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35a82d1a53
Looks like locking can be optimised quite a lot. Increase lock widths slightly so lo_lock is taken fewer times per request. Also it was quite trivial to cover lo_pending with that lock, and remove the atomic requirement. This also makes memory ordering explicitly correct, which is nice (not that I particularly saw any mem ordering bugs). Test was reading 4 250MB files in parallel on ext2-on-tmpfs filesystem (1K block size, 4K page size). System is 2 socket Xeon with HT (4 thread). intel:/home/npiggin# umount /dev/loop0 ; mount /dev/loop0 /mnt/loop ; /usr/bin/time ./mtloop.sh Before: 0.24user 5.51system 0:02.84elapsed 202%CPU (0avgtext+0avgdata 0maxresident)k 0.19user 5.52system 0:02.88elapsed 198%CPU (0avgtext+0avgdata 0maxresident)k 0.19user 5.57system 0:02.89elapsed 198%CPU (0avgtext+0avgdata 0maxresident)k 0.22user 5.51system 0:02.90elapsed 197%CPU (0avgtext+0avgdata 0maxresident)k 0.19user 5.44system 0:02.91elapsed 193%CPU (0avgtext+0avgdata 0maxresident)k After: 0.07user 2.34system 0:01.68elapsed 143%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.37system 0:01.68elapsed 144%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.39system 0:01.68elapsed 145%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.36system 0:01.68elapsed 144%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.42system 0:01.68elapsed 147%CPU (0avgtext+0avgdata 0maxresident)k Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1344 lines
32 KiB
C
1344 lines
32 KiB
C
/*
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* linux/drivers/block/loop.c
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*
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* Written by Theodore Ts'o, 3/29/93
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*
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* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
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* permitted under the GNU General Public License.
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*
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* DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
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* more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
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*
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* Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
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* Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
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*
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* Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
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*
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* Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
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*
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* Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
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*
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* Loadable modules and other fixes by AK, 1998
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*
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* Make real block number available to downstream transfer functions, enables
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* CBC (and relatives) mode encryption requiring unique IVs per data block.
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* Reed H. Petty, rhp@draper.net
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*
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* Maximum number of loop devices now dynamic via max_loop module parameter.
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* Russell Kroll <rkroll@exploits.org> 19990701
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*
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* Maximum number of loop devices when compiled-in now selectable by passing
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* max_loop=<1-255> to the kernel on boot.
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* Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999
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*
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* Completely rewrite request handling to be make_request_fn style and
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* non blocking, pushing work to a helper thread. Lots of fixes from
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* Al Viro too.
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* Jens Axboe <axboe@suse.de>, Nov 2000
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*
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* Support up to 256 loop devices
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* Heinz Mauelshagen <mge@sistina.com>, Feb 2002
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*
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* Support for falling back on the write file operation when the address space
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* operations prepare_write and/or commit_write are not available on the
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* backing filesystem.
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* Anton Altaparmakov, 16 Feb 2005
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*
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* Still To Fix:
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* - Advisory locking is ignored here.
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* - Should use an own CAP_* category instead of CAP_SYS_ADMIN
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*
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/major.h>
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#include <linux/wait.h>
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#include <linux/blkdev.h>
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#include <linux/blkpg.h>
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#include <linux/init.h>
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#include <linux/devfs_fs_kernel.h>
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#include <linux/smp_lock.h>
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#include <linux/swap.h>
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#include <linux/slab.h>
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#include <linux/loop.h>
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#include <linux/suspend.h>
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#include <linux/writeback.h>
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#include <linux/buffer_head.h> /* for invalidate_bdev() */
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#include <linux/completion.h>
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#include <linux/highmem.h>
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#include <linux/gfp.h>
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#include <asm/uaccess.h>
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static int max_loop = 8;
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static struct loop_device *loop_dev;
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static struct gendisk **disks;
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/*
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* Transfer functions
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*/
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static int transfer_none(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block)
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{
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char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off;
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char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off;
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if (cmd == READ)
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memcpy(loop_buf, raw_buf, size);
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else
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memcpy(raw_buf, loop_buf, size);
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kunmap_atomic(raw_buf, KM_USER0);
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kunmap_atomic(loop_buf, KM_USER1);
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cond_resched();
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return 0;
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}
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static int transfer_xor(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block)
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{
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char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off;
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char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off;
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char *in, *out, *key;
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int i, keysize;
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if (cmd == READ) {
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in = raw_buf;
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out = loop_buf;
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} else {
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in = loop_buf;
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out = raw_buf;
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}
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key = lo->lo_encrypt_key;
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keysize = lo->lo_encrypt_key_size;
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for (i = 0; i < size; i++)
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*out++ = *in++ ^ key[(i & 511) % keysize];
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kunmap_atomic(raw_buf, KM_USER0);
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kunmap_atomic(loop_buf, KM_USER1);
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cond_resched();
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return 0;
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}
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static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
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{
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if (unlikely(info->lo_encrypt_key_size <= 0))
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return -EINVAL;
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return 0;
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}
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static struct loop_func_table none_funcs = {
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.number = LO_CRYPT_NONE,
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.transfer = transfer_none,
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};
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static struct loop_func_table xor_funcs = {
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.number = LO_CRYPT_XOR,
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.transfer = transfer_xor,
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.init = xor_init
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};
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/* xfer_funcs[0] is special - its release function is never called */
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static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
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&none_funcs,
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&xor_funcs
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};
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static loff_t get_loop_size(struct loop_device *lo, struct file *file)
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{
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loff_t size, offset, loopsize;
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/* Compute loopsize in bytes */
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size = i_size_read(file->f_mapping->host);
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offset = lo->lo_offset;
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loopsize = size - offset;
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if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
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loopsize = lo->lo_sizelimit;
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/*
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* Unfortunately, if we want to do I/O on the device,
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* the number of 512-byte sectors has to fit into a sector_t.
