Release 4.14 drivers/block/loop.c

/*
 *  linux/drivers/block/loop.c
 *
 *  Written by Theodore Ts'o, 3/29/93
 *
 * Copyright 1993 by Theodore Ts'o.  Redistribution of this file is
 * permitted under the GNU General Public License.
 *
 * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
 * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
 *
 * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
 * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
 *
 * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
 *
 * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
 *
 * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
 *
 * Loadable modules and other fixes by AK, 1998
 *
 * Make real block number available to downstream transfer functions, enables
 * CBC (and relatives) mode encryption requiring unique IVs per data block.
 * Reed H. Petty, rhp@draper.net
 *
 * Maximum number of loop devices now dynamic via max_loop module parameter.
 * Russell Kroll <rkroll@exploits.org> 19990701
 *
 * Maximum number of loop devices when compiled-in now selectable by passing
 * max_loop=<1-255> to the kernel on boot.
 * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999
 *
 * Completely rewrite request handling to be make_request_fn style and
 * non blocking, pushing work to a helper thread. Lots of fixes from
 * Al Viro too.
 * Jens Axboe <axboe@suse.de>, Nov 2000
 *
 * Support up to 256 loop devices
 * Heinz Mauelshagen <mge@sistina.com>, Feb 2002
 *
 * Support for falling back on the write file operation when the address space
 * operations write_begin is not available on the backing filesystem.
 * Anton Altaparmakov, 16 Feb 2005
 *
 * Still To Fix:
 * - Advisory locking is ignored here.
 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/major.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/init.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/suspend.h>
#include <linux/freezer.h>
#include <linux/mutex.h>
#include <linux/writeback.h>
#include <linux/completion.h>
#include <linux/highmem.h>
#include <linux/kthread.h>
#include <linux/splice.h>
#include <linux/sysfs.h>
#include <linux/miscdevice.h>
#include <linux/falloc.h>
#include <linux/uio.h>
#include "loop.h"

#include <linux/uaccess.h>

static DEFINE_IDR(loop_index_idr);
static DEFINE_MUTEX(loop_index_mutex);


static int max_part;

static int part_shift;



static int transfer_xor(struct loop_device *lo, int cmd,
			struct page *raw_page, unsigned raw_off,
			struct page *loop_page, unsigned loop_off,
			int size, sector_t real_block)
{
	char *raw_buf = kmap_atomic(raw_page) + raw_off;
	char *loop_buf = kmap_atomic(loop_page) + loop_off;
	char *in, *out, *key;
	int i, keysize;

	if (cmd == READ) {
		in = raw_buf;
		out = loop_buf;
	} else {
		in = loop_buf;
		out = raw_buf;
	}

	key = lo->lo_encrypt_key;
	keysize = lo->lo_encrypt_key_size;
	for (i = 0; i < size; i++)
		*out++ = *in++ ^ key[(i & 511) % keysize];

	kunmap_atomic(loop_buf);
	kunmap_atomic(raw_buf);
	cond_resched();
	return 0;
}

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Linus Torvalds (pre-git)
112
70.00%
2
40.00%
Andrew Morton
46
28.75%
2
40.00%
Peter Zijlstra
2
1.25%
1
20.00%
Total
160
100.00%
5
100.00%



static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
{
	if (unlikely(info->lo_encrypt_key_size <= 0))
		return -EINVAL;
	return 0;
}

Contributors
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Linus Torvalds (pre-git)
29
82.86%
3
50.00%
Anton Altaparmakov
3
8.57%
1
16.67%
Andries E. Brouwer
3
8.57%
2
33.33%
Total
35
100.00%
6
100.00%


static struct loop_func_table none_funcs = {
	.number = LO_CRYPT_NONE,
}; 


static struct loop_func_table xor_funcs = {
	.number = LO_CRYPT_XOR,
	.transfer = transfer_xor,
	.init = xor_init
}; 

/* xfer_funcs[0] is special - its release function is never called */

static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
	&none_funcs,
	&xor_funcs
};



static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
{
	loff_t loopsize;

	/* Compute loopsize in bytes */
	loopsize = i_size_read(file->f_mapping->host);
	if (offset > 0)
		loopsize -= offset;
	/* offset is beyond i_size, weird but possible */
	if (loopsize < 0)
		return 0;

	if (sizelimit > 0 && sizelimit < loopsize)
		loopsize = sizelimit;
	/*
         * Unfortunately, if we want to do I/O on the device,
         * the number of 512-byte sectors has to fit into a sector_t.
         */
	return loopsize >> 9;
}

Contributors
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Andries E. Brouwer
22
30.56%
2
22.22%
Andrew Morton
18
25.00%
4
44.44%
Dmitriy Monakhov
18
25.00%
1
11.11%
Guo Chao
9
12.50%
1
11.11%
Linus Torvalds (pre-git)
5
6.94%
1
11.11%
Total
72
100.00%
9
100.00%



static loff_t get_loop_size(struct loop_device *lo, struct file *file)
{
	return get_size(lo->lo_offset, lo->lo_sizelimit, file);
}

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Dmitriy Monakhov
30
100.00%
1
100.00%
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30
100.00%
1
100.00%



static void __loop_update_dio(struct loop_device *lo, bool dio)
{
	struct file *file = lo->lo_backing_file;
	struct address_space *mapping = file->f_mapping;
	struct inode *inode = mapping->host;
	unsigned short sb_bsize = 0;
	unsigned dio_align = 0;
	bool use_dio;

	if (inode->i_sb->s_bdev) {
		sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
		dio_align = sb_bsize - 1;
	}

	/*
         * We support direct I/O only if lo_offset is aligned with the
         * logical I/O size of backing device, and the logical block
         * size of loop is bigger than the backing device's and the loop
         * needn't transform transfer.
         *
         * TODO: the above condition may be loosed in the future, and
         * direct I/O may be switched runtime at that time because most
         * of requests in sane applications should be PAGE_SIZE aligned
         */
	if (dio) {
		if (queue_logical_block_size(lo->lo_queue) >= sb_bsize &&
				!(lo->lo_offset & dio_align) &&
				mapping->a_ops->direct_IO &&
				!lo->transfer)
			use_dio = true;
		else
			use_dio = false;
	} else {
		use_dio = false;
	}

	if (lo->use_dio == use_dio)
		return;

	/* flush dirty pages before changing direct IO */
	vfs_fsync(file, 0);

	/*
         * The flag of LO_FLAGS_DIRECT_IO is handled similarly with
         * LO_FLAGS_READ_ONLY, both are set from kernel, and losetup
         * will get updated by ioctl(LOOP_GET_STATUS)
         */
	blk_mq_freeze_queue(lo->lo_queue);
	lo->use_dio = use_dio;
	if (use_dio) {
		queue_flag_clear_unlocked(QUEUE_FLAG_NOMERGES, lo->lo_queue);
		lo->lo_flags |= LO_FLAGS_DIRECT_IO;
	} else {
		queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, lo->lo_queue);
		lo->lo_flags &= ~LO_FLAGS_DIRECT_IO;
	}
	blk_mq_unfreeze_queue(lo->lo_queue);
}

