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![Colin Ian King](/assets/img/avatar_default.png)
The pointer node is being initialized with a value that is never read, it is being re-assigned the same value a little futher on. Remove the redundant initialization. Cleans up clang scan warning: drivers/block/loop.c:823:19: warning: Value stored to 'node' during its initialization is never read [deadcode.DeadStores] Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Link: https://lore.kernel.org/r/20220113001432.1331871-1-colin.i.king@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2292 lines
58 KiB
C
2292 lines
58 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 write_begin is not available on the 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/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/pagemap.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/swap.h>
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#include <linux/slab.h>
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#include <linux/compat.h>
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#include <linux/suspend.h>
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#include <linux/freezer.h>
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#include <linux/mutex.h>
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#include <linux/writeback.h>
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#include <linux/completion.h>
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#include <linux/highmem.h>
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#include <linux/splice.h>
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#include <linux/sysfs.h>
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#include <linux/miscdevice.h>
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#include <linux/falloc.h>
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#include <linux/uio.h>
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#include <linux/ioprio.h>
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#include <linux/blk-cgroup.h>
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#include <linux/sched/mm.h>
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#include "loop.h"
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#include <linux/uaccess.h>
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#define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ)
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static DEFINE_IDR(loop_index_idr);
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static DEFINE_MUTEX(loop_ctl_mutex);
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static DEFINE_MUTEX(loop_validate_mutex);
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/**
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* loop_global_lock_killable() - take locks for safe loop_validate_file() test
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*
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* @lo: struct loop_device
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* @global: true if @lo is about to bind another "struct loop_device", false otherwise
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*
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* Returns 0 on success, -EINTR otherwise.
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*
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* Since loop_validate_file() traverses on other "struct loop_device" if
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* is_loop_device() is true, we need a global lock for serializing concurrent
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* loop_configure()/loop_change_fd()/__loop_clr_fd() calls.
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*/
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static int loop_global_lock_killable(struct loop_device *lo, bool global)
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{
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int err;
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if (global) {
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err = mutex_lock_killable(&loop_validate_mutex);
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if (err)
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return err;
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}
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err = mutex_lock_killable(&lo->lo_mutex);
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if (err && global)
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mutex_unlock(&loop_validate_mutex);
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return err;
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}
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/**
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* loop_global_unlock() - release locks taken by loop_global_lock_killable()
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*
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* @lo: struct loop_device
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* @global: true if @lo was about to bind another "struct loop_device", false otherwise
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*/
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static void loop_global_unlock(struct loop_device *lo, bool global)
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{
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mutex_unlock(&lo->lo_mutex);
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if (global)
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mutex_unlock(&loop_validate_mutex);
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}
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static int max_part;
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static int part_shift;
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static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
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{
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loff_t loopsize;
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/* Compute loopsize in bytes */
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loopsize = i_size_read(file->f_mapping->host);
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if (offset > 0)
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loopsize -= offset;
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/* offset is beyond i_size, weird but possible */
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if (loopsize < 0)
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return 0;
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if (sizelimit > 0 && sizelimit < loopsize)
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loopsize = 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 loff_t get_loop_size(struct loop_device *lo, struct file *file)
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{
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return get_size(lo->lo_offset, lo->lo_sizelimit, file);
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}
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static void __loop_update_dio(struct loop_device *lo, bool dio)
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{
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struct file *file = lo->lo_backing_file;
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struct address_space *mapping = file->f_mapping;
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struct inode *inode = mapping->host;
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unsigned short sb_bsize = 0;
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unsigned dio_align = 0;
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bool use_dio;
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if (inode->i_sb->s_bdev) {
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sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
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dio_align = sb_bsize - 1;
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}
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/*
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* We support direct I/O only if lo_offset is aligned with the
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* logical I/O size of backing device, and the logical block
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* size of loop is bigger than the backing device's.
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*
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* TODO: the above condition may be loosed in the future, and
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* direct I/O may be switched runtime at that time because most
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* of requests in sane applications should be PAGE_SIZE aligned
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*/
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if (dio) {
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if (queue_logical_block_size(lo->lo_queue) >= sb_bsize &&
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!(lo->lo_offset & dio_align) &&
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mapping->a_ops->direct_IO)
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use_dio = true;
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else
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use_dio = false;
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} else {
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use_dio = false;
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}
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if (lo->use_dio == use_dio)
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return;
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/* flush dirty pages before changing direct IO */
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vfs_fsync(file, 0);
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/*
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* The flag of LO_FLAGS_DIRECT_IO is handled similarly with
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* LO_FLAGS_READ_ONLY, both are set from kernel, and losetup
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* will get updated by ioctl(LOOP_GET_STATUS)
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*/
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if (lo->lo_state == Lo_bound)
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blk_mq_freeze_queue(lo->lo_queue);
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lo->use_dio = use_dio;
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if (use_dio) {
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blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue);
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lo->lo_flags |= LO_FLAGS_DIRECT_IO;
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} else {
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blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue);
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lo->lo_flags &= ~LO_FLAGS_DIRECT_IO;
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}
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if (lo->lo_state == Lo_bound)
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blk_mq_unfreeze_queue(lo->lo_queue);
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}
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/**
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* loop_set_size() - sets device size and notifies userspace
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* @lo: struct loop_device to set the size for
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* @size: new size of the loop device
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*
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* Callers must validate that the size passed into this function fits into
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* a sector_t, eg using loop_validate_size()
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*/
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static void loop_set_size(struct loop_device *lo, loff_t size)
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{
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if (!set_capacity_and_notify(lo->lo_disk, size))
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kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE);
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}
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static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
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{
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struct iov_iter i;
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ssize_t bw;
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iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len);
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file_start_write(file);
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bw = vfs_iter_write(file, &i, ppos, 0);
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file_end_write(file);
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if (likely(bw == bvec->bv_len))
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return 0;
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printk_ratelimited(KERN_ERR
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"loop: Write error at byte offset %llu, length %i.\n",
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(unsigned long long)*ppos, bvec->bv_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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static int lo_write_simple(struct loop_device *lo, struct request *rq,
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loff_t pos)
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{
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struct bio_vec bvec;
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struct req_iterator iter;
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int ret = 0;
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rq_for_each_segment(bvec, rq, iter) {
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ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
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if (ret < 0)
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break;
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cond_resched();
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}
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return ret;
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}
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static int lo_read_simple(struct loop_device *lo, struct request *rq,
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loff_t pos)
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{
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struct bio_vec bvec;
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struct req_iterator iter;
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struct iov_iter i;
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ssize_t len;
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rq_for_each_segment(bvec, rq, iter) {
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iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len);
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len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
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if (len < 0)
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return len;
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flush_dcache_page(bvec.bv_page);
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if (len != bvec.bv_len) {
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struct bio *bio;
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__rq_for_each_bio(bio, rq)
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zero_fill_bio(bio);
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break;
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}
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cond_resched();
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}
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return 0;
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}
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static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
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int mode)
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{
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/*
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* We use fallocate to manipulate the space mappings used by the image
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* a.k.a. discard/zerorange.
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*/
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struct file *file = lo->lo_backing_file;
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struct request_queue *q = lo->lo_queue;
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int ret;
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mode |= FALLOC_FL_KEEP_SIZE;
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if (!blk_queue_discard(q)) {
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ret = -EOPNOTSUPP;
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goto out;
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}
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ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
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if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
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ret = -EIO;
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out:
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return ret;
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}
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static int lo_req_flush(struct loop_device *lo, struct request *rq)
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{
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struct file *file = lo->lo_backing_file;
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int ret = vfs_fsync(file, 0);
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if (unlikely(ret && ret != -EINVAL))
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ret = -EIO;
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return ret;
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}
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static void lo_complete_rq(struct request *rq)
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{
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struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
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blk_status_t ret = BLK_STS_OK;
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if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) ||
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req_op(rq) != REQ_OP_READ) {
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if (cmd->ret < 0)
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ret = errno_to_blk_status(cmd->ret);
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goto end_io;
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}
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/*
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* Short READ - if we got some data, advance our request and
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* retry it. If we got no data, end the rest with EIO.