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*/
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return loopsize >> 9;
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}
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static int
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figure_loop_size(struct loop_device *lo)
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{
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loff_t size = get_loop_size(lo, lo->lo_backing_file);
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sector_t x = (sector_t)size;
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if (unlikely((loff_t)x != size))
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return -EFBIG;
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set_capacity(disks[lo->lo_number], x);
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return 0;
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}
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static inline int
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lo_do_transfer(struct loop_device *lo, int cmd,
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struct page *rpage, unsigned roffs,
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struct page *lpage, unsigned loffs,
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int size, sector_t rblock)
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{
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if (unlikely(!lo->transfer))
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return 0;
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return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
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}
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/**
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* do_lo_send_aops - helper for writing data to a loop device
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*
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* This is the fast version for backing filesystems which implement the address
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* space operations prepare_write and commit_write.
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*/
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static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
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int bsize, loff_t pos, struct page *page)
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{
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struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
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struct address_space *mapping = file->f_mapping;
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struct address_space_operations *aops = mapping->a_ops;
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pgoff_t index;
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unsigned offset, bv_offs;
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int len, ret = 0;
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down(&mapping->host->i_sem);
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index = pos >> PAGE_CACHE_SHIFT;
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offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1);
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bv_offs = bvec->bv_offset;
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len = bvec->bv_len;
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while (len > 0) {
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sector_t IV;
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unsigned size;
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int transfer_result;
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IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
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size = PAGE_CACHE_SIZE - offset;
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if (size > len)
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size = len;
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page = grab_cache_page(mapping, index);
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if (unlikely(!page))
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goto fail;
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if (unlikely(aops->prepare_write(file, page, offset,
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offset + size)))
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goto unlock;
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transfer_result = lo_do_transfer(lo, WRITE, page, offset,
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bvec->bv_page, bv_offs, size, IV);
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if (unlikely(transfer_result)) {
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char *kaddr;
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/*
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* The transfer failed, but we still write the data to
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* keep prepare/commit calls balanced.
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*/
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printk(KERN_ERR "loop: transfer error block %llu\n",
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(unsigned long long)index);
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kaddr = kmap_atomic(page, KM_USER0);
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memset(kaddr + offset, 0, size);
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kunmap_atomic(kaddr, KM_USER0);
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}
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flush_dcache_page(page);
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if (unlikely(aops->commit_write(file, page, offset,
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offset + size)))
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goto unlock;
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if (unlikely(transfer_result))
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goto unlock;
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bv_offs += size;
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len -= size;
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offset = 0;
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index++;
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pos += size;
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unlock_page(page);
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page_cache_release(page);
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}
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out:
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up(&mapping->host->i_sem);
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return ret;
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unlock:
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unlock_page(page);
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page_cache_release(page);
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fail:
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ret = -1;
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goto out;
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}
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/**
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* __do_lo_send_write - helper for writing data to a loop device
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*
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* This helper just factors out common code between do_lo_send_direct_write()
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* and do_lo_send_write().
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*/
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static inline int __do_lo_send_write(struct file *file,
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u8 __user *buf, const int len, loff_t pos)
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{
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ssize_t bw;
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mm_segment_t old_fs = get_fs();
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set_fs(get_ds());
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bw = file->f_op->write(file, buf, len, &pos);
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set_fs(old_fs);
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if (likely(bw == len))
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return 0;
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printk(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n",
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(unsigned long long)pos, len);
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if (bw >= 0)
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bw = -EIO;
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return bw;
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}
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/**
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* do_lo_send_direct_write - helper for writing data to a loop device
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*
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* This is the fast, non-transforming version for backing filesystems which do
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* not implement the address space operations prepare_write and commit_write.