Contributors
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Ming Lei
191
89.25%
1
33.33%
Shaohua Li
22
10.28%
1
33.33%
Masahiro Yamada
1
0.47%
1
33.33%
Total
214
100.00%
3
100.00%


static int

figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
{
	loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
	sector_t x = (sector_t)size;
	struct block_device *bdev = lo->lo_device;

	if (unlikely((loff_t)x != size))
		return -EFBIG;
	if (lo->lo_offset != offset)
		lo->lo_offset = offset;
	if (lo->lo_sizelimit != sizelimit)
		lo->lo_sizelimit = sizelimit;
	set_capacity(lo->lo_disk, x);
	bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
	/* let user-space know about the new size */
	kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
	return 0;
}

Contributors
Person
Tokens
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Commits
CommitProp
Andrew Morton
44
32.12%
2
22.22%
Guo Chao
42
30.66%
1
11.11%
Dmitriy Monakhov
38
27.74%
1
11.11%
Al Viro
4
2.92%
1
11.11%
Linus Torvalds (pre-git)
4
2.92%
1
11.11%
Anton Altaparmakov
3
2.19%
1
11.11%
Ken Chen
1
0.73%
1
11.11%
Andries E. Brouwer
1
0.73%
1
11.11%
Total
137
100.00%
9
100.00%


static inline int

lo_do_transfer(struct loop_device *lo, int cmd,
	       struct page *rpage, unsigned roffs,
	       struct page *lpage, unsigned loffs,
	       int size, sector_t rblock)
{
	int ret;

	ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
	if (likely(!ret))
		return 0;

	printk_ratelimited(KERN_ERR
		"loop: Transfer error at byte offset %llu, length %i.\n",
		(unsigned long long)rblock << 9, size);
	return ret;
}

Contributors
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Tokens
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CommitProp
Andrew Morton
58
61.70%
3
75.00%
Christoph Hellwig
36
38.30%
1
25.00%
Total
94
100.00%
4
100.00%



static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
{
	struct iov_iter i;
	ssize_t bw;

	iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len);

	file_start_write(file);
	bw = vfs_iter_write(file, &i, ppos, 0);
	file_end_write(file);

	if (likely(bw ==  bvec->bv_len))
		return 0;

	printk_ratelimited(KERN_ERR
		"loop: Write error at byte offset %llu, length %i.\n",
		(unsigned long long)*ppos, bvec->bv_len);
	if (bw >= 0)
		bw = -EIO;
	return bw;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Anton Altaparmakov
64
56.64%
1
14.29%
Christoph Hellwig
26
23.01%
2
28.57%
Al Viro
21
18.58%
2
28.57%
Mike Galbraith
1
0.88%
1
14.29%
Linus Torvalds
1
0.88%
1
14.29%
Total
113
100.00%
7
100.00%



static int lo_write_simple(struct loop_device *lo, struct request *rq,
		loff_t pos)
{
	struct bio_vec bvec;
	struct req_iterator iter;
	int ret = 0;

	rq_for_each_segment(bvec, rq, iter) {
		ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
		if (ret < 0)
			break;
		cond_resched();
	}

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
38
54.29%
1
50.00%
Anton Altaparmakov
32
45.71%
1
50.00%
Total
70
100.00%
2
100.00%

/*
 * This is the slow, transforming version that needs to double buffer the
 * data as it cannot do the transformations in place without having direct
 * access to the destination pages of the backing file.
 */


static int lo_write_transfer(struct loop_device *lo, struct request *rq,
		loff_t pos)
{
	struct bio_vec bvec, b;
	struct req_iterator iter;
	struct page *page;
	int ret = 0;

	page = alloc_page(GFP_NOIO);
	if (unlikely(!page))
		return -ENOMEM;

	rq_for_each_segment(bvec, rq, iter) {
		ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page,
			bvec.bv_offset, bvec.bv_len, pos >> 9);
		if (unlikely(ret))
			break;

		b.bv_page = page;
		b.bv_offset = 0;
		b.bv_len = bvec.bv_len;
		ret = lo_write_bvec(lo->lo_backing_file, &b, &pos);
		if (ret < 0)
			break;
	}

	__free_page(page);
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
87
56.13%
1
25.00%
Anton Altaparmakov
64
41.29%
1
25.00%
Andrew Morton
2
1.29%
1
25.00%
Linus Torvalds
2
1.29%
1
25.00%
Total
155
100.00%
4
100.00%



static int lo_read_simple(struct loop_device *lo, struct request *rq,
		loff_t pos)
{
	struct bio_vec bvec;
	struct req_iterator iter;
	struct iov_iter i;
	ssize_t len;

	rq_for_each_segment(bvec, rq, iter) {
		iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);
		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
		if (len < 0)
			return len;

		flush_dcache_page(bvec.bv_page);

		if (len != bvec.bv_len) {
			struct bio *bio;

			__rq_for_each_bio(bio, rq)
				zero_fill_bio(bio);
			break;
		}
		cond_resched();
	}

	return 0;
}

Contributors
Person
Tokens
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Commits
CommitProp
Christoph Hellwig
54
42.52%
2
22.22%
Andrew Morton
41
32.28%
2
22.22%
Linus Torvalds (pre-git)
10
7.87%
1
11.11%
Anton Altaparmakov
6
4.72%
1
11.11%
Kent Overstreet
6
4.72%
1
11.11%
Jens Axboe
5
3.94%
1
11.11%
Ming Lei
5
3.94%
1
11.11%
Total
127
100.00%
9
100.00%



static int lo_read_transfer(struct loop_device *lo, struct request *rq,
		loff_t pos)
{
	struct bio_vec bvec, b;
	struct req_iterator iter;
	struct iov_iter i;
	struct page *page;
	ssize_t len;
	int ret = 0;

	page = alloc_page(GFP_NOIO);
	if (unlikely(!page))
		return -ENOMEM;

	rq_for_each_segment(bvec, rq, iter) {
		loff_t offset = pos;

		b.bv_page = page;
		b.bv_offset = 0;
		b.bv_len = bvec.bv_len;

		iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);
		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
		if (len < 0) {
			ret = len;
			goto out_free_page;
		}

		ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page,
			bvec.bv_offset, len, offset >> 9);
		if (ret)
			goto out_free_page;

		flush_dcache_page(bvec.bv_page);

		if (len != bvec.bv_len) {
			struct bio *bio;