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*/
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if (cmd->ret) {
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blk_update_request(rq, BLK_STS_OK, cmd->ret);
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cmd->ret = 0;
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blk_mq_requeue_request(rq, true);
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} else {
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if (cmd->use_aio) {
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struct bio *bio = rq->bio;
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while (bio) {
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zero_fill_bio(bio);
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bio = bio->bi_next;
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}
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}
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ret = BLK_STS_IOERR;
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end_io:
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blk_mq_end_request(rq, ret);
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}
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}
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static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
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{
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struct request *rq = blk_mq_rq_from_pdu(cmd);
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if (!atomic_dec_and_test(&cmd->ref))
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return;
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kfree(cmd->bvec);
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cmd->bvec = NULL;
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if (likely(!blk_should_fake_timeout(rq->q)))
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blk_mq_complete_request(rq);
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}
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static void lo_rw_aio_complete(struct kiocb *iocb, long ret)
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{
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struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb);
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cmd->ret = ret;
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lo_rw_aio_do_completion(cmd);
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}
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static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
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loff_t pos, bool rw)
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{
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struct iov_iter iter;
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struct req_iterator rq_iter;
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struct bio_vec *bvec;
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struct request *rq = blk_mq_rq_from_pdu(cmd);
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struct bio *bio = rq->bio;
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struct file *file = lo->lo_backing_file;
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struct bio_vec tmp;
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unsigned int offset;
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int nr_bvec = 0;
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int ret;
|
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|
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rq_for_each_bvec(tmp, rq, rq_iter)
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nr_bvec++;
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|
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if (rq->bio != rq->biotail) {
|
|
|
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bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
|
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GFP_NOIO);
|
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if (!bvec)
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return -EIO;
|
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cmd->bvec = bvec;
|
|
|
|
/*
|
|
* The bios of the request may be started from the middle of
|
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* the 'bvec' because of bio splitting, so we can't directly
|
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* copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec
|
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* API will take care of all details for us.
|
|
*/
|
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rq_for_each_bvec(tmp, rq, rq_iter) {
|
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*bvec = tmp;
|
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bvec++;
|
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}
|
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bvec = cmd->bvec;
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offset = 0;
|
|
} else {
|
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/*
|
|
* Same here, this bio may be started from the middle of the
|
|
* 'bvec' because of bio splitting, so offset from the bvec
|
|
* must be passed to iov iterator
|
|
*/
|
|
offset = bio->bi_iter.bi_bvec_done;
|
|
bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
|
|
}
|
|
atomic_set(&cmd->ref, 2);
|
|
|
|
iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq));
|
|
iter.iov_offset = offset;
|
|
|
|
cmd->iocb.ki_pos = pos;
|
|
cmd->iocb.ki_filp = file;
|
|
cmd->iocb.ki_complete = lo_rw_aio_complete;
|
|
cmd->iocb.ki_flags = IOCB_DIRECT;
|
|
cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
|
|
|
|
if (rw == WRITE)
|
|
ret = call_write_iter(file, &cmd->iocb, &iter);
|
|
else
|
|
ret = call_read_iter(file, &cmd->iocb, &iter);
|
|
|
|
lo_rw_aio_do_completion(cmd);
|
|
|
|
if (ret != -EIOCBQUEUED)
|
|
lo_rw_aio_complete(&cmd->iocb, ret);
|
|
return 0;
|
|
}
|
|
|
|
static int do_req_filebacked(struct loop_device *lo, struct request *rq)
|
|
{
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
|
|
loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
|
|
|
|
/*
|
|
* lo_write_simple and lo_read_simple should have been covered
|
|
* by io submit style function like lo_rw_aio(), one blocker
|
|
* is that lo_read_simple() need to call flush_dcache_page after
|
|
* the page is written from kernel, and it isn't easy to handle
|
|
* this in io submit style function which submits all segments
|
|
* of the req at one time. And direct read IO doesn't need to
|
|
* run flush_dcache_page().
|
|
*/
|
|
switch (req_op(rq)) {
|
|
case REQ_OP_FLUSH:
|
|
return lo_req_flush(lo, rq);
|
|
case REQ_OP_WRITE_ZEROES:
|
|
/*
|
|
* If the caller doesn't want deallocation, call zeroout to
|
|
* write zeroes the range. Otherwise, punch them out.
|
|
*/
|
|
return lo_fallocate(lo, rq, pos,
|
|
(rq->cmd_flags & REQ_NOUNMAP) ?
|
|
FALLOC_FL_ZERO_RANGE :
|
|
FALLOC_FL_PUNCH_HOLE);
|
|
case REQ_OP_DISCARD:
|
|
return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
|
|
case REQ_OP_WRITE:
|
|
if (cmd->use_aio)
|
|
return lo_rw_aio(lo, cmd, pos, WRITE);
|
|
else
|
|
return lo_write_simple(lo, rq, pos);
|
|
case REQ_OP_READ:
|
|
if (cmd->use_aio)
|
|
return lo_rw_aio(lo, cmd, pos, READ);
|
|
else
|
|
return lo_read_simple(lo, rq, pos);
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
return -EIO;
|
|
}
|
|
}
|
|
|
|
static inline void loop_update_dio(struct loop_device *lo)
|
|
{
|
|
__loop_update_dio(lo, (lo->lo_backing_file->f_flags & O_DIRECT) |
|
|
lo->use_dio);
|
|
}
|
|
|
|
static void loop_reread_partitions(struct loop_device *lo)
|
|
{
|
|
int rc;
|
|
|
|
mutex_lock(&lo->lo_disk->open_mutex);
|
|
rc = bdev_disk_changed(lo->lo_disk, false);
|
|
mutex_unlock(&lo->lo_disk->open_mutex);
|
|
if (rc)
|
|
pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
|
|
__func__, lo->lo_number, lo->lo_file_name, rc);
|
|
}
|
|
|
|
static inline int is_loop_device(struct file *file)
|
|
{
|
|
struct inode *i = file->f_mapping->host;
|
|
|
|
return i && S_ISBLK(i->i_mode) && imajor(i) == LOOP_MAJOR;
|
|
}
|
|
|
|
static int loop_validate_file(struct file *file, struct block_device *bdev)
|
|
{
|
|
struct inode *inode = file->f_mapping->host;
|
|
struct file *f = file;
|
|
|
|
/* Avoid recursion */
|
|
while (is_loop_device(f)) {
|
|
struct loop_device *l;
|
|
|
|
lockdep_assert_held(&loop_validate_mutex);
|
|
if (f->f_mapping->host->i_rdev == bdev->bd_dev)
|
|
return -EBADF;
|
|
|
|
l = I_BDEV(f->f_mapping->host)->bd_disk->private_data;
|
|
if (l->lo_state != Lo_bound)
|
|
return -EINVAL;
|
|
/* Order wrt setting lo->lo_backing_file in loop_configure(). */
|
|
rmb();
|
|
f = l->lo_backing_file;
|
|
}
|
|
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
|
|
return -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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 block_device *bdev,
|
|
unsigned int arg)
|
|
{
|
|
struct file *file = fget(arg);
|
|
struct file *old_file;
|
|
int error;
|
|
bool partscan;
|
|
bool is_loop;
|
|
|
|
if (!file)
|
|
return -EBADF;
|
|
is_loop = is_loop_device(file);
|
|
error = loop_global_lock_killable(lo, is_loop);
|
|
if (error)
|
|
goto out_putf;
|
|
error = -ENXIO;
|
|
if (lo->lo_state != Lo_bound)
|
|
goto out_err;
|
|
|
|
/* the loop device has to be read-only */
|
|
error = -EINVAL;
|
|
if (!(lo->lo_flags & LO_FLAGS_READ_ONLY))
|
|
goto out_err;
|
|
|
|
error = loop_validate_file(file, bdev);
|
|
if (error)
|
|
goto out_err;
|
|
|
|
old_file = lo->lo_backing_file;
|
|
|
|
error = -EINVAL;
|
|
|
|
/* 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_err;
|
|
|
|
/* and ... switch */
|
|
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
|
|
lo->lo_backing_file = file;
|
|
lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping);
|
|
mapping_set_gfp_mask(file->f_mapping,
|
|
lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
|
loop_update_dio(lo);
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
|
|
loop_global_unlock(lo, is_loop);
|
|
|
|
/*
|
|
* Flush loop_validate_file() before fput(), for l->lo_backing_file
|
|
* might be pointing at old_file which might be the last reference.
|
|
*/
|
|
if (!is_loop) {
|
|
mutex_lock(&loop_validate_mutex);
|
|
mutex_unlock(&loop_validate_mutex);
|
|
}
|
|
/*
|
|
* We must drop file reference outside of lo_mutex as dropping
|
|
* the file ref can take open_mutex which creates circular locking
|
|
* dependency.