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* It uses the write file operation which should be present on all writeable
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* filesystems.
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*/
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static int do_lo_send_direct_write(struct loop_device *lo,
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struct bio_vec *bvec, int bsize, loff_t pos, struct page *page)
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{
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ssize_t bw = __do_lo_send_write(lo->lo_backing_file,
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(u8 __user *)kmap(bvec->bv_page) + bvec->bv_offset,
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bvec->bv_len, pos);
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kunmap(bvec->bv_page);
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cond_resched();
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return bw;
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}
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/**
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* do_lo_send_write - helper for writing data to a loop device
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*
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* This is the slow, transforming version for filesystems which do not
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* implement the address space operations prepare_write and commit_write. It
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* uses the write file operation which should be present on all writeable
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* filesystems.
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*
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* Using fops->write is slower than using aops->{prepare,commit}_write in the
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* transforming case because we need to double buffer the data as we cannot do
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* the transformations in place as we do not have direct access to the
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* destination pages of the backing file.
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*/
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static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
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int bsize, loff_t pos, struct page *page)
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{
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int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,
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bvec->bv_offset, bvec->bv_len, pos >> 9);
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if (likely(!ret))
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return __do_lo_send_write(lo->lo_backing_file,
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(u8 __user *)page_address(page), bvec->bv_len,
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pos);
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printk(KERN_ERR "loop: Transfer error at byte offset %llu, "
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"length %i.\n", (unsigned long long)pos, bvec->bv_len);
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if (ret > 0)
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ret = -EIO;
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return ret;
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}
|
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static int lo_send(struct loop_device *lo, struct bio *bio, int bsize,
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loff_t pos)
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{
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int (*do_lo_send)(struct loop_device *, struct bio_vec *, int, loff_t,
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struct page *page);
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struct bio_vec *bvec;
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struct page *page = NULL;
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int i, ret = 0;
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do_lo_send = do_lo_send_aops;
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if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) {
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do_lo_send = do_lo_send_direct_write;
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if (lo->transfer != transfer_none) {
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page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
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if (unlikely(!page))
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goto fail;
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kmap(page);
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do_lo_send = do_lo_send_write;
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}
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}
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bio_for_each_segment(bvec, bio, i) {
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ret = do_lo_send(lo, bvec, bsize, pos, page);
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if (ret < 0)
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break;
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pos += bvec->bv_len;
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}
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if (page) {
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kunmap(page);
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__free_page(page);
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}
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out:
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return ret;
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fail:
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printk(KERN_ERR "loop: Failed to allocate temporary page for write.\n");
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ret = -ENOMEM;
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goto out;
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}
|
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|