			__rq_for_each_bio(bio, rq)
				zero_fill_bio(bio);
			break;
		}
	}

	ret = 0;
out_free_page:
	__free_page(page);
	return ret;
}

Contributors
Person
Tokens
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CommitProp
Christoph Hellwig
139
60.17%
3
23.08%
Andrew Morton
22
9.52%
3
23.08%
Linus Torvalds (pre-git)
19
8.23%
1
7.69%
Dave Young
15
6.49%
1
7.69%
Jens Axboe
14
6.06%
1
7.69%
Ming Lei
11
4.76%
1
7.69%
Linus Torvalds
10
4.33%
2
15.38%
Kent Overstreet
1
0.43%
1
7.69%
Total
231
100.00%
13
100.00%



static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
{
	/*
         * We use punch hole to reclaim the free space used by the
         * image a.k.a. discard. However we do not support discard if
         * encryption is enabled, because it may give an attacker
         * useful information.
         */
	struct file *file = lo->lo_backing_file;
	int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
	int ret;

	if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) {
		ret = -EOPNOTSUPP;
		goto out;
	}

	ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
	if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
		ret = -EIO;
 out:
	return ret;
}

Contributors
Person
Tokens
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CommitProp
Lukas Czerner
80
72.07%
1
20.00%
Ming Lei
19
17.12%
2
40.00%
Linus Torvalds
9
8.11%
1
20.00%
Linus Torvalds (pre-git)
3
2.70%
1
20.00%
Total
111
100.00%
5
100.00%



static int lo_req_flush(struct loop_device *lo, struct request *rq)
{
	struct file *file = lo->lo_backing_file;
	int ret = vfs_fsync(file, 0);
	if (unlikely(ret && ret != -EINVAL))
		ret = -EIO;

	return ret;
}

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55
100.00%
1
100.00%
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55
100.00%
1
100.00%



static void lo_complete_rq(struct request *rq)
{
	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);

	if (unlikely(req_op(cmd->rq) == REQ_OP_READ && cmd->use_aio &&
		     cmd->ret >= 0 && cmd->ret < blk_rq_bytes(cmd->rq))) {
		struct bio *bio = cmd->rq->bio;

		bio_advance(bio, cmd->ret);
		zero_fill_bio(bio);
	}

	blk_mq_end_request(rq, cmd->ret < 0 ? BLK_STS_IOERR : BLK_STS_OK);
}

Contributors
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CommitProp
Christoph Hellwig
48
48.98%
2
50.00%
Ming Lei
46
46.94%
1
25.00%
Michael Christie
4
4.08%
1
25.00%
Total
98
100.00%
4
100.00%



static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
{
	if (!atomic_dec_and_test(&cmd->ref))
		return;
	kfree(cmd->bvec);
	cmd->bvec = NULL;
	blk_mq_complete_request(cmd->rq);
}

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Shaohua Li
43
100.00%
1
100.00%
Total
43
100.00%
1
100.00%



static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
{
	struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb);

	cmd->ret = ret;
	lo_rw_aio_do_completion(cmd);
}

Contributors
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Ming Lei
41
95.35%
1
33.33%
Shaohua Li
1
2.33%
1
33.33%
Christoph Hellwig
1
2.33%
1
33.33%
Total
43
100.00%
3
100.00%



static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
		     loff_t pos, bool rw)
{
	struct iov_iter iter;
	struct bio_vec *bvec;
	struct request *rq = cmd->rq;
	struct bio *bio = rq->bio;
	struct file *file = lo->lo_backing_file;
	unsigned int offset;
	int segments = 0;
	int ret;

	if (rq->bio != rq->biotail) {
		struct req_iterator iter;
		struct bio_vec tmp;

		__rq_for_each_bio(bio, rq)
			segments += bio_segments(bio);
		bvec = kmalloc(sizeof(struct bio_vec) * segments, GFP_NOIO);
		if (!bvec)
			return -EIO;
		cmd->bvec = bvec;

		/*
                 * The bios of the request may be started from the middle of
                 * the 'bvec' because of bio splitting, so we can't directly
                 * copy bio->bi_iov_vec to new bvec. The rq_for_each_segment
                 * API will take care of all details for us.
                 */
		rq_for_each_segment(tmp, rq, iter) {
			*bvec = tmp;
			bvec++;
		}
		bvec = cmd->bvec;
		offset = 0;
	} else {
		/*
                 * 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);
		segments = bio_segments(bio);
	}
	atomic_set(&cmd->ref, 2);

	iov_iter_bvec(&iter, ITER_BVEC | rw, bvec,
		      segments, 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;

	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)
		cmd->iocb.ki_complete(&cmd->iocb, ret, 0);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
186
56.53%
2
40.00%
Shaohua Li
137
41.64%
2
40.00%
Miklos Szeredi
6
1.82%
1
20.00%
Total
329
100.00%
5
100.00%



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_DISCARD:
	case REQ_OP_WRITE_ZEROES:
		return lo_discard(lo, rq, pos);
	case REQ_OP_WRITE:
		if (lo->transfer)
			return lo_write_transfer(lo, rq, pos);
		else 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 (lo->transfer)
			return lo_read_transfer(lo, rq, pos);
		else 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;
		break;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Christoph Hellwig
103
53.93%
3
27.27%
Ming Lei
64
33.51%
3
27.27%
Linus Torvalds
19
9.95%
2
18.18%
Michael Christie
5
2.62%
3
27.27%
Total
191
100.00%
11
100.00%



static inline void loop_update_dio(struct loop_device *lo)
{
	__loop_update_dio(lo, io_is_direct(lo->lo_backing_file) |
			lo->use_dio);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
28
100.00%
1
100.00%
Total
28
100.00%
1
100.00%



static void loop_reread_partitions(struct loop_device *lo,
				   struct block_device *bdev)
{
	int rc;

	/*
         * bd_mutex has been held already in release path, so don't
         * acquire it if this function is called in such case.
         *
         * If the reread partition isn't from release path, lo_refcnt
         * must be at least one and it can only become zero when the
         * current holder is released.
         */
	if (!atomic_read(&lo->lo_refcnt))
		rc = __blkdev_reread_part(bdev);
	else
		rc = blkdev_reread_part(bdev);
	if (rc)
		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
			__func__, lo->lo_number, lo->lo_file_name, rc);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
67
100.00%
1
100.00%
Total
67
100.00%
1
100.00%

/*
 * 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, *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;

	/* 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 */
	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);

	fput(old_file);
	if (lo->lo_flags & LO_FLAGS_PARTSCAN)
		loop_reread_partitions(lo, bdev);
	return 0;

 out_putf:
	fput(file);
 out:
	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
149
58.89%
2
22.22%
Omar Sandoval
59
23.32%
1
11.11%
Andrew Morton
19
7.51%
1
11.11%
Linus Torvalds
11
4.35%
1
11.11%
Lukas Czerner
7
2.77%
1
11.11%
Nicholas Piggin
5
1.98%
1
11.11%
Serge E. Hallyn
2
0.79%
1
11.11%
Linus Torvalds (pre-git)
1
0.40%
1
11.11%
Total
253
100.00%
9
100.00%