|
|
*/
|
|
fput(old_file);
|
|
if (partscan)
|
|
loop_reread_partitions(lo);
|
|
return 0;
|
|
|
|
out_err:
|
|
loop_global_unlock(lo, is_loop);
|
|
out_putf:
|
|
fput(file);
|
|
return error;
|
|
}
|
|
|
|
/* loop sysfs attributes */
|
|
|
|
static ssize_t loop_attr_show(struct device *dev, char *page,
|
|
ssize_t (*callback)(struct loop_device *, char *))
|
|
{
|
|
struct gendisk *disk = dev_to_disk(dev);
|
|
struct loop_device *lo = disk->private_data;
|
|
|
|
return callback(lo, page);
|
|
}
|
|
|
|
#define LOOP_ATTR_RO(_name) \
|
|
static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \
|
|
static ssize_t loop_attr_do_show_##_name(struct device *d, \
|
|
struct device_attribute *attr, char *b) \
|
|
{ \
|
|
return loop_attr_show(d, b, loop_attr_##_name##_show); \
|
|
} \
|
|
static struct device_attribute loop_attr_##_name = \
|
|
__ATTR(_name, 0444, loop_attr_do_show_##_name, NULL);
|
|
|
|
static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf)
|
|
{
|
|
ssize_t ret;
|
|
char *p = NULL;
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
if (lo->lo_backing_file)
|
|
p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1);
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
if (IS_ERR_OR_NULL(p))
|
|
ret = PTR_ERR(p);
|
|
else {
|
|
ret = strlen(p);
|
|
memmove(buf, p, ret);
|
|
buf[ret++] = '\n';
|
|
buf[ret] = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf)
|
|
{
|
|
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset);
|
|
}
|
|
|
|
static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf)
|
|
{
|
|
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
|
|
}
|
|
|
|
static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf)
|
|
{
|
|
int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR);
|
|
|
|
return sprintf(buf, "%s\n", autoclear ? "1" : "0");
|
|
}
|
|
|
|
static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf)
|
|
{
|
|
int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN);
|
|
|
|
return sprintf(buf, "%s\n", partscan ? "1" : "0");
|
|
}
|
|
|
|
static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf)
|
|
{
|
|
int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO);
|
|
|
|
return sprintf(buf, "%s\n", dio ? "1" : "0");
|
|
}
|
|
|
|
LOOP_ATTR_RO(backing_file);
|
|
LOOP_ATTR_RO(offset);
|
|
LOOP_ATTR_RO(sizelimit);
|
|
LOOP_ATTR_RO(autoclear);
|
|
LOOP_ATTR_RO(partscan);
|
|
LOOP_ATTR_RO(dio);
|
|
|
|
static struct attribute *loop_attrs[] = {
|
|
&loop_attr_backing_file.attr,
|
|
&loop_attr_offset.attr,
|
|
&loop_attr_sizelimit.attr,
|
|
&loop_attr_autoclear.attr,
|
|
&loop_attr_partscan.attr,
|
|
&loop_attr_dio.attr,
|
|
NULL,
|
|
};
|
|
|
|
static struct attribute_group loop_attribute_group = {
|
|
.name = "loop",
|
|
.attrs= loop_attrs,
|
|
};
|
|
|
|
static void loop_sysfs_init(struct loop_device *lo)
|
|
{
|
|
lo->sysfs_inited = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
|
|
&loop_attribute_group);
|
|
}
|
|
|
|
static void loop_sysfs_exit(struct loop_device *lo)
|
|
{
|
|
if (lo->sysfs_inited)
|
|
sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
|
|
&loop_attribute_group);
|
|
}
|
|
|
|
static void loop_config_discard(struct loop_device *lo)
|
|
{
|
|
struct file *file = lo->lo_backing_file;
|
|
struct inode *inode = file->f_mapping->host;
|
|
struct request_queue *q = lo->lo_queue;
|
|
u32 granularity, max_discard_sectors;
|
|
|
|
/*
|
|
* If the backing device is a block device, mirror its zeroing
|
|
* capability. Set the discard sectors to the block device's zeroing
|
|
* capabilities because loop discards result in blkdev_issue_zeroout(),
|
|
* not blkdev_issue_discard(). This maintains consistent behavior with
|
|
* file-backed loop devices: discarded regions read back as zero.
|
|
*/
|
|
if (S_ISBLK(inode->i_mode)) {
|
|
struct request_queue *backingq = bdev_get_queue(I_BDEV(inode));
|
|
|
|
max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
|
|
granularity = backingq->limits.discard_granularity ?:
|
|
queue_physical_block_size(backingq);
|
|
|
|
/*
|
|
* We use punch hole to reclaim the free space used by the
|
|
* image a.k.a. discard.
|
|
*/
|
|
} else if (!file->f_op->fallocate) {
|
|
max_discard_sectors = 0;
|
|
granularity = 0;
|
|
|
|
} else {
|
|
max_discard_sectors = UINT_MAX >> 9;
|
|
granularity = inode->i_sb->s_blocksize;
|
|
}
|
|
|
|
if (max_discard_sectors) {
|
|
q->limits.discard_granularity = granularity;
|
|
blk_queue_max_discard_sectors(q, max_discard_sectors);
|
|
blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
|
|
blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
|
|
} else {
|
|
q->limits.discard_granularity = 0;
|
|
blk_queue_max_discard_sectors(q, 0);
|
|
blk_queue_max_write_zeroes_sectors(q, 0);
|
|
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
|
|
}
|
|
q->limits.discard_alignment = 0;
|
|
}
|
|
|
|
struct loop_worker {
|
|
struct rb_node rb_node;
|
|
struct work_struct work;
|
|
struct list_head cmd_list;
|
|
struct list_head idle_list;
|
|
struct loop_device *lo;
|
|
struct cgroup_subsys_state *blkcg_css;
|
|
unsigned long last_ran_at;
|
|
};
|
|
|
|
static void loop_workfn(struct work_struct *work);
|
|
static void loop_rootcg_workfn(struct work_struct *work);
|
|
static void loop_free_idle_workers(struct timer_list *timer);
|
|
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
static inline int queue_on_root_worker(struct cgroup_subsys_state *css)
|
|
{
|
|
return !css || css == blkcg_root_css;
|
|
}
|
|
#else
|
|
static inline int queue_on_root_worker(struct cgroup_subsys_state *css)
|
|
{
|
|
return !css;
|
|
}
|
|
#endif
|
|
|
|
static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd)
|
|
{
|
|
struct rb_node **node, *parent = NULL;
|
|
struct loop_worker *cur_worker, *worker = NULL;
|
|
struct work_struct *work;
|
|
struct list_head *cmd_list;
|
|
|
|
spin_lock_irq(&lo->lo_work_lock);
|
|
|
|
if (queue_on_root_worker(cmd->blkcg_css))
|
|
goto queue_work;
|
|
|
|
node = &lo->worker_tree.rb_node;
|
|
|
|
while (*node) {
|
|
parent = *node;
|
|
cur_worker = container_of(*node, struct loop_worker, rb_node);
|
|
if (cur_worker->blkcg_css == cmd->blkcg_css) {
|
|
worker = cur_worker;
|
|
break;
|
|
} else if ((long)cur_worker->blkcg_css < (long)cmd->blkcg_css) {
|
|
node = &(*node)->rb_left;
|
|
} else {
|
|
node = &(*node)->rb_right;
|
|
}
|
|
}
|
|
if (worker)
|
|
goto queue_work;
|
|
|
|
worker = kzalloc(sizeof(struct loop_worker), GFP_NOWAIT | __GFP_NOWARN);
|
|
/*
|
|
* In the event we cannot allocate a worker, just queue on the
|
|
* rootcg worker and issue the I/O as the rootcg
|
|
*/
|
|
if (!worker) {
|
|
cmd->blkcg_css = NULL;
|
|
if (cmd->memcg_css)
|
|
css_put(cmd->memcg_css);
|
|
cmd->memcg_css = NULL;
|
|
goto queue_work;
|
|
}
|
|
|
|
worker->blkcg_css = cmd->blkcg_css;
|
|
css_get(worker->blkcg_css);
|
|
INIT_WORK(&worker->work, loop_workfn);
|
|
INIT_LIST_HEAD(&worker->cmd_list);
|
|
INIT_LIST_HEAD(&worker->idle_list);
|
|
worker->lo = lo;
|
|
rb_link_node(&worker->rb_node, parent, node);
|
|
rb_insert_color(&worker->rb_node, &lo->worker_tree);
|
|
queue_work:
|
|
if (worker) {
|
|
/*
|
|
* We need to remove from the idle list here while
|
|
* holding the lock so that the idle timer doesn't
|
|
* free the worker
|
|
*/
|
|
if (!list_empty(&worker->idle_list))
|
|
list_del_init(&worker->idle_list);
|
|
work = &worker->work;
|
|
cmd_list = &worker->cmd_list;
|
|
} else {
|
|
work = &lo->rootcg_work;
|
|
cmd_list = &lo->rootcg_cmd_list;
|
|
}
|
|
list_add_tail(&cmd->list_entry, cmd_list);
|
|
queue_work(lo->workqueue, work);
|
|
spin_unlock_irq(&lo->lo_work_lock);
|
|
}
|
|
|
|
static void loop_update_rotational(struct loop_device *lo)
|
|
{
|
|
struct file *file = lo->lo_backing_file;
|
|
struct inode *file_inode = file->f_mapping->host;
|
|
struct block_device *file_bdev = file_inode->i_sb->s_bdev;
|
|
struct request_queue *q = lo->lo_queue;
|
|
bool nonrot = true;
|
|
|
|
/* not all filesystems (e.g. tmpfs) have a sb->s_bdev */
|
|
if (file_bdev)
|
|
nonrot = blk_queue_nonrot(bdev_get_queue(file_bdev));
|
|
|
|
if (nonrot)
|
|
blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
|
|
else
|
|
blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
|
|
}
|
|
|
|
/**
|
|
* loop_set_status_from_info - configure device from loop_info
|
|
* @lo: struct loop_device to configure
|
|
* @info: struct loop_info64 to configure the device with
|
|
*
|
|
* Configures the loop device parameters according to the passed
|
|
* in loop_info64 configuration.