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struct lo_read_data {
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struct loop_device *lo;
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struct page *page;
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unsigned offset;
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int bsize;
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};
|
|
|
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static int
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lo_read_actor(read_descriptor_t *desc, struct page *page,
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unsigned long offset, unsigned long size)
|
|
{
|
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unsigned long count = desc->count;
|
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struct lo_read_data *p = desc->arg.data;
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struct loop_device *lo = p->lo;
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sector_t IV;
|
|
|
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IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
|
|
|
|
if (size > count)
|
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size = count;
|
|
|
|
if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) {
|
|
size = 0;
|
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printk(KERN_ERR "loop: transfer error block %ld\n",
|
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page->index);
|
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desc->error = -EINVAL;
|
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}
|
|
|
|
flush_dcache_page(p->page);
|
|
|
|
desc->count = count - size;
|
|
desc->written += size;
|
|
p->offset += size;
|
|
return size;
|
|
}
|
|
|
|
static int
|
|
do_lo_receive(struct loop_device *lo,
|
|
struct bio_vec *bvec, int bsize, loff_t pos)
|
|
{
|
|
struct lo_read_data cookie;
|
|
struct file *file;
|
|
int retval;
|
|
|
|
cookie.lo = lo;
|
|
cookie.page = bvec->bv_page;
|
|
cookie.offset = bvec->bv_offset;
|
|
cookie.bsize = bsize;
|
|
file = lo->lo_backing_file;
|
|
retval = file->f_op->sendfile(file, &pos, bvec->bv_len,
|
|
lo_read_actor, &cookie);
|
|
return (retval < 0)? retval: 0;
|
|
}
|
|
|
|
static int
|
|
lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
|
|
{
|
|
struct bio_vec *bvec;
|
|
int i, ret = 0;
|
|
|
|
bio_for_each_segment(bvec, bio, i) {
|
|
ret = do_lo_receive(lo, bvec, bsize, pos);
|
|
if (ret < 0)
|
|
break;
|
|
pos += bvec->bv_len;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
|
|
{
|
|
loff_t pos;
|
|
int ret;
|
|
|
|
pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset;
|
|
if (bio_rw(bio) == WRITE)
|
|
ret = lo_send(lo, bio, lo->lo_blocksize, pos);
|
|
else
|
|
ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Add bio to back of pending list
|
|
*/
|
|
static void loop_add_bio(struct loop_device *lo, struct bio *bio)
|
|
{
|
|
if (lo->lo_biotail) {
|
|
lo->lo_biotail->bi_next = bio;
|
|
lo->lo_biotail = bio;
|
|
} else
|
|
lo->lo_bio = lo->lo_biotail = bio;
|
|
}
|
|
|
|
/*
|
|
* Grab first pending buffer
|
|
*/
|
|
static struct bio *loop_get_bio(struct loop_device *lo)
|
|
{
|
|
struct bio *bio;
|
|
|
|
if ((bio = lo->lo_bio)) {
|
|
if (bio == lo->lo_biotail)
|
|
lo->lo_biotail = NULL;
|
|
lo->lo_bio = bio->bi_next;
|
|
bio->bi_next = NULL;
|
|
}
|
|
|
|
return bio;
|
|
}
|
|
|
|
static int loop_make_request(request_queue_t *q, struct bio *old_bio)
|
|
{
|
|
struct loop_device *lo = q->queuedata;
|
|
int rw = bio_rw(old_bio);
|
|
|
|
if (rw == READA)
|
|
rw = READ;
|
|
|
|
BUG_ON(!lo || (rw != READ && rw != WRITE));
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
if (lo->lo_state != Lo_bound)
|
|
goto out;
|
|
if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY)))
|
|
goto out;
|
|
lo->lo_pending++;
|
|
loop_add_bio(lo, old_bio);
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
up(&lo->lo_bh_mutex);
|
|
return 0;
|
|
|
|
out:
|
|
if (lo->lo_pending == 0)
|
|
up(&lo->lo_bh_mutex);
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
bio_io_error(old_bio, old_bio->bi_size);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* kick off io on the underlying address space
|
|
*/
|
|
static void loop_unplug(request_queue_t *q)
|
|
{
|
|
struct loop_device *lo = q->queuedata;
|
|
|
|
clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags);
|
|
blk_run_address_space(lo->lo_backing_file->f_mapping);
|
|
}
|
|
|
|
struct switch_request {
|
|
struct file *file;
|
|
struct completion wait;
|
|
};
|
|
|
|
static void do_loop_switch(struct loop_device *, struct switch_request *);
|
|
|
|
static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio)
|
|
{
|
|
if (unlikely(!bio->bi_bdev)) {
|
|
do_loop_switch(lo, bio->bi_private);
|
|
bio_put(bio);
|
|
} else {
|
|
int ret = do_bio_filebacked(lo, bio);
|
|
bio_endio(bio, bio->bi_size, ret);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 bio *bio;
|
|
|
|
daemonize("loop%d", lo->lo_number);
|
|
|
|
/*
|
|
* loop can be used in an encrypted device,
|
|
* hence, it mustn't be stopped at all
|
|
* because it could be indirectly used during suspension
|
|
*/
|
|
current->flags |= PF_NOFREEZE;
|
|
|
|
set_user_nice(current, -20);
|
|
|
|
lo->lo_state = Lo_bound;
|
|
lo->lo_pending = 1;
|
|
|
|
/*
|
|
* up sem, we are running
|
|
*/
|
|
up(&lo->lo_sem);
|
|
|
|
for (;;) {
|
|
int pending;
|
|
|
|
/*
|
|
* interruptible just to not contribute to load avg
|
|
*/
|
|
if (down_interruptible(&lo->lo_bh_mutex))
|
|
continue;
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
|
|
/*
|
|
* could be upped because of tear-down, not pending work
|
|
*/
|
|
if (unlikely(!lo->lo_pending)) {
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
break;
|
|
}
|
|
|
|
bio = loop_get_bio(lo);
|
|
lo->lo_pending--;
|
|
pending = lo->lo_pending;
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
BUG_ON(!bio);
|
|
loop_handle_bio(lo, bio);
|
|
|
|
/*
|
|
* upped both for pending work and tear-down, lo_pending
|
|
* will hit zero then
|
|
*/
|
|
if (unlikely(!pending))
|
|
break;
|
|
}
|
|
|
|
up(&lo->lo_sem);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* loop_switch performs the hard work of switching a backing store.
|
|
* First it needs to flush existing IO, it does this by sending a magic
|
|
* BIO down the pipe. The completion of this BIO does the actual switch.
