}
__setup("max_loop=", max_loop_setup);
#endif
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