|
|
*/
|
|
static int
|
|
loop_set_status_from_info(struct loop_device *lo,
|
|
const struct loop_info64 *info)
|
|
{
|
|
if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
|
|
return -EINVAL;
|
|
|
|
switch (info->lo_encrypt_type) {
|
|
case LO_CRYPT_NONE:
|
|
break;
|
|
case LO_CRYPT_XOR:
|
|
pr_warn("support for the xor transformation has been removed.\n");
|
|
return -EINVAL;
|
|
case LO_CRYPT_CRYPTOAPI:
|
|
pr_warn("support for cryptoloop has been removed. Use dm-crypt instead.\n");
|
|
return -EINVAL;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
lo->lo_offset = info->lo_offset;
|
|
lo->lo_sizelimit = info->lo_sizelimit;
|
|
memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
|
|
lo->lo_file_name[LO_NAME_SIZE-1] = 0;
|
|
lo->lo_flags = info->lo_flags;
|
|
return 0;
|
|
}
|
|
|
|
static int loop_configure(struct loop_device *lo, fmode_t mode,
|
|
struct block_device *bdev,
|
|
const struct loop_config *config)
|
|
{
|
|
struct file *file = fget(config->fd);
|
|
struct inode *inode;
|
|
struct address_space *mapping;
|
|
int error;
|
|
loff_t size;
|
|
bool partscan;
|
|
unsigned short bsize;
|
|
bool is_loop;
|
|
|
|
if (!file)
|
|
return -EBADF;
|
|
is_loop = is_loop_device(file);
|
|
|
|
/* This is safe, since we have a reference from open(). */
|
|
__module_get(THIS_MODULE);
|
|
|
|
/*
|
|
* If we don't hold exclusive handle for the device, upgrade to it
|
|
* here to avoid changing device under exclusive owner.
|
|
*/
|
|
if (!(mode & FMODE_EXCL)) {
|
|
error = bd_prepare_to_claim(bdev, loop_configure);
|
|
if (error)
|
|
goto out_putf;
|
|
}
|
|
|
|
error = loop_global_lock_killable(lo, is_loop);
|
|
if (error)
|
|
goto out_bdev;
|
|
|
|
error = -EBUSY;
|
|
if (lo->lo_state != Lo_unbound)
|
|
goto out_unlock;
|
|
|
|
error = loop_validate_file(file, bdev);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
mapping = file->f_mapping;
|
|
inode = mapping->host;
|
|
|
|
if ((config->info.lo_flags & ~LOOP_CONFIGURE_SETTABLE_FLAGS) != 0) {
|
|
error = -EINVAL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (config->block_size) {
|
|
error = blk_validate_block_size(config->block_size);
|
|
if (error)
|
|
goto out_unlock;
|
|
}
|
|
|
|
error = loop_set_status_from_info(lo, &config->info);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
|
|
!file->f_op->write_iter)
|
|
lo->lo_flags |= LO_FLAGS_READ_ONLY;
|
|
|
|
lo->workqueue = alloc_workqueue("loop%d",
|
|
WQ_UNBOUND | WQ_FREEZABLE,
|
|
0,
|
|
lo->lo_number);
|
|
if (!lo->workqueue) {
|
|
error = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
|
|
set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0);
|
|
|
|
INIT_WORK(&lo->rootcg_work, loop_rootcg_workfn);
|
|
INIT_LIST_HEAD(&lo->rootcg_cmd_list);
|
|
INIT_LIST_HEAD(&lo->idle_worker_list);
|
|
lo->worker_tree = RB_ROOT;
|
|
timer_setup(&lo->timer, loop_free_idle_workers,
|
|
TIMER_DEFERRABLE);
|
|
lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO;
|
|
lo->lo_device = bdev;
|
|
lo->lo_backing_file = file;
|
|
lo->old_gfp_mask = mapping_gfp_mask(mapping);
|
|
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
|
|
|
if (!(lo->lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
|
|
blk_queue_write_cache(lo->lo_queue, true, false);
|
|
|
|
if (config->block_size)
|
|
bsize = config->block_size;
|
|
else if ((lo->lo_backing_file->f_flags & O_DIRECT) && inode->i_sb->s_bdev)
|
|
/* In case of direct I/O, match underlying block size */
|
|
bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
|
|
else
|
|
bsize = 512;
|
|
|
|
blk_queue_logical_block_size(lo->lo_queue, bsize);
|
|
blk_queue_physical_block_size(lo->lo_queue, bsize);
|
|
blk_queue_io_min(lo->lo_queue, bsize);
|
|
|
|
loop_config_discard(lo);
|
|
loop_update_rotational(lo);
|
|
loop_update_dio(lo);
|
|
loop_sysfs_init(lo);
|
|
|
|
size = get_loop_size(lo, file);
|
|
loop_set_size(lo, size);
|
|
|
|
/* Order wrt reading lo_state in loop_validate_file(). */
|
|
wmb();
|
|
|
|
lo->lo_state = Lo_bound;
|
|
if (part_shift)
|
|
lo->lo_flags |= LO_FLAGS_PARTSCAN;
|
|
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
|
|
if (partscan)
|
|
lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
|
|
|
|
loop_global_unlock(lo, is_loop);
|
|
if (partscan)
|
|
loop_reread_partitions(lo);
|
|
if (!(mode & FMODE_EXCL))
|
|
bd_abort_claiming(bdev, loop_configure);
|
|
return 0;
|
|
|
|
out_unlock:
|
|
loop_global_unlock(lo, is_loop);
|
|
out_bdev:
|
|
if (!(mode & FMODE_EXCL))
|
|
bd_abort_claiming(bdev, loop_configure);
|
|
out_putf:
|
|
fput(file);
|
|
/* This is safe: open() is still holding a reference. */
|
|
module_put(THIS_MODULE);
|
|
return error;
|
|
}
|
|
|
|
static void __loop_clr_fd(struct loop_device *lo)
|
|
{
|
|
struct file *filp;
|
|
gfp_t gfp = lo->old_gfp_mask;
|
|
struct loop_worker *pos, *worker;
|
|
|
|
/*
|
|
* Flush loop_configure() and loop_change_fd(). It is acceptable for
|
|
* loop_validate_file() to succeed, for actual clear operation has not
|
|
* started yet.
|
|
*/
|
|
mutex_lock(&loop_validate_mutex);
|
|
mutex_unlock(&loop_validate_mutex);
|
|
/*
|
|
* loop_validate_file() now fails because l->lo_state != Lo_bound
|
|
* became visible.
|
|
*/
|
|
|
|
/*
|
|
* Since this function is called upon "ioctl(LOOP_CLR_FD)" xor "close()
|
|
* after ioctl(LOOP_CLR_FD)", it is a sign of something going wrong if
|
|
* lo->lo_state has changed while waiting for lo->lo_mutex.