|
|
*/
|
|
static int loop_switch(struct loop_device *lo, struct file *file)
|
|
{
|
|
struct switch_request w;
|
|
struct bio *bio = bio_alloc(GFP_KERNEL, 1);
|
|
if (!bio)
|
|
return -ENOMEM;
|
|
init_completion(&w.wait);
|
|
w.file = file;
|
|
bio->bi_private = &w;
|
|
bio->bi_bdev = NULL;
|
|
loop_make_request(lo->lo_queue, bio);
|
|
wait_for_completion(&w.wait);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Do the actual switch; called from the BIO completion routine
|
|
*/
|
|
static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
|
|
{
|
|
struct file *file = p->file;
|
|
struct file *old_file = lo->lo_backing_file;
|
|
struct address_space *mapping = file->f_mapping;
|
|
|
|
mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
|
|
lo->lo_backing_file = file;
|
|
lo->lo_blocksize = mapping->host->i_blksize;
|
|
lo->old_gfp_mask = mapping_gfp_mask(mapping);
|
|
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
|
complete(&p->wait);
|
|
}
|
|
|
|
|
|
/*
|
|
* loop_change_fd switched the backing store of a loopback device to
|
|
* a new file. This is useful for operating system installers to free up
|
|
* the original file and in High Availability environments to switch to
|
|
* an alternative location for the content in case of server meltdown.
|
|
* This can only work if the loop device is used read-only, and if the
|
|
* new backing store is the same size and type as the old backing store.
|
|
*/
|
|
static int loop_change_fd(struct loop_device *lo, struct file *lo_file,
|
|
struct block_device *bdev, unsigned int arg)
|
|
{
|
|
struct file *file, *old_file;
|
|
struct inode *inode;
|
|
int error;
|
|
|
|
error = -ENXIO;
|
|
if (lo->lo_state != Lo_bound)
|
|
goto out;
|
|
|
|
/* the loop device has to be read-only */
|
|
error = -EINVAL;
|
|
if (!(lo->lo_flags & LO_FLAGS_READ_ONLY))
|
|
goto out;
|
|
|
|
error = -EBADF;
|
|
file = fget(arg);
|
|
if (!file)
|
|
goto out;
|
|
|
|
inode = file->f_mapping->host;
|
|
old_file = lo->lo_backing_file;
|
|
|
|
error = -EINVAL;
|
|
|
|
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
|
|
goto out_putf;
|
|
|
|
/* new backing store needs to support loop (eg sendfile) */
|
|
if (!inode->i_fop->sendfile)
|
|
goto out_putf;
|
|
|
|
/* size of the new backing store needs to be the same */
|
|
if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
|
|
goto out_putf;
|
|
|
|
/* and ... switch */
|
|
error = loop_switch(lo, file);
|
|
if (error)
|
|
goto out_putf;
|
|
|
|
fput(old_file);
|
|
return 0;
|
|
|
|
out_putf:
|
|
fput(file);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static inline int is_loop_device(struct file *file)
|
|
{
|
|
struct inode *i = file->f_mapping->host;
|
|
|
|
return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR;
|
|
}
|
|
|
|
static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
|
|
struct block_device *bdev, unsigned int arg)
|
|
{
|
|
struct file *file, *f;
|
|
struct inode *inode;
|
|
struct address_space *mapping;
|
|
unsigned lo_blocksize;
|
|
int lo_flags = 0;
|
|
int error;
|
|
loff_t size;
|
|
|
|
/* This is safe, since we have a reference from open(). */
|
|
__module_get(THIS_MODULE);
|
|
|
|
error = -EBADF;
|
|
file = fget(arg);
|
|
if (!file)
|
|
goto out;
|
|
|
|
error = -EBUSY;
|
|
if (lo->lo_state != Lo_unbound)
|
|
goto out_putf;
|
|
|
|
/* Avoid recursion */
|
|
f = file;
|
|
while (is_loop_device(f)) {
|
|
struct loop_device *l;
|
|
|
|
if (f->f_mapping->host->i_rdev == lo_file->f_mapping->host->i_rdev)
|
|
goto out_putf;
|
|
|
|
l = f->f_mapping->host->i_bdev->bd_disk->private_data;
|
|
if (l->lo_state == Lo_unbound) {
|
|
error = -EINVAL;
|
|
goto out_putf;
|
|
}
|
|
f = l->lo_backing_file;
|
|
}
|
|
|
|
mapping = file->f_mapping;
|
|
inode = mapping->host;
|
|
|
|
if (!(file->f_mode & FMODE_WRITE))
|
|
lo_flags |= LO_FLAGS_READ_ONLY;
|
|
|
|
error = -EINVAL;
|
|
if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) {
|
|
struct address_space_operations *aops = mapping->a_ops;
|
|
/*
|
|
* If we can't read - sorry. If we only can't write - well,
|
|
* it's going to be read-only.