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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andrew Morton
22
52.38%
1
50.00%
Ming Lei
20
47.62%
1
50.00%
Total
42
100.00%
2
100.00%

/* 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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
40
71.43%
1
50.00%
Milan Broz
16
28.57%
1
50.00%
Total
56
100.00%
2
100.00%


#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, S_IRUGO, 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
70
62.50%
1
20.00%
Andrew Morton
37
33.04%
1
20.00%
Theodore Y. Ts'o
3
2.68%
1
20.00%
Milan Broz
1
0.89%
1
20.00%
Miklos Szeredi
1
0.89%
1
20.00%
Total
112
100.00%
5
100.00%



static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf)
{
	return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
22
68.75%
1
50.00%
Andrew Morton
10
31.25%
1
50.00%
Total
32
100.00%
2
100.00%



static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf)
{
	return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
29
90.62%
1
50.00%
Andrew Morton
3
9.38%
1
50.00%
Total
32
100.00%
2
100.00%



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");
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Milan Broz
22
55.00%
1
33.33%
Ming Lei
15
37.50%
1
33.33%
Andrew Morton
3
7.50%
1
33.33%
Total
40
100.00%
3
100.00%



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");
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Kay Sievers
40
100.00%
1
100.00%
Total
40
100.00%
1
100.00%



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");
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
40
100.00%
1
100.00%
Total
40
100.00%
1
100.00%


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 int loop_sysfs_init(struct loop_device *lo)
{
	return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
				  &loop_attribute_group);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Milan Broz
28
100.00%
1
100.00%
Total
28
100.00%
1
100.00%



static void loop_sysfs_exit(struct loop_device *lo)
{
	sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
			   &loop_attribute_group);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Milan Broz
27
100.00%
1
100.00%
Total
27
100.00%
1
100.00%



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;

	/*
         * We use punch hole to reclaim the free space used by the
         * image a.k.a. discard. However we do not support discard if
         * encryption is enabled, because it may give an attacker
         * useful information.
         */
	if ((!file->f_op->fallocate) ||
	    lo->lo_encrypt_key_size) {
		q->limits.discard_granularity = 0;
		q->limits.discard_alignment = 0;
		blk_queue_max_discard_sectors(q, 0);
		blk_queue_max_write_zeroes_sectors(q, 0);
		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
		return;
	}

	q->limits.discard_granularity = inode->i_sb->s_blocksize;
	q->limits.discard_alignment = 0;

	blk_queue_max_discard_sectors(q, UINT_MAX >> 9);
	blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);
	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Lukas Czerner
115
81.56%
2
33.33%
Christoph Hellwig
15
10.64%
1
16.67%
Jens Axboe
8
5.67%
1
16.67%
Omar Sandoval
2
1.42%
1
16.67%
Olaf Hering
1
0.71%
1
16.67%
Total
141
100.00%
6
100.00%



static void loop_unprepare_queue(struct loop_device *lo)
{
	kthread_flush_worker(&lo->worker);
	kthread_stop(lo->worker_task);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
25
96.15%
1
50.00%
Petr Mladek
1
3.85%
1
50.00%
Total
26
100.00%
2
100.00%



static int loop_kthread_worker_fn(void *worker_ptr)
{
	current->flags |= PF_LESS_THROTTLE;
	return kthread_worker_fn(worker_ptr);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Neil Brown
22
100.00%
1
100.00%
Total
22
100.00%
1
100.00%



static int loop_prepare_queue(struct loop_device *lo)
{
	kthread_init_worker(&lo->worker);
	lo->worker_task = kthread_run(loop_kthread_worker_fn,
			&lo->worker, "loop%d", lo->lo_number);
	if (IS_ERR(lo->worker_task))
		return -ENOMEM;
	set_user_nice(lo->worker_task, MIN_NICE);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
62
96.88%
1
33.33%
Neil Brown
1
1.56%
1
33.33%
Petr Mladek
1
1.56%
1
33.33%
Total
64
100.00%
3
100.00%



static int loop_set_fd(struct loop_device *lo, fmode_t mode,
		       struct block_device *bdev, unsigned int arg)
{
	struct file	*file, *f;
	struct inode	*inode;
	struct address_space *mapping;
	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_bdev == bdev)
			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;

	error = -EINVAL;
	if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
		goto out_putf;

	if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
	    !file->f_op->write_iter)
		lo_flags |= LO_FLAGS_READ_ONLY;

	error = -EFBIG;
	size = get_loop_size(lo, file);
	if ((loff_t)(sector_t)size != size)
		goto out_putf;
	error = loop_prepare_queue(lo);
	if (error)
		goto out_putf;

	error = 0;

	set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);

	lo->use_dio = false;
	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));

	if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
		blk_queue_write_cache(lo->lo_queue, true, false);

	loop_update_dio(lo);
	set_capacity(lo->lo_disk, size);
	bd_set_size(bdev, size << 9);
	loop_sysfs_init(lo);
	/* let user-space know about the new size */
	kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);

	set_blocksize(bdev, S_ISBLK(inode->i_mode) ?
		      block_size(inode->i_bdev) : PAGE_SIZE);

	lo->lo_state = Lo_bound;
	if (part_shift)
		lo->lo_flags |= LO_FLAGS_PARTSCAN;
	if (lo->lo_flags & LO_FLAGS_PARTSCAN)
		loop_reread_partitions(lo, bdev);

	/* Grab the block_device to prevent its destruction after we
         * put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev).
         */
	bdgrab(bdev);
	return 0;

 out_putf:
	fput(file);
 out:
	/* This is safe: open() is still holding a reference. */
	module_put(THIS_MODULE);
	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
115
22.59%
9
19.57%
Andrew Morton
97
19.06%
10
21.74%
Franz Pletz
84
16.50%
1
2.17%
Linus Torvalds
34
6.68%
1
2.17%
Ming Lei
29
5.70%
5
10.87%
Christoph Hellwig
23
4.52%
2
4.35%
Nikanth Karthikesan
22
4.32%
1
2.17%
David Zeuthen
16
3.14%
1
2.17%
Omar Sandoval
15
2.95%
1
2.17%
Kay Sievers
15
2.95%
1
2.17%
Anton Altaparmakov
12
2.36%
1
2.17%
Al Viro
11
2.16%
5
10.87%
Laurent Vivier
7
1.38%
1
2.17%
Andries E. Brouwer
6
1.18%
1
2.17%
Serge E. Hallyn
6
1.18%
1
2.17%
Anatol Pomozov
6
1.18%
1
2.17%
Milan Broz
5
0.98%
1
2.17%
Jens Axboe
4
0.79%
1
2.17%
Ken Chen
1
0.20%
1
2.17%
Akinobu Mita
1
0.20%
1
2.17%
Total
509
100.00%
46
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
50
73.53%
2
66.67%
Andries E. Brouwer
18
26.47%
1
33.33%
Total
68
100.00%
3
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
59
65.56%
2
50.00%
Andries E. Brouwer
31
34.44%
2
50.00%
Total
90
100.00%
4
100.00%



static int loop_clr_fd(struct loop_device *lo)
{
	struct file *filp = lo->lo_backing_file;
	gfp_t gfp = lo->old_gfp_mask;
	struct block_device *bdev = lo->lo_device;

	if (lo->lo_state != Lo_bound)
		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_ctl_mutex);
		return 0;
	}

	if (filp == NULL)
		return -EINVAL;