|
|
*/
|
|
mutex_lock(&lo->lo_mutex);
|
|
BUG_ON(lo->lo_state != Lo_rundown);
|
|
mutex_unlock(&lo->lo_mutex);
|
|
|
|
if (test_bit(QUEUE_FLAG_WC, &lo->lo_queue->queue_flags))
|
|
blk_queue_write_cache(lo->lo_queue, false, false);
|
|
|
|
/* freeze request queue during the transition */
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
destroy_workqueue(lo->workqueue);
|
|
spin_lock_irq(&lo->lo_work_lock);
|
|
list_for_each_entry_safe(worker, pos, &lo->idle_worker_list,
|
|
idle_list) {
|
|
list_del(&worker->idle_list);
|
|
rb_erase(&worker->rb_node, &lo->worker_tree);
|
|
css_put(worker->blkcg_css);
|
|
kfree(worker);
|
|
}
|
|
spin_unlock_irq(&lo->lo_work_lock);
|
|
del_timer_sync(&lo->timer);
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
filp = lo->lo_backing_file;
|
|
lo->lo_backing_file = NULL;
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
lo->lo_device = NULL;
|
|
lo->lo_offset = 0;
|
|
lo->lo_sizelimit = 0;
|
|
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
|
|
blk_queue_logical_block_size(lo->lo_queue, 512);
|
|
blk_queue_physical_block_size(lo->lo_queue, 512);
|
|
blk_queue_io_min(lo->lo_queue, 512);
|
|
invalidate_disk(lo->lo_disk);
|
|
loop_sysfs_exit(lo);
|
|
/* let user-space know about this change */
|
|
kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE);
|
|
mapping_set_gfp_mask(filp->f_mapping, gfp);
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE);
|
|
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN) {
|
|
int err;
|
|
|
|
mutex_lock(&lo->lo_disk->open_mutex);
|
|
err = bdev_disk_changed(lo->lo_disk, false);
|
|
mutex_unlock(&lo->lo_disk->open_mutex);
|
|
if (err)
|
|
pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
|
|
__func__, lo->lo_number, err);
|
|
/* Device is gone, no point in returning error */
|
|
}
|
|
|
|
lo->lo_flags = 0;
|
|
if (!part_shift)
|
|
lo->lo_disk->flags |= GENHD_FL_NO_PART;
|
|
|
|
fput(filp);
|
|
}
|
|
|
|
static void loop_rundown_completed(struct loop_device *lo)
|
|
{
|
|
mutex_lock(&lo->lo_mutex);
|
|
lo->lo_state = Lo_unbound;
|
|
mutex_unlock(&lo->lo_mutex);
|
|
module_put(THIS_MODULE);
|
|
}
|
|
|
|
static void loop_rundown_workfn(struct work_struct *work)
|
|
{
|
|
struct loop_device *lo = container_of(work, struct loop_device,
|
|
rundown_work);
|
|
struct block_device *bdev = lo->lo_device;
|
|
struct gendisk *disk = lo->lo_disk;
|
|
|
|
__loop_clr_fd(lo);
|
|
kobject_put(&bdev->bd_device.kobj);
|
|
module_put(disk->fops->owner);
|
|
loop_rundown_completed(lo);
|
|
}
|
|
|
|
static void loop_schedule_rundown(struct loop_device *lo)
|
|
{
|
|
struct block_device *bdev = lo->lo_device;
|
|
struct gendisk *disk = lo->lo_disk;
|
|
|
|
__module_get(disk->fops->owner);
|
|
kobject_get(&bdev->bd_device.kobj);
|
|
INIT_WORK(&lo->rundown_work, loop_rundown_workfn);
|
|
queue_work(system_long_wq, &lo->rundown_work);
|
|
}
|
|
|
|
static int loop_clr_fd(struct loop_device *lo)
|
|
{
|
|
int err;
|
|
|
|
err = mutex_lock_killable(&lo->lo_mutex);
|
|
if (err)
|
|
return err;
|
|
if (lo->lo_state != Lo_bound) {
|
|
mutex_unlock(&lo->lo_mutex);
|
|
return -ENXIO;
|
|
}
|
|
/*
|
|
* If we've explicitly asked to tear down the loop device,
|
|
* and it has an elevated reference count, set it for auto-teardown when
|
|
* the last reference goes away. This stops $!~#$@ udev from
|
|
* preventing teardown because it decided that it needs to run blkid on
|
|
* the loopback device whenever they appear. xfstests is notorious for
|
|
* failing tests because blkid via udev races with a losetup
|
|
* <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d
|
|
* command to fail with EBUSY.
|
|
*/
|
|
if (atomic_read(&lo->lo_refcnt) > 1) {
|
|
lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
|
|
mutex_unlock(&lo->lo_mutex);
|
|
return 0;
|
|
}
|
|
lo->lo_state = Lo_rundown;
|
|
mutex_unlock(&lo->lo_mutex);
|
|
|
|
__loop_clr_fd(lo);
|
|
loop_rundown_completed(lo);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
|
|
{
|
|
int err;
|
|
int prev_lo_flags;
|
|
bool partscan = false;
|
|
bool size_changed = false;
|
|
|
|
err = mutex_lock_killable(&lo->lo_mutex);
|
|
if (err)
|
|
return err;
|
|
if (lo->lo_state != Lo_bound) {
|
|
err = -ENXIO;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (lo->lo_offset != info->lo_offset ||
|
|
lo->lo_sizelimit != info->lo_sizelimit) {
|
|
size_changed = true;
|
|
sync_blockdev(lo->lo_device);
|
|
invalidate_bdev(lo->lo_device);
|
|
}
|
|
|
|
/* I/O need to be drained during transfer transition */
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
|
|
/* If any pages were dirtied after invalidate_bdev(), try again */
|
|
err = -EAGAIN;
|
|
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
|
|
__func__, lo->lo_number, lo->lo_file_name,
|
|
lo->lo_device->bd_inode->i_mapping->nrpages);
|
|
goto out_unfreeze;
|
|
}
|
|
|
|
prev_lo_flags = lo->lo_flags;
|
|
|
|
err = loop_set_status_from_info(lo, info);
|
|
if (err)
|
|
goto out_unfreeze;
|
|
|
|
/* Mask out flags that can't be set using LOOP_SET_STATUS. */
|
|
lo->lo_flags &= LOOP_SET_STATUS_SETTABLE_FLAGS;
|
|
/* For those flags, use the previous values instead */
|
|
lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_SETTABLE_FLAGS;
|
|
/* For flags that can't be cleared, use previous values too */
|
|
lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_CLEARABLE_FLAGS;
|
|
|
|
if (size_changed) {
|
|
loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
|
|
lo->lo_backing_file);
|
|
loop_set_size(lo, new_size);
|
|
}
|
|
|
|
loop_config_discard(lo);
|
|
|
|
/* update dio if lo_offset or transfer is changed */
|
|
__loop_update_dio(lo, lo->use_dio);
|
|
|
|
out_unfreeze:
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
|
|
!(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
|
|
lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
|
|
partscan = true;
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&lo->lo_mutex);
|
|
if (partscan)
|
|
loop_reread_partitions(lo);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
loop_get_status(struct loop_device *lo, struct loop_info64 *info)
|
|
{
|
|
struct path path;
|
|
struct kstat stat;
|
|
int ret;
|
|
|
|
ret = mutex_lock_killable(&lo->lo_mutex);
|
|
if (ret)
|
|
return ret;
|
|
if (lo->lo_state != Lo_bound) {
|
|
mutex_unlock(&lo->lo_mutex);
|
|
return -ENXIO;
|
|
}
|
|
|
|
memset(info, 0, sizeof(*info));
|
|
info->lo_number = lo->lo_number;
|
|
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);
|
|
|
|
/* Drop lo_mutex while we call into the filesystem. */
|
|
path = lo->lo_backing_file->f_path;
|
|
path_get(&path);
|
|
mutex_unlock(&lo->lo_mutex);
|
|
ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT);
|
|
if (!ret) {
|
|
info->lo_device = huge_encode_dev(stat.dev);
|
|
info->lo_inode = stat.ino;
|
|
info->lo_rdevice = huge_encode_dev(stat.rdev);
|
|
}
|
|
path_put(&path);
|
|
return ret;
|
|
}
|
|
|
|
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_flags = info->lo_flags;
|
|
memcpy(info64->lo_file_name, info->lo_name, LO_NAME_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_flags = info64->lo_flags;
|
|
memcpy(info->lo_name, info64->lo_file_name, LO_NAME_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;
|
|
|
|
if (!arg)
|
|
return -EINVAL;
|
|
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;
|
|
|
|
if (!arg)
|
|
return -EINVAL;
|
|
err = loop_get_status(lo, &info64);
|
|
if (!err && copy_to_user(arg, &info64, sizeof(info64)))
|
|
err = -EFAULT;
|
|
|
|
return err;
|
|
}
|
|
|
|
static int loop_set_capacity(struct loop_device *lo)
|
|
{
|
|
loff_t size;
|
|
|
|
if (unlikely(lo->lo_state != Lo_bound))
|
|
return -ENXIO;
|
|
|
|
size = get_loop_size(lo, lo->lo_backing_file);
|
|
loop_set_size(lo, size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int loop_set_dio(struct loop_device *lo, unsigned long arg)
|
|
{
|
|
int error = -ENXIO;
|
|
if (lo->lo_state != Lo_bound)
|
|
goto out;
|
|
|
|
__loop_update_dio(lo, !!arg);
|
|
if (lo->use_dio == !!arg)
|
|
return 0;
|
|
error = -EINVAL;
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
|
|
{
|
|
int err = 0;
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
return -ENXIO;
|
|
|
|
err = blk_validate_block_size(arg);
|
|
if (err)
|
|
return err;
|
|
|
|
if (lo->lo_queue->limits.logical_block_size == arg)
|
|
return 0;
|
|
|
|
sync_blockdev(lo->lo_device);
|
|
invalidate_bdev(lo->lo_device);
|
|
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
/* invalidate_bdev should have truncated all the pages */
|
|
if (lo->lo_device->bd_inode->i_mapping->nrpages) {
|
|
err = -EAGAIN;
|
|
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
|
|
__func__, lo->lo_number, lo->lo_file_name,
|
|
lo->lo_device->bd_inode->i_mapping->nrpages);
|
|
goto out_unfreeze;
|
|
}
|
|
|
|
blk_queue_logical_block_size(lo->lo_queue, arg);
|
|
blk_queue_physical_block_size(lo->lo_queue, arg);
|
|
blk_queue_io_min(lo->lo_queue, arg);
|
|
loop_update_dio(lo);
|
|
out_unfreeze:
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
int err;
|
|
|
|
err = mutex_lock_killable(&lo->lo_mutex);
|
|
if (err)
|
|
return err;
|
|
switch (cmd) {
|
|
case LOOP_SET_CAPACITY:
|
|
err = loop_set_capacity(lo);
|
|
break;
|
|
case LOOP_SET_DIRECT_IO:
|
|
err = loop_set_dio(lo, arg);
|
|
break;
|
|
case LOOP_SET_BLOCK_SIZE:
|
|
err = loop_set_block_size(lo, arg);
|
|
break;
|
|
default:
|
|
err = -EINVAL;
|
|
}
|
|
mutex_unlock(&lo->lo_mutex);
|
|
return err;
|
|
}
|
|
|
|
static int lo_ioctl(struct block_device *bdev, fmode_t mode,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct loop_device *lo = bdev->bd_disk->private_data;
|
|
void __user *argp = (void __user *) arg;
|
|
int err;
|
|
|
|
switch (cmd) {
|
|
case LOOP_SET_FD: {
|
|
/*
|
|
* Legacy case - pass in a zeroed out struct loop_config with
|
|
* only the file descriptor set , which corresponds with the
|
|
* default parameters we'd have used otherwise.