|
|
*/
|
|
if (!file->f_op->sendfile)
|
|
goto out_putf;
|
|
if (aops->prepare_write && aops->commit_write)
|
|
lo_flags |= LO_FLAGS_USE_AOPS;
|
|
if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write)
|
|
lo_flags |= LO_FLAGS_READ_ONLY;
|
|
|
|
lo_blocksize = inode->i_blksize;
|
|
error = 0;
|
|
} else {
|
|
goto out_putf;
|
|
}
|
|
|
|
size = get_loop_size(lo, file);
|
|
|
|
if ((loff_t)(sector_t)size != size) {
|
|
error = -EFBIG;
|
|
goto out_putf;
|
|
}
|
|
|
|
if (!(lo_file->f_mode & FMODE_WRITE))
|
|
lo_flags |= LO_FLAGS_READ_ONLY;
|
|
|
|
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
|
|
|
|
lo->lo_blocksize = lo_blocksize;
|
|
lo->lo_device = bdev;
|
|
lo->lo_flags = lo_flags;
|
|
lo->lo_backing_file = file;
|
|
lo->transfer = NULL;
|
|
lo->ioctl = NULL;
|
|
lo->lo_sizelimit = 0;
|
|
lo->old_gfp_mask = mapping_gfp_mask(mapping);
|
|
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
|
|
|
lo->lo_bio = lo->lo_biotail = NULL;
|
|
|
|
/*
|
|
* set queue make_request_fn, and add limits based on lower level
|
|
* device
|
|
*/
|
|
blk_queue_make_request(lo->lo_queue, loop_make_request);
|
|
lo->lo_queue->queuedata = lo;
|
|
lo->lo_queue->unplug_fn = loop_unplug;
|
|
|
|
set_capacity(disks[lo->lo_number], size);
|
|
bd_set_size(bdev, size << 9);
|
|
|
|
set_blocksize(bdev, lo_blocksize);
|
|
|
|
kernel_thread(loop_thread, lo, CLONE_KERNEL);
|
|
down(&lo->lo_sem);
|
|
return 0;
|
|
|
|
out_putf:
|
|
fput(file);
|
|
out:
|
|
/* This is safe: open() is still holding a reference. */
|
|
module_put(THIS_MODULE);
|
|
return error;
|
|
}
|
|
|
|
static int
|
|
loop_release_xfer(struct loop_device *lo)
|
|
{
|
|
int err = 0;
|
|
struct loop_func_table *xfer = lo->lo_encryption;
|
|
|
|
if (xfer) {
|
|
if (xfer->release)
|
|
err = xfer->release(lo);
|
|
lo->transfer = NULL;
|
|
lo->lo_encryption = NULL;
|
|
module_put(xfer->owner);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
|
|
const struct loop_info64 *i)
|
|
{
|
|
int err = 0;
|
|
|
|
if (xfer) {
|
|
struct module *owner = xfer->owner;
|
|
|
|
if (!try_module_get(owner))
|
|
return -EINVAL;
|
|
if (xfer->init)
|
|
err = xfer->init(lo, i);
|
|
if (err)
|
|
module_put(owner);
|
|
else
|
|
lo->lo_encryption = xfer;
|
|
}
|
|
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;
|
|
lo->lo_pending--;
|
|
if (!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 = NULL;
|
|
lo->lo_encryption = NULL;
|
|
lo->lo_offset = 0;
|
|
lo->lo_sizelimit = 0;
|
|
lo->lo_encrypt_key_size = 0;
|
|
lo->lo_flags = 0;
|
|
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);
|
|
bd_set_size(bdev, 0);
|
|
mapping_set_gfp_mask(filp->f_mapping, gfp);
|
|
lo->lo_state = Lo_unbound;
|
|
fput(filp);
|
|
/* This is safe: open() is still holding a reference. */
|
|
module_put(THIS_MODULE);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
|
|
{
|
|
int err;
|
|
struct loop_func_table *xfer;
|
|
|
|
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 ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
|
|
return -EINVAL;
|
|
|
|
err = loop_release_xfer(lo);
|
|
if (err)
|
|
return err;
|
|
|
|
if (info->lo_encrypt_type) {
|
|
unsigned int type = info->lo_encrypt_type;
|
|
|
|
if (type >= MAX_LO_CRYPT)
|
|
return -EINVAL;
|
|
xfer = xfer_funcs[type];
|
|
if (xfer == NULL)
|
|
return -EINVAL;
|
|
} else
|
|
xfer = NULL;
|
|
|
|
err = loop_init_xfer(lo, xfer, info);
|
|
if (err)
|
|
return err;
|
|
|
|
if (lo->lo_offset != info->lo_offset ||
|
|
lo->lo_sizelimit != info->lo_sizelimit) {
|
|
lo->lo_offset = info->lo_offset;
|
|
lo->lo_sizelimit = info->lo_sizelimit;
|
|
if (figure_loop_size(lo))
|
|
return -EFBIG;
|
|
}
|
|
|
|
memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
|
|
memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
|
|
lo->lo_file_name[LO_NAME_SIZE-1] = 0;
|
|
lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
|
|
|
|
if (!xfer)
|
|
xfer = &none_funcs;
|
|
lo->transfer = xfer->transfer;
|
|