	/* freeze request queue during the transition */
	blk_mq_freeze_queue(lo->lo_queue);

	spin_lock_irq(&lo->lo_lock);
	lo->lo_state = Lo_rundown;
	lo->lo_backing_file = NULL;
	spin_unlock_irq(&lo->lo_lock);

	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;
	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);
	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);
	if (bdev) {
		bdput(bdev);
		invalidate_bdev(bdev);
	}
	set_capacity(lo->lo_disk, 0);
	loop_sysfs_exit(lo);
	if (bdev) {
		bd_set_size(bdev, 0);
		/* let user-space know about this change */
		kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
	}
	mapping_set_gfp_mask(filp->f_mapping, gfp);
	lo->lo_state = Lo_unbound;
	/* This is safe: open() is still holding a reference. */
	module_put(THIS_MODULE);
	blk_mq_unfreeze_queue(lo->lo_queue);

	if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
		loop_reread_partitions(lo, bdev);
	lo->lo_flags = 0;
	if (!part_shift)
		lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
	loop_unprepare_queue(lo);
	mutex_unlock(&lo->lo_ctl_mutex);
	/*
         * Need not hold lo_ctl_mutex to fput backing file.
         * Calling fput holding lo_ctl_mutex triggers a circular
         * lock dependency possibility warning as fput can take
         * bd_mutex which is usually taken before lo_ctl_mutex.
         */
	fput(filp);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
117
30.95%
8
21.05%
Linus Torvalds
39
10.32%
2
5.26%
Omar Sandoval
27
7.14%
2
5.26%
Ming Lei
27
7.14%
4
10.53%
Andries E. Brouwer
20
5.29%
3
7.89%
Phillip Susi
19
5.03%
1
2.63%
David Zeuthen
18
4.76%
1
2.63%
Al Viro
18
4.76%
4
10.53%
Dave Chinner
18
4.76%
1
2.63%
Andrew Morton
17
4.50%
4
10.53%
Jens Axboe
17
4.50%
1
2.63%
Kay Sievers
12
3.17%
2
5.26%
Ayan George
9
2.38%
1
2.63%
Nikanth Karthikesan
7
1.85%
1
2.63%
Anatol Pomozov
7
1.85%
1
2.63%
Milan Broz
5
1.32%
1
2.63%
Ken Chen
1
0.26%
1
2.63%
Total
378
100.00%
38
100.00%


static int

loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
{
	int err;
	struct loop_func_table *xfer;
	kuid_t uid = current_uid();

	if (lo->lo_encrypt_key_size &&
	    !uid_eq(lo->lo_key_owner, 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;

	/* I/O need to be drained during transfer transition */
	blk_mq_freeze_queue(lo->lo_queue);

	err = loop_release_xfer(lo);
	if (err)
		goto exit;

	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)
		goto exit;

	if (lo->lo_offset != info->lo_offset ||
	    lo->lo_sizelimit != info->lo_sizelimit) {
		if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) {
			err = -EFBIG;
			goto exit;
		}
	}

	loop_config_discard(lo);

	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;

	if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) !=
	     (info->lo_flags & LO_FLAGS_AUTOCLEAR))
		lo->lo_flags ^= LO_FLAGS_AUTOCLEAR;

	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 = uid;
	}

	/* update dio if lo_offset or transfer is changed */
	__loop_update_dio(lo, lo->use_dio);

 exit:
	blk_mq_unfreeze_queue(lo->lo_queue);

	if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) &&
	     !(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
		lo->lo_flags |= LO_FLAGS_PARTSCAN;
		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
		loop_reread_partitions(lo, lo->lo_device);
	}

	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
183
40.13%
7
30.43%
Andries E. Brouwer
121
26.54%
4
17.39%
Omar Sandoval
48
10.53%
1
4.35%
Lei Ming
31
6.80%
1
4.35%
David Woodhouse
24
5.26%
1
4.35%
Andrew Morton
11
2.41%
1
4.35%
Ming Lei
10
2.19%
1
4.35%
Dmitriy Monakhov
6
1.32%
1
4.35%
Eric W. Biedermann
6
1.32%
1
4.35%
Lukas Czerner
5
1.10%
1
4.35%
David Howells
5
1.10%
1
4.35%
Linus Torvalds
3
0.66%
1
4.35%
Arnd Bergmann
2
0.44%
1
4.35%
Hannes Reinecke
1
0.22%
1
4.35%
Total
456
100.00%
23
100.00%


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_path, &stat,
			    STATX_INO, AT_STATX_SYNC_AS_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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
124
53.45%
3
20.00%
Al Viro
46
19.83%
5
33.33%
Andries E. Brouwer
46
19.83%
4
26.67%
Linus Torvalds
11
4.74%
1
6.67%
David Howells
4
1.72%
1
6.67%
Josef 'Jeff' Sipek
1
0.43%
1
6.67%
Total
232
100.00%
15
100.00%


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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
153
86.93%
3
42.86%
Linus Torvalds (pre-git)
11
6.25%
2
28.57%
Linus Torvalds
9
5.11%
1
14.29%
Al Viro
3
1.70%
1
14.29%
Total
176
100.00%
7
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
212
100.00%
3
100.00%
Total
212
100.00%
3
100.00%


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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
63
98.44%
1
50.00%
Al Viro
1
1.56%
1
50.00%
Total
64
100.00%
2
100.00%


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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
50
98.04%
1
50.00%
Al Viro
1
1.96%
1
50.00%
Total
51
100.00%
2
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
96
98.97%
1
50.00%
Al Viro
1
1.03%
1
50.00%
Total
97
100.00%
2
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
76
98.70%
1
50.00%
Al Viro
1
1.30%
1
50.00%
Total
77
100.00%
2
100.00%



static int loop_set_capacity(struct loop_device *lo)
{
	if (unlikely(lo->lo_state != Lo_bound))
		return -ENXIO;

	return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Junjiro R. Okajima
27
67.50%
1
33.33%
Dmitriy Monakhov
8
20.00%
1
33.33%
Guo Chao
5
12.50%
1
33.33%
Total
40
100.00%
3
100.00%