|
|
*/
|
|
struct loop_config config;
|
|
|
|
memset(&config, 0, sizeof(config));
|
|
config.fd = arg;
|
|
|
|
return loop_configure(lo, mode, bdev, &config);
|
|
}
|
|
case LOOP_CONFIGURE: {
|
|
struct loop_config config;
|
|
|
|
if (copy_from_user(&config, argp, sizeof(config)))
|
|
return -EFAULT;
|
|
|
|
return loop_configure(lo, mode, bdev, &config);
|
|
}
|
|
case LOOP_CHANGE_FD:
|
|
return loop_change_fd(lo, bdev, arg);
|
|
case LOOP_CLR_FD:
|
|
return loop_clr_fd(lo);
|
|
case LOOP_SET_STATUS:
|
|
err = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
|
|
err = loop_set_status_old(lo, argp);
|
|
}
|
|
break;
|
|
case LOOP_GET_STATUS:
|
|
return loop_get_status_old(lo, argp);
|
|
case LOOP_SET_STATUS64:
|
|
err = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
|
|
err = loop_set_status64(lo, argp);
|
|
}
|
|
break;
|
|
case LOOP_GET_STATUS64:
|
|
return loop_get_status64(lo, argp);
|
|
case LOOP_SET_CAPACITY:
|
|
case LOOP_SET_DIRECT_IO:
|
|
case LOOP_SET_BLOCK_SIZE:
|
|
if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
fallthrough;
|
|
default:
|
|
err = lo_simple_ioctl(lo, cmd, arg);
|
|
break;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
struct compat_loop_info {
|
|
compat_int_t lo_number; /* ioctl r/o */
|
|
compat_dev_t lo_device; /* ioctl r/o */
|
|
compat_ulong_t lo_inode; /* ioctl r/o */
|
|
compat_dev_t lo_rdevice; /* ioctl r/o */
|
|
compat_int_t lo_offset;
|
|
compat_int_t lo_encrypt_key_size; /* ioctl w/o */
|
|
compat_int_t lo_flags; /* ioctl r/o */
|
|
char lo_name[LO_NAME_SIZE];
|
|
unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
|
|
compat_ulong_t lo_init[2];
|
|
char reserved[4];
|
|
};
|
|
|
|
/*
|
|
* Transfer 32-bit compatibility structure in userspace to 64-bit loop info
|
|
* - noinlined to reduce stack space usage in main part of driver
|
|
*/
|
|
static noinline int
|
|
loop_info64_from_compat(const struct compat_loop_info __user *arg,
|
|
struct loop_info64 *info64)
|
|
{
|
|
struct compat_loop_info info;
|
|
|
|
if (copy_from_user(&info, arg, sizeof(info)))
|
|
return -EFAULT;
|
|
|
|
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_flags = info.lo_flags;
|
|
memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Transfer 64-bit loop info to 32-bit compatibility structure in userspace
|
|
* - noinlined to reduce stack space usage in main part of driver
|
|
*/
|
|
static noinline int
|
|
loop_info64_to_compat(const struct loop_info64 *info64,
|
|
struct compat_loop_info __user *arg)
|
|
{
|
|
struct compat_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_flags = info64->lo_flags;
|
|
memcpy(info.lo_name, info64->lo_file_name, LO_NAME_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;
|
|
|
|
if (copy_to_user(arg, &info, sizeof(info)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
loop_set_status_compat(struct loop_device *lo,
|
|
const struct compat_loop_info __user *arg)
|
|
{
|
|
struct loop_info64 info64;
|
|
int ret;
|
|
|
|
ret = loop_info64_from_compat(arg, &info64);
|
|
if (ret < 0)
|
|
return ret;
|
|
return loop_set_status(lo, &info64);
|
|
}
|
|
|
|
static int
|
|
loop_get_status_compat(struct loop_device *lo,
|
|
struct compat_loop_info __user *arg)
|
|
{
|
|
struct loop_info64 info64;
|
|
int err;
|
|
|
|
if (!arg)
|
|
return -EINVAL;
|
|
err = loop_get_status(lo, &info64);
|
|
if (!err)
|
|
err = loop_info64_to_compat(&info64, arg);
|
|
return err;
|
|
}
|
|
|
|
static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct loop_device *lo = bdev->bd_disk->private_data;
|
|
int err;
|
|
|
|
switch(cmd) {
|
|
case LOOP_SET_STATUS:
|
|
err = loop_set_status_compat(lo,
|
|
(const struct compat_loop_info __user *)arg);
|
|
break;
|
|
case LOOP_GET_STATUS:
|
|
err = loop_get_status_compat(lo,
|
|
(struct compat_loop_info __user *)arg);
|
|
break;
|
|
case LOOP_SET_CAPACITY:
|
|
case LOOP_CLR_FD:
|
|
case LOOP_GET_STATUS64:
|
|
case LOOP_SET_STATUS64:
|
|
case LOOP_CONFIGURE:
|
|
arg = (unsigned long) compat_ptr(arg);
|
|
fallthrough;
|
|
case LOOP_SET_FD:
|
|
case LOOP_CHANGE_FD:
|
|
case LOOP_SET_BLOCK_SIZE:
|
|
case LOOP_SET_DIRECT_IO:
|
|
err = lo_ioctl(bdev, mode, cmd, arg);
|
|
break;
|
|
default:
|
|
err = -ENOIOCTLCMD;
|
|
break;
|
|
}
|
|
return err;
|
|
}
|
|
#endif
|
|
|
|
static int lo_open(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
struct loop_device *lo = bdev->bd_disk->private_data;
|
|
int err;
|
|
|
|
err = mutex_lock_killable(&lo->lo_mutex);
|
|
if (err)
|
|
return err;
|
|
if (lo->lo_state == Lo_deleting)
|
|
err = -ENXIO;
|
|
else
|
|
atomic_inc(&lo->lo_refcnt);
|
|
mutex_unlock(&lo->lo_mutex);
|
|
return err;
|
|
}
|
|
|
|
static void lo_release(struct gendisk *disk, fmode_t mode)
|
|
{
|
|
struct loop_device *lo = disk->private_data;
|
|
|
|
mutex_lock(&lo->lo_mutex);
|
|
if (atomic_dec_return(&lo->lo_refcnt))
|
|
goto out_unlock;
|
|
|
|
if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
|
|
if (lo->lo_state != Lo_bound)
|
|
goto out_unlock;
|
|
lo->lo_state = Lo_rundown;
|
|
mutex_unlock(&lo->lo_mutex);
|
|
/*
|
|
* In autoclear mode, stop the loop thread
|
|
* and remove configuration after last close.
|
|
*/
|
|
loop_schedule_rundown(lo);
|
|
return;
|
|
} else if (lo->lo_state == Lo_bound) {
|
|
/*
|
|
* Otherwise keep thread (if running) and config,
|
|
* but flush possible ongoing bios in thread.
|
|
*/
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
}
|
|
|
|
out_unlock:
|
|
mutex_unlock(&lo->lo_mutex);
|
|
}
|
|
|
|
static const struct block_device_operations lo_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = lo_open,
|
|
.release = lo_release,
|
|
.ioctl = lo_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = lo_compat_ioctl,
|
|
#endif
|
|
};
|
|
|
|
/*
|
|
* And now the modules code and kernel interface.