lo->ioctl = xfer->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;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
loop_get_status(struct loop_device *lo, struct loop_info64 *info)
|
|
{
|
|
struct file *file = lo->lo_backing_file;
|
|
struct kstat stat;
|
|
int error;
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
return -ENXIO;
|
|
error = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat);
|
|
if (error)
|
|
return error;
|
|
memset(info, 0, sizeof(*info));
|
|
info->lo_number = lo->lo_number;
|
|
info->lo_device = huge_encode_dev(stat.dev);
|
|
info->lo_inode = stat.ino;
|
|
info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev);
|
|
info->lo_offset = lo->lo_offset;
|
|
info->lo_sizelimit = lo->lo_sizelimit;
|
|
info->lo_flags = lo->lo_flags;
|
|
memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
|
|
memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
|
|
info->lo_encrypt_type =
|
|
lo->lo_encryption ? lo->lo_encryption->number : 0;
|
|
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 0;
|
|
}
|
|
|
|
static void
|
|
loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64)
|
|
{
|
|
memset(info64, 0, sizeof(*info64));
|
|
info64->lo_number = info->lo_number;
|
|
info64->lo_device = info->lo_device;
|
|
info64->lo_inode = info->lo_inode;
|
|
info64->lo_rdevice = info->lo_rdevice;
|
|
info64->lo_offset = info->lo_offset;
|
|
info64->lo_sizelimit = 0;
|
|
info64->lo_encrypt_type = info->lo_encrypt_type;
|
|
info64->lo_encrypt_key_size = info->lo_encrypt_key_size;
|
|
info64->lo_flags = info->lo_flags;
|
|
info64->lo_init[0] = info->lo_init[0];
|
|
info64->lo_init[1] = info->lo_init[1];
|
|
if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
|
|
memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
|
|
else
|
|
memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
|
|
memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
|
|
}
|
|
|
|
static int
|
|
loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
|
|
{
|
|
memset(info, 0, sizeof(*info));
|
|
info->lo_number = info64->lo_number;
|
|
info->lo_device = info64->lo_device;
|
|
info->lo_inode = info64->lo_inode;
|
|
info->lo_rdevice = info64->lo_rdevice;
|
|
info->lo_offset = info64->lo_offset;
|
|
info->lo_encrypt_type = info64->lo_encrypt_type;
|
|
info->lo_encrypt_key_size = info64->lo_encrypt_key_size;
|
|
info->lo_flags = info64->lo_flags;
|
|
info->lo_init[0] = info64->lo_init[0];
|
|
info->lo_init[1] = info64->lo_init[1];
|
|
if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
|
|
memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
|
|
else
|
|
memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
|
|
memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
|
|
|
|
/* error in case values were truncated */
|
|
if (info->lo_device != info64->lo_device ||
|
|
info->lo_rdevice != info64->lo_rdevice ||
|
|
info->lo_inode != info64->lo_inode ||
|
|
info->lo_offset != info64->lo_offset)
|
|
return -EOVERFLOW;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg)
|
|
{
|
|
struct loop_info info;
|
|
struct loop_info64 info64;
|
|
|
|
if (copy_from_user(&info, arg, sizeof (struct loop_info)))
|
|
return -EFAULT;
|
|
loop_info64_from_old(&info, &info64);
|
|
return loop_set_status(lo, &info64);
|
|
}
|
|
|
|
static int
|
|
loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg)
|
|
{
|
|
struct loop_info64 info64;
|
|
|
|
if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
|
|
return -EFAULT;
|
|
return loop_set_status(lo, &info64);
|
|
}
|
|
|
|
static int
|
|
loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) {
|
|
struct loop_info info;
|
|
struct loop_info64 info64;
|
|
int err = 0;
|
|
|
|
if (!arg)
|
|
err = -EINVAL;
|
|
if (!err)
|
|
err = loop_get_status(lo, &info64);
|
|
if (!err)
|
|
err = loop_info64_to_old(&info64, &info);
|
|
if (!err && copy_to_user(arg, &info, sizeof(info)))
|
|
err = -EFAULT;
|
|
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
|
|
struct loop_info64 info64;
|
|
int err = 0;
|
|
|
|
if (!arg)