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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
64
100.00%
1
100.00%
Total
64
100.00%
1
100.00%



static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
{
	if (lo->lo_state != Lo_bound)
		return -ENXIO;

	if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg))
		return -EINVAL;

	blk_mq_freeze_queue(lo->lo_queue);

	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);

	blk_mq_unfreeze_queue(lo->lo_queue);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Omar Sandoval
96
100.00%
2
100.00%
Total
96
100.00%
2
100.00%



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;
	int err;

	mutex_lock_nested(&lo->lo_ctl_mutex, 1);
	switch (cmd) {
	case LOOP_SET_FD:
		err = loop_set_fd(lo, mode, bdev, arg);
		break;
	case LOOP_CHANGE_FD:
		err = loop_change_fd(lo, bdev, arg);
		break;
	case LOOP_CLR_FD:
		/* loop_clr_fd would have unlocked lo_ctl_mutex on success */
		err = loop_clr_fd(lo);
		if (!err)
			goto out_unlocked;
		break;
	case LOOP_SET_STATUS:
		err = -EPERM;
		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
			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 = -EPERM;
		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
			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;
	case LOOP_SET_CAPACITY:
		err = -EPERM;
		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
			err = loop_set_capacity(lo);
		break;
	case LOOP_SET_DIRECT_IO:
		err = -EPERM;
		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
			err = loop_set_dio(lo, arg);
		break;
	case LOOP_SET_BLOCK_SIZE:
		err = -EPERM;
		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
			err = loop_set_block_size(lo, arg);
		break;
	default:
		err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
	}
	mutex_unlock(&lo->lo_ctl_mutex);

out_unlocked:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Andries E. Brouwer
134
39.30%
1
7.69%
Dmitriy Monakhov
36
10.56%
1
7.69%
Omar Sandoval
31
9.09%
1
7.69%
Ming Lei
31
9.09%
1
7.69%
Junjiro R. Okajima
29
8.50%
1
7.69%
Linus Torvalds (pre-git)
26
7.62%
2
15.38%
Nikanth Karthikesan
14
4.11%
1
7.69%
Andrew Morton
14
4.11%
1
7.69%
Linus Torvalds
13
3.81%
1
7.69%
Al Viro
12
3.52%
2
15.38%
Ingo Molnar
1
0.29%
1
7.69%
Total
341
100.00%
13
100.00%

#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_type;
	
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_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);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
David Howells
175
85.78%
1
20.00%
Linus Torvalds (pre-git)
18
8.82%
1
20.00%
Linus Torvalds
7
3.43%
1
20.00%
Al Viro
4
1.96%
2
40.00%
Total
204
100.00%
5
100.00%

/*
 * 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_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 ||
	    info.lo_init[0] != info64->lo_init[0] ||
	    info.lo_init[1] != info64->lo_init[1])
		return -EOVERFLOW;

	if (copy_to_user(arg, &info, sizeof(info)))
		return -EFAULT;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
154
58.11%
1
25.00%
David Howells
109
41.13%
1
25.00%
Linus Torvalds (pre-git)
2
0.75%
2
50.00%
Total
265
100.00%
4
100.00%


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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
53
100.00%
1
100.00%
Total
53
100.00%
1
100.00%


static int

loop_get_status_compat(struct loop_device *lo,
		       struct compat_loop_info __user *arg)
{
	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_compat(&info64, arg);
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
69
100.00%
1
100.00%
Total
69
100.00%
1
100.00%



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:
		mutex_lock(&lo->lo_ctl_mutex);
		err = loop_set_status_compat(
			lo, (const struct compat_loop_info __user *) arg);
		mutex_unlock(&lo->lo_ctl_mutex);
		break;
	case LOOP_GET_STATUS:
		mutex_lock(&lo->lo_ctl_mutex);
		err = loop_get_status_compat(
			lo, (struct compat_loop_info __user *) arg);
		mutex_unlock(&lo->lo_ctl_mutex);
		break;
	case LOOP_SET_CAPACITY:
	case LOOP_CLR_FD:
	case LOOP_GET_STATUS64:
	case LOOP_SET_STATUS64:
		arg = (unsigned long) compat_ptr(arg);
	case LOOP_SET_FD:
	case LOOP_CHANGE_FD:
		err = lo_ioctl(bdev, mode, cmd, arg);
		break;
	default:
		err = -ENOIOCTLCMD;
		break;
	}
	return err;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
143
86.14%
1
50.00%
David Howells
23
13.86%
1
50.00%
Total
166
100.00%
2
100.00%

#endif



static int lo_open(struct block_device *bdev, fmode_t mode)
{
	struct loop_device *lo;
	int err = 0;

	mutex_lock(&loop_index_mutex);
	lo = bdev->bd_disk->private_data;
	if (!lo) {
		err = -ENXIO;
		goto out;
	}

	atomic_inc(&lo->lo_refcnt);
out:
	mutex_unlock(&loop_index_mutex);
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
53
73.61%
2
66.67%
David Howells
19
26.39%
1
33.33%
Total
72
100.00%
3
100.00%



static void lo_release(struct gendisk *disk, fmode_t mode)
{
	struct loop_device *lo = disk->private_data;
	int err;

	if (atomic_dec_return(&lo->lo_refcnt))
		return;

	mutex_lock(&lo->lo_ctl_mutex);
	if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
		/*
                 * In autoclear mode, stop the loop thread
                 * and remove configuration after last close.
                 */
		err = loop_clr_fd(lo);
		if (!err)
			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);
	}

	mutex_unlock(&lo->lo_ctl_mutex);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
59
57.28%
2
50.00%
David Howells
25
24.27%
1
25.00%
Omar Sandoval
19
18.45%
1
25.00%
Total
103
100.00%
4
100.00%


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, S_IRUGO);
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
module_param(max_part, int, S_IRUGO);
MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
35
81.40%
1
50.00%
David Howells
8
18.60%
1
50.00%
Total
43
100.00%
2
100.00%



static int unregister_transfer_cb(int id, void *ptr, void *data)
{
	struct loop_device *lo = ptr;
	struct loop_func_table *xfer = data;

	mutex_lock(&lo->lo_ctl_mutex);
	if (lo->lo_encryption == xfer)
		loop_release_xfer(lo);
	mutex_unlock(&lo->lo_ctl_mutex);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
David Howells
38
60.32%
1
33.33%
Ming Lei
24
38.10%
1
33.33%
Al Viro
1
1.59%
1
33.33%
Total
63
100.00%
3
100.00%



int loop_unregister_transfer(int number)
{
	unsigned int n = number;
	struct loop_func_table *xfer;

	if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
		return -EINVAL;

	xfer_funcs[n] = NULL;
	idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
49
75.38%
1
25.00%
Kay Sievers
7
10.77%
1
25.00%
David Howells
7
10.77%
1
25.00%
Arnd Bergmann
2
3.08%
1
25.00%
Total
65
100.00%
4
100.00%