|
|
*/
|
|
static int max_loop;
|
|
module_param(max_loop, int, 0444);
|
|
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
|
|
module_param(max_part, int, 0444);
|
|
MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
|
|
|
|
static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
|
|
const struct blk_mq_queue_data *bd)
|
|
{
|
|
struct request *rq = bd->rq;
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
|
|
struct loop_device *lo = rq->q->queuedata;
|
|
|
|
blk_mq_start_request(rq);
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
return BLK_STS_IOERR;
|
|
|
|
switch (req_op(rq)) {
|
|
case REQ_OP_FLUSH:
|
|
case REQ_OP_DISCARD:
|
|
case REQ_OP_WRITE_ZEROES:
|
|
cmd->use_aio = false;
|
|
break;
|
|
default:
|
|
cmd->use_aio = lo->use_dio;
|
|
break;
|
|
}
|
|
|
|
/* always use the first bio's css */
|
|
cmd->blkcg_css = NULL;
|
|
cmd->memcg_css = NULL;
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
if (rq->bio && rq->bio->bi_blkg) {
|
|
cmd->blkcg_css = &bio_blkcg(rq->bio)->css;
|
|
#ifdef CONFIG_MEMCG
|
|
cmd->memcg_css =
|
|
cgroup_get_e_css(cmd->blkcg_css->cgroup,
|
|
&memory_cgrp_subsys);
|
|
#endif
|
|
}
|
|
#endif
|
|
loop_queue_work(lo, cmd);
|
|
|
|
return BLK_STS_OK;
|
|
}
|
|
|
|
static void loop_handle_cmd(struct loop_cmd *cmd)
|
|
{
|
|
struct request *rq = blk_mq_rq_from_pdu(cmd);
|
|
const bool write = op_is_write(req_op(rq));
|
|
struct loop_device *lo = rq->q->queuedata;
|
|
int ret = 0;
|
|
struct mem_cgroup *old_memcg = NULL;
|
|
|
|
if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) {
|
|
ret = -EIO;
|
|
goto failed;
|
|
}
|
|
|
|
if (cmd->blkcg_css)
|
|
kthread_associate_blkcg(cmd->blkcg_css);
|
|
if (cmd->memcg_css)
|
|
old_memcg = set_active_memcg(
|
|
mem_cgroup_from_css(cmd->memcg_css));
|
|
|
|
ret = do_req_filebacked(lo, rq);
|
|
|
|
if (cmd->blkcg_css)
|
|
kthread_associate_blkcg(NULL);
|
|
|
|
if (cmd->memcg_css) {
|
|
set_active_memcg(old_memcg);
|
|
css_put(cmd->memcg_css);
|
|
}
|
|
failed:
|
|
/* complete non-aio request */
|
|
if (!cmd->use_aio || ret) {
|
|
if (ret == -EOPNOTSUPP)
|
|
cmd->ret = ret;
|
|
else
|
|
cmd->ret = ret ? -EIO : 0;
|
|
if (likely(!blk_should_fake_timeout(rq->q)))
|
|
blk_mq_complete_request(rq);
|
|
}
|
|
}
|
|
|
|
static void loop_set_timer(struct loop_device *lo)
|
|
{
|
|
timer_reduce(&lo->timer, jiffies + LOOP_IDLE_WORKER_TIMEOUT);
|
|
}
|
|
|
|
static void loop_process_work(struct loop_worker *worker,
|
|
struct list_head *cmd_list, struct loop_device *lo)
|
|
{
|
|
int orig_flags = current->flags;
|
|
struct loop_cmd *cmd;
|
|
|
|
current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO;
|
|
spin_lock_irq(&lo->lo_work_lock);
|
|
while (!list_empty(cmd_list)) {
|
|
cmd = container_of(
|
|
cmd_list->next, struct loop_cmd, list_entry);
|
|
list_del(cmd_list->next);
|
|
spin_unlock_irq(&lo->lo_work_lock);
|
|
|
|
loop_handle_cmd(cmd);
|
|
cond_resched();
|
|
|
|
spin_lock_irq(&lo->lo_work_lock);
|
|
}
|
|
|
|
/*
|
|
* We only add to the idle list if there are no pending cmds
|
|
* *and* the worker will not run again which ensures that it
|
|
* is safe to free any worker on the idle list
|
|
*/
|
|
if (worker && !work_pending(&worker->work)) {
|
|
worker->last_ran_at = jiffies;
|
|
list_add_tail(&worker->idle_list, &lo->idle_worker_list);
|
|
loop_set_timer(lo);
|
|
}
|
|
spin_unlock_irq(&lo->lo_work_lock);
|
|
current->flags = orig_flags;
|
|
}
|
|
|
|
static void loop_workfn(struct work_struct *work)
|
|
{
|
|
struct loop_worker *worker =
|
|
container_of(work, struct loop_worker, work);
|
|
loop_process_work(worker, &worker->cmd_list, worker->lo);
|
|
}
|
|
|
|
static void loop_rootcg_workfn(struct work_struct *work)
|
|
{
|
|
struct loop_device *lo =
|
|
container_of(work, struct loop_device, rootcg_work);
|
|
loop_process_work(NULL, &lo->rootcg_cmd_list, lo);
|
|
}
|
|
|
|
static void loop_free_idle_workers(struct timer_list *timer)
|
|
{
|
|
struct loop_device *lo = container_of(timer, struct loop_device, timer);
|
|
struct loop_worker *pos, *worker;
|
|
|
|
spin_lock_irq(&lo->lo_work_lock);
|
|
list_for_each_entry_safe(worker, pos, &lo->idle_worker_list,
|
|
idle_list) {
|
|
if (time_is_after_jiffies(worker->last_ran_at +
|
|
LOOP_IDLE_WORKER_TIMEOUT))
|
|
break;
|
|
list_del(&worker->idle_list);
|
|
rb_erase(&worker->rb_node, &lo->worker_tree);
|
|
css_put(worker->blkcg_css);
|
|
kfree(worker);
|
|
}
|
|
if (!list_empty(&lo->idle_worker_list))
|
|
loop_set_timer(lo);
|
|
spin_unlock_irq(&lo->lo_work_lock);
|
|
}
|
|
|
|
static const struct blk_mq_ops loop_mq_ops = {
|
|
.queue_rq = loop_queue_rq,
|
|
.complete = lo_complete_rq,
|
|
};
|
|
|
|
static int loop_add(int i)
|
|
{
|
|
struct loop_device *lo;
|
|
struct gendisk *disk;
|
|
int err;
|
|
|
|
err = -ENOMEM;
|
|
lo = kzalloc(sizeof(*lo), GFP_KERNEL);
|
|
if (!lo)
|
|
goto out;
|
|
lo->lo_state = Lo_unbound;
|
|
|
|
err = mutex_lock_killable(&loop_ctl_mutex);
|
|
if (err)
|
|
goto out_free_dev;
|
|
|
|
/* allocate id, if @id >= 0, we're requesting that specific id */
|
|
if (i >= 0) {
|
|
err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL);
|
|
if (err == -ENOSPC)
|
|
err = -EEXIST;
|
|
} else {
|
|
err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL);
|
|
}
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
if (err < 0)
|
|
goto out_free_dev;
|
|
i = err;
|
|
|
|
lo->tag_set.ops = &loop_mq_ops;
|
|
lo->tag_set.nr_hw_queues = 1;
|
|
lo->tag_set.queue_depth = 128;
|
|
lo->tag_set.numa_node = NUMA_NO_NODE;
|
|
lo->tag_set.cmd_size = sizeof(struct loop_cmd);
|
|
lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING |
|
|
BLK_MQ_F_NO_SCHED_BY_DEFAULT;
|
|
lo->tag_set.driver_data = lo;
|
|
|
|
err = blk_mq_alloc_tag_set(&lo->tag_set);
|
|
if (err)
|
|
goto out_free_idr;
|
|
|
|
disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, lo);
|
|
if (IS_ERR(disk)) {
|
|
err = PTR_ERR(disk);
|
|
goto out_cleanup_tags;
|
|
}
|
|
lo->lo_queue = lo->lo_disk->queue;
|
|
|
|
blk_queue_max_hw_sectors(lo->lo_queue, BLK_DEF_MAX_SECTORS);
|
|
|
|
/*
|
|
* By default, we do buffer IO, so it doesn't make sense to enable
|
|
* merge because the I/O submitted to backing file is handled page by
|
|
* page. For directio mode, merge does help to dispatch bigger request
|
|
* to underlayer disk. We will enable merge once directio is enabled.
|
|
*/
|
|
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue);
|
|
|
|
/*
|
|
* Disable partition scanning by default. The in-kernel partition
|
|
* scanning can be requested individually per-device during its
|
|
* setup. Userspace can always add and remove partitions from all
|
|
* devices. The needed partition minors are allocated from the
|
|
* extended minor space, the main loop device numbers will continue
|
|
* to match the loop minors, regardless of the number of partitions
|
|
* used.
|
|
*
|
|
* If max_part is given, partition scanning is globally enabled for
|
|
* all loop devices. The minors for the main loop devices will be
|
|
* multiples of max_part.