|
|
err = -EINVAL;
|
|
if (!err)
|
|
err = loop_get_status(lo, &info64);
|
|
if (!err && copy_to_user(arg, &info64, sizeof(info64)))
|
|
err = -EFAULT;
|
|
|
|
return err;
|
|
}
|
|
|
|
static int lo_ioctl(struct inode * inode, struct file * file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
|
|
int err;
|
|
|
|
down(&lo->lo_ctl_mutex);
|
|
switch (cmd) {
|
|
case LOOP_SET_FD:
|
|
err = loop_set_fd(lo, file, inode->i_bdev, arg);
|
|
break;
|
|
case LOOP_CHANGE_FD:
|
|
err = loop_change_fd(lo, file, inode->i_bdev, arg);
|
|
break;
|
|
case LOOP_CLR_FD:
|
|
err = loop_clr_fd(lo, inode->i_bdev);
|
|
break;
|
|
case LOOP_SET_STATUS:
|
|
err = loop_set_status_old(lo, (struct loop_info __user *) arg);
|
|
break;
|
|
case LOOP_GET_STATUS:
|
|
err = loop_get_status_old(lo, (struct loop_info __user *) arg);
|
|
break;
|
|
case LOOP_SET_STATUS64:
|
|
err = loop_set_status64(lo, (struct loop_info64 __user *) arg);
|
|
break;
|
|
case LOOP_GET_STATUS64:
|
|
err = loop_get_status64(lo, (struct loop_info64 __user *) 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 = inode->i_bdev->bd_disk->private_data;
|
|
|
|
down(&lo->lo_ctl_mutex);
|
|
lo->lo_refcnt++;
|
|
up(&lo->lo_ctl_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int lo_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
|
|
|
|
down(&lo->lo_ctl_mutex);
|
|
--lo->lo_refcnt;
|
|
up(&lo->lo_ctl_mutex);
|
|
|
|
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_param(max_loop, int, 0);
|
|
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
|
|
|
|
int loop_register_transfer(struct loop_func_table *funcs)
|
|
{
|
|
unsigned int n = funcs->number;
|
|
|
|
if (n >= MAX_LO_CRYPT || xfer_funcs[n])
|
|
return -EINVAL;
|
|
xfer_funcs[n] = funcs;
|
|
return 0;
|
|
}
|
|
|
|
int loop_unregister_transfer(int number)
|
|
{
|
|
unsigned int n = number;
|
|
struct loop_device *lo;
|
|
struct loop_func_table *xfer;
|
|
|
|
if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
|
|
return -EINVAL;
|
|
|
|
xfer_funcs[n] = NULL;
|
|
|
|
for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
|
|
down(&lo->lo_ctl_mutex);
|
|
|
|
if (lo->lo_encryption == xfer)
|
|
loop_release_xfer(lo);
|
|
|
|
up(&lo->lo_ctl_mutex);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(loop_register_transfer);
|
|
EXPORT_SYMBOL(loop_unregister_transfer);
|
|
|
|
static int __init loop_init(void)
|
|
{
|
|
int i;
|
|
|
|
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;
|
|
}
|
|
|
|
if (register_blkdev(LOOP_MAJOR, "loop"))
|
|
return -EIO;
|
|
|
|
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));
|
|
|
|
disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL);
|
|
if (!disks)
|
|
goto out_mem2;
|
|
|
|
for (i = 0; i < max_loop; i++) {
|
|
disks[i] = alloc_disk(1);
|
|
if (!disks[i])
|
|
goto out_mem3;
|
|
}
|
|
|
|
devfs_mk_dir("loop");
|
|
|
|
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;
|
|
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);
|
|
disk->major = LOOP_MAJOR;
|
|
disk->first_minor = i;
|
|
disk->fops = &lo_fops;
|
|
sprintf(disk->disk_name, "loop%d", i);
|
|
sprintf(disk->devfs_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);
|
|
return 0;
|
|
|
|
out_mem4:
|
|
while (i--)
|
|
blk_put_queue(loop_dev[i].lo_queue);
|
|
devfs_remove("loop");
|
|
i = max_loop;
|
|
out_mem3:
|
|
while (i--)
|
|
put_disk(disks[i]);
|
|
kfree(disks);
|
|
out_mem2:
|
|
kfree(loop_dev);
|
|
out_mem1:
|
|
unregister_blkdev(LOOP_MAJOR, "loop");
|
|
printk(KERN_ERR "loop: ran out of memory\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void loop_exit(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < max_loop; i++) {
|
|
del_gendisk(disks[i]);
|
|
blk_put_queue(loop_dev[i].lo_queue);
|
|
put_disk(disks[i]);
|
|
}
|
|
devfs_remove("loop");
|
|
if (unregister_blkdev(LOOP_MAJOR, "loop"))
|
|
printk(KERN_WARNING "loop: cannot unregister blkdev\n");
|
|
|
|
kfree(disks);
|
|
kfree(loop_dev);
|
|
}
|
|
|
|
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
|