EXPORT_SYMBOL(loop_register_transfer);

EXPORT_SYMBOL(loop_unregister_transfer);



static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
		const struct blk_mq_queue_data *bd)
{
	struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
	struct loop_device *lo = cmd->rq->q->queuedata;

	blk_mq_start_request(bd->rq);

	if (lo->lo_state != Lo_bound)
		return BLK_STS_IOERR;

	switch (req_op(cmd->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;
	}

	kthread_queue_work(&lo->worker, &cmd->work);

	return BLK_STS_OK;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
64
56.64%
4
21.05%
Christoph Hellwig
21
18.58%
3
15.79%
Linus Torvalds (pre-git)
10
8.85%
1
5.26%
Michael Christie
5
4.42%
2
10.53%
Milan Broz
2
1.77%
1
5.26%
Andrew Morton
2
1.77%
1
5.26%
David Woodhouse
2
1.77%
1
5.26%
Al Viro
2
1.77%
1
5.26%
Linus Torvalds
1
0.88%
1
5.26%
Alexander Beregalov
1
0.88%
1
5.26%
Petr Mladek
1
0.88%
1
5.26%
David Howells
1
0.88%
1
5.26%
Arnd Bergmann
1
0.88%
1
5.26%
Total
113
100.00%
19
100.00%



static void loop_handle_cmd(struct loop_cmd *cmd)
{
	const bool write = op_is_write(req_op(cmd->rq));
	struct loop_device *lo = cmd->rq->q->queuedata;
	int ret = 0;

	if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) {
		ret = -EIO;
		goto failed;
	}

	ret = do_req_filebacked(lo, cmd->rq);
 failed:
	/* complete non-aio request */
	if (!cmd->use_aio || ret) {
		cmd->ret = ret ? -EIO : 0;
		blk_mq_complete_request(cmd->rq);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
67
62.04%
3
37.50%
Christoph Hellwig
24
22.22%
2
25.00%
Linus Torvalds (pre-git)
8
7.41%
1
12.50%
Michael Christie
6
5.56%
1
12.50%
Andries E. Brouwer
3
2.78%
1
12.50%
Total
108
100.00%
8
100.00%



static void loop_queue_work(struct kthread_work *work)
{
	struct loop_cmd *cmd =
		container_of(work, struct loop_cmd, work);

	loop_handle_cmd(cmd);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
26
83.87%
2
66.67%
Kay Sievers
5
16.13%
1
33.33%
Total
31
100.00%
3
100.00%



static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq,
		unsigned int hctx_idx, unsigned int numa_node)
{
	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);

	cmd->rq = rq;
	kthread_init_work(&cmd->work, loop_queue_work);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
30
56.60%
2
22.22%
Linus Torvalds (pre-git)
9
16.98%
2
22.22%
Andries E. Brouwer
7
13.21%
1
11.11%
Christoph Hellwig
3
5.66%
1
11.11%
Kay Sievers
2
3.77%
1
11.11%
Petr Mladek
1
1.89%
1
11.11%
Ken Chen
1
1.89%
1
11.11%
Total
53
100.00%
9
100.00%


static const struct blk_mq_ops loop_mq_ops = {
	.queue_rq       = loop_queue_rq,
	.init_request	= loop_init_request,
	.complete	= lo_complete_rq,
};



static int loop_add(struct loop_device **l, 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;

	/* 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);
	}
	if (err < 0)
		goto out_free_dev;
	i = err;

	err = -ENOMEM;
	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_SG_MERGE;
	lo->tag_set.driver_data = lo;

	err = blk_mq_alloc_tag_set(&lo->tag_set);
	if (err)
		goto out_free_idr;

	lo->lo_queue = blk_mq_init_queue(&lo->tag_set);
	if (IS_ERR_OR_NULL(lo->lo_queue)) {
		err = PTR_ERR(lo->lo_queue);
		goto out_cleanup_tags;
	}
	lo->lo_queue->queuedata = lo;

	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.
         */
	queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, lo->lo_queue);

	err = -ENOMEM;
	disk = lo->lo_disk = alloc_disk(1 << part_shift);
	if (!disk)
		goto out_free_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_SCAN;
	disk->flags |= GENHD_FL_EXT_DEVT;
	mutex_init(&lo->lo_ctl_mutex);
	atomic_set(&lo->lo_refcnt, 0);
	lo->lo_number		= i;
	spin_lock_init(&lo->lo_lock);
	disk->major		= LOOP_MAJOR;
	disk->first_minor	= i << part_shift;
	disk->fops		= &lo_fops;
	disk->private_data	= lo;
	disk->queue		= lo->lo_queue;
	sprintf(disk->disk_name, "loop%d", i);
	add_disk(disk);
	*l = lo;
	return lo->lo_number;

out_free_queue:
	blk_cleanup_queue(lo->lo_queue);
out_cleanup_tags:
	blk_mq_free_tag_set(&lo->tag_set);
out_free_idr:
	idr_remove(&loop_index_idr, i);
out_free_dev:
	kfree(lo);
out:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
125
27.41%
3
9.38%
Kay Sievers
90
19.74%
3
9.38%
Ken Chen
67
14.69%
1
3.12%
Al Viro
33
7.24%
5
15.62%
Linus Torvalds (pre-git)
31
6.80%
3
9.38%
Mikulas Patocka
30
6.58%
2
6.25%
Tejun Heo
21
4.61%
1
3.12%
Linus Torvalds
20
4.39%
3
9.38%
Shaohua Li
10
2.19%
2
6.25%
Minfei Huang
5
1.10%
1
3.12%
Silva Paulo
5
1.10%
1
3.12%
Wei Yongjun
5
1.10%
1
3.12%
Laurent Vivier
4
0.88%
1
3.12%
Andrew Morton
3
0.66%
1
3.12%
Serge E. Hallyn
3
0.66%
1
3.12%
Andries E. Brouwer
2
0.44%
1
3.12%
Ingo Molnar
1
0.22%
1
3.12%
Adrian Bunk
1
0.22%
1
3.12%
Total
456
100.00%
32
100.00%



static void loop_remove(struct loop_device *lo)
{
	blk_cleanup_queue(lo->lo_queue);
	del_gendisk(lo->lo_disk);
	blk_mq_free_tag_set(&lo->tag_set);
	put_disk(lo->lo_disk);
	kfree(lo);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ken Chen
27
60.00%
2
33.33%
Ming Lei
8
17.78%
1
16.67%
Neil Brown
4
8.89%
1
16.67%
Al Viro
3
6.67%
1
16.67%
Kay Sievers
3
6.67%
1
16.67%
Total
45
100.00%
6
100.00%



static int find_free_cb(int id, void *ptr, void *data)
{
	struct loop_device *lo = ptr;
	struct loop_device **l = data;

	if (lo->lo_state == Lo_unbound) {
		*l = lo;
		return 1;
	}
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Kay Sievers
30
56.60%
1
33.33%
Ken Chen
23
43.40%
2
66.67%
Total
53
100.00%
3
100.00%



static int loop_lookup(struct loop_device **l, int i)
{
	struct loop_device *lo;
	int ret = -ENODEV;

	if (i < 0) {
		int err;

		err = idr_for_each(&loop_index_idr, &find_free_cb, &lo);
		if (err == 1) {
			*l = lo;
			ret = lo->lo_number;
		}
		goto out;
	}

	/* lookup and return a specific i */
	lo = idr_find(&loop_index_idr, i);
	if (lo) {
		*l = lo;
		ret = lo->lo_number;
	}
out:
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Kay Sievers
69
65.09%
2
40.00%
Ken Chen
33
31.13%
2
40.00%
Al Viro
4
3.77%
1
20.00%
Total
106
100.00%
5
100.00%



static struct kobject *loop_probe(dev_t dev, int *part, void *data)
{
	struct loop_device *lo;
	struct kobject *kobj;
	int err;

	mutex_lock(&loop_index_mutex);
	err = loop_lookup(&lo, MINOR(dev) >> part_shift);
	if (err < 0)
		err = loop_add(&lo, MINOR(dev) >> part_shift);
	if (err < 0)
		kobj = NULL;
	else
		kobj = get_disk(lo->lo_disk);
	mutex_unlock(&loop_index_mutex);

	*part = 0;
	return kobj;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ken Chen
36
33.33%
1
11.11%
Kay Sievers
30
27.78%
1
11.11%
Al Viro
28
25.93%
2
22.22%
Namhyung Kim
10
9.26%
1
11.11%
Andrew Morton
1
0.93%
1
11.11%
Linus Torvalds (pre-git)
1
0.93%
1
11.11%
Mikulas Patocka
1
0.93%
1
11.11%
Linus Torvalds
1
0.93%
1
11.11%
Total
108
100.00%
9
100.00%



static long loop_control_ioctl(struct file *file, unsigned int cmd,
			       unsigned long parm)
{
	struct loop_device *lo;
	int ret = -ENOSYS;

	mutex_lock(&loop_index_mutex);
	switch (cmd) {
	case LOOP_CTL_ADD:
		ret = loop_lookup(&lo, parm);
		if (ret >= 0) {
			ret = -EEXIST;
			break;
		}
		ret = loop_add(&lo, parm);
		break;
	case LOOP_CTL_REMOVE:
		ret = loop_lookup(&lo, parm);
		if (ret < 0)
			break;
		mutex_lock(&lo->lo_ctl_mutex);
		if (lo->lo_state != Lo_unbound) {
			ret = -EBUSY;
			mutex_unlock(&lo->lo_ctl_mutex);
			break;
		}
		if (atomic_read(&lo->lo_refcnt) > 0) {
			ret = -EBUSY;
			mutex_unlock(&lo->lo_ctl_mutex);
			break;
		}
		lo->lo_disk->private_data = NULL;
		mutex_unlock(&lo->lo_ctl_mutex);
		idr_remove(&loop_index_idr, lo->lo_number);
		loop_remove(lo);
		break;
	case LOOP_CTL_GET_FREE:
		ret = loop_lookup(&lo, -1);
		if (ret >= 0)
			break;
		ret = loop_add(&lo, -1);
	}
	mutex_unlock(&loop_index_mutex);

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Kay Sievers
214
91.85%
1
20.00%
Ken Chen
9
3.86%
1
20.00%
Ming Lei
4
1.72%
1
20.00%
Linus Torvalds
3
1.29%
1
20.00%
Al Viro
3
1.29%
1
20.00%
Total
233
100.00%
5
100.00%


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;
	unsigned long range;
	struct loop_device *lo;
	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;
		range = max_loop << part_shift;
	} else {
		nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
		range = 1UL << MINORBITS;
	}

	err = misc_register(&loop_misc);
	if (err < 0)
		goto err_out;


	if (register_blkdev(LOOP_MAJOR, "loop")) {
		err = -EIO;
		goto misc_out;
	}

	blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
				  THIS_MODULE, loop_probe, NULL, NULL);

	/* pre-create number of devices given by config or max_loop */
	mutex_lock(&loop_index_mutex);
	for (i = 0; i < nr; i++)
		loop_add(&lo, i);
	mutex_unlock(&loop_index_mutex);

	printk(KERN_INFO "loop: module loaded\n");
	return 0;

misc_out:
	misc_deregister(&loop_misc);
err_out:
	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ken Chen
91
37.92%
2
13.33%
Kay Sievers
37
15.42%
3
20.00%
Guo Chao
33
13.75%
1
6.67%
Namhyung Kim
27
11.25%
3
20.00%
Anton Volkov
21
8.75%
1
6.67%
Laurent Vivier
21
8.75%
1
6.67%
Andrew Morton
5
2.08%
1
6.67%
Al Viro
4
1.67%
2
13.33%
Linus Torvalds
1
0.42%
1
6.67%
Total
240
100.00%
15
100.00%



static int loop_exit_cb(int id, void *ptr, void *data)
{
	struct loop_device *lo = ptr;

	loop_remove(lo);
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Kay Sievers
26
81.25%
1
16.67%
Ken Chen
3
9.38%
2
33.33%
Linus Torvalds (pre-git)
1
3.12%
1
16.67%
Andries E. Brouwer
1
3.12%
1
16.67%
Linus Torvalds
1
3.12%
1
16.67%
Total
32
100.00%
6
100.00%



static void __exit loop_exit(void)
{
	unsigned long range;

	range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;

	idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
	idr_destroy(&loop_index_idr);

	blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
	unregister_blkdev(LOOP_MAJOR, "loop");

	misc_deregister(&loop_misc);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ken Chen
26
38.81%
2
14.29%
Kay Sievers
17
25.37%
2
14.29%
Linus Torvalds (pre-git)
11
16.42%
2
14.29%
Al Viro
5
7.46%
2
14.29%
Namhyung Kim
2
2.99%
1
7.14%
Andrew Morton
2
2.99%
1
7.14%
Christoph Hellwig
1
1.49%
1
7.14%
Greg Kroah