|
|
*
|
|
* Note: Global-for-all-devices, set-only-at-init, read-only module
|
|
* parameteters like 'max_loop' and 'max_part' make things needlessly
|
|
* complicated, are too static, inflexible and may surprise
|
|
* userspace tools. Parameters like this in general should be avoided.
|
|
*/
|
|
if (!part_shift)
|
|
disk->flags |= GENHD_FL_NO_PART;
|
|
atomic_set(&lo->lo_refcnt, 0);
|
|
mutex_init(&lo->lo_mutex);
|
|
lo->lo_number = i;
|
|
spin_lock_init(&lo->lo_lock);
|
|
spin_lock_init(&lo->lo_work_lock);
|
|
disk->major = LOOP_MAJOR;
|
|
disk->first_minor = i << part_shift;
|
|
disk->minors = 1 << part_shift;
|
|
disk->fops = &lo_fops;
|
|
disk->private_data = lo;
|
|
disk->queue = lo->lo_queue;
|
|
disk->events = DISK_EVENT_MEDIA_CHANGE;
|
|
disk->event_flags = DISK_EVENT_FLAG_UEVENT;
|
|
sprintf(disk->disk_name, "loop%d", i);
|
|
/* Make this loop device reachable from pathname. */
|
|
err = add_disk(disk);
|
|
if (err)
|
|
goto out_cleanup_disk;
|
|
|
|
/* Show this loop device. */
|
|
mutex_lock(&loop_ctl_mutex);
|
|
lo->idr_visible = true;
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
|
|
return i;
|
|
|
|
out_cleanup_disk:
|
|
blk_cleanup_disk(disk);
|
|
out_cleanup_tags:
|
|
blk_mq_free_tag_set(&lo->tag_set);
|
|
out_free_idr:
|
|
mutex_lock(&loop_ctl_mutex);
|
|
idr_remove(&loop_index_idr, i);
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
out_free_dev:
|
|
kfree(lo);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static void loop_remove(struct loop_device *lo)
|
|
{
|
|
/* Make this loop device unreachable from pathname. */
|
|
del_gendisk(lo->lo_disk);
|
|
blk_cleanup_disk(lo->lo_disk);
|
|
blk_mq_free_tag_set(&lo->tag_set);
|
|
mutex_lock(&loop_ctl_mutex);
|
|
idr_remove(&loop_index_idr, lo->lo_number);
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
/* There is no route which can find this loop device. */
|
|
mutex_destroy(&lo->lo_mutex);
|
|
kfree(lo);
|
|
}
|
|
|
|
static void loop_probe(dev_t dev)
|
|
{
|
|
int idx = MINOR(dev) >> part_shift;
|
|
|
|
if (max_loop && idx >= max_loop)
|
|
return;
|
|
loop_add(idx);
|
|
}
|
|
|
|
static int loop_control_remove(int idx)
|
|
{
|
|
struct loop_device *lo;
|
|
int ret;
|
|
|
|
if (idx < 0) {
|
|
pr_warn_once("deleting an unspecified loop device is not supported.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Hide this loop device for serialization. */
|
|
ret = mutex_lock_killable(&loop_ctl_mutex);
|
|
if (ret)
|
|
return ret;
|
|
lo = idr_find(&loop_index_idr, idx);
|
|
if (!lo || !lo->idr_visible)
|
|
ret = -ENODEV;
|
|
else
|
|
lo->idr_visible = false;
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Check whether this loop device can be removed. */
|
|
ret = mutex_lock_killable(&lo->lo_mutex);
|
|
if (ret)
|
|
goto mark_visible;
|
|
if (lo->lo_state != Lo_unbound ||
|
|
atomic_read(&lo->lo_refcnt) > 0) {
|
|
mutex_unlock(&lo->lo_mutex);
|
|
ret = -EBUSY;
|
|
goto mark_visible;
|
|
}
|
|
/* Mark this loop device no longer open()-able. */
|
|
lo->lo_state = Lo_deleting;
|
|
mutex_unlock(&lo->lo_mutex);
|
|
|
|
loop_remove(lo);
|
|
return 0;
|
|
|
|
mark_visible:
|
|
/* Show this loop device again. */
|
|
mutex_lock(&loop_ctl_mutex);
|
|
lo->idr_visible = true;
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
return ret;
|
|
}
|
|
|
|
static int loop_control_get_free(int idx)
|
|
{
|
|
struct loop_device *lo;
|
|
int id, ret;
|
|
|
|
ret = mutex_lock_killable(&loop_ctl_mutex);
|
|
if (ret)
|
|
return ret;
|
|
idr_for_each_entry(&loop_index_idr, lo, id) {
|
|
/* Hitting a race results in creating a new loop device which is harmless. */
|
|
if (lo->idr_visible && data_race(lo->lo_state) == Lo_unbound)
|
|
goto found;
|
|
}
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
return loop_add(-1);
|
|
found:
|
|
mutex_unlock(&loop_ctl_mutex);
|
|
return id;
|
|
}
|
|
|
|
static long loop_control_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long parm)
|
|
{
|
|
switch (cmd) {
|
|
case LOOP_CTL_ADD:
|
|
return loop_add(parm);
|
|
case LOOP_CTL_REMOVE:
|
|
return loop_control_remove(parm);
|
|
case LOOP_CTL_GET_FREE:
|
|
return loop_control_get_free(parm);
|
|
default:
|
|
return -ENOSYS;
|
|
}
|
|
}
|
|
|
|
static const struct file_operations loop_ctl_fops = {
|
|
.open = nonseekable_open,
|
|
.unlocked_ioctl = loop_control_ioctl,
|
|
.compat_ioctl = loop_control_ioctl,
|
|
.owner = THIS_MODULE,
|
|
.llseek = noop_llseek,
|
|
};
|
|
|
|
static struct miscdevice loop_misc = {
|
|
.minor = LOOP_CTRL_MINOR,
|
|
.name = "loop-control",
|
|
.fops = &loop_ctl_fops,
|
|
};
|
|
|
|
MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR);
|
|
MODULE_ALIAS("devname:loop-control");
|
|
|
|
static int __init loop_init(void)
|
|
{
|
|
int i, nr;
|
|
int err;
|
|
|
|
part_shift = 0;
|
|
if (max_part > 0) {
|
|
part_shift = fls(max_part);
|
|
|
|
/*
|
|
* Adjust max_part according to part_shift as it is exported
|
|
* to user space so that user can decide correct minor number
|
|
* if [s]he want to create more devices.
|
|
*
|
|
* Note that -1 is required because partition 0 is reserved
|
|
* for the whole disk.
|
|
*/
|
|
max_part = (1UL << part_shift) - 1;
|
|
}
|
|
|
|
if ((1UL << part_shift) > DISK_MAX_PARTS) {
|
|
err = -EINVAL;
|
|
goto err_out;
|
|
}
|
|
|
|
if (max_loop > 1UL << (MINORBITS - part_shift)) {
|
|
err = -EINVAL;
|
|
goto err_out;
|
|
}
|
|
|
|
/*
|
|
* If max_loop is specified, create that many devices upfront.
|
|
* This also becomes a hard limit. If max_loop is not specified,
|
|
* create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module
|
|
* init time. Loop devices can be requested on-demand with the
|
|
* /dev/loop-control interface, or be instantiated by accessing
|
|
* a 'dead' device node.
|
|
*/
|
|
if (max_loop)
|
|
nr = max_loop;
|
|
else
|
|
nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
|
|
|
|
err = misc_register(&loop_misc);
|
|
if (err < 0)
|
|
goto err_out;
|
|
|
|
|
|
if (__register_blkdev(LOOP_MAJOR, "loop", loop_probe)) {
|
|
err = -EIO;
|
|
goto misc_out;
|
|
}
|
|
|
|
/* pre-create number of devices given by config or max_loop */
|
|
for (i = 0; i < nr; i++)
|
|
loop_add(i);
|
|
|
|
printk(KERN_INFO "loop: module loaded\n");
|
|
return 0;
|
|
|
|
misc_out:
|
|
misc_deregister(&loop_misc);
|
|
err_out:
|
|
return err;
|
|
}
|
|
|
|
static void __exit loop_exit(void)
|
|
{
|
|
struct loop_device *lo;
|
|
int id;
|
|
|
|
unregister_blkdev(LOOP_MAJOR, "loop");
|
|
misc_deregister(&loop_misc);
|
|
|
|
/*
|
|
* There is no need to use loop_ctl_mutex here, for nobody else can
|
|
* access loop_index_idr when this module is unloading (unless forced
|
|
* module unloading is requested). If this is not a clean unloading,
|
|
* we have no means to avoid kernel crash.
|
|
*/
|
|
idr_for_each_entry(&loop_index_idr, lo, id)
|
|
loop_remove(lo);
|
|
|
|
idr_destroy(&loop_index_idr);
|
|
}
|
|
|
|
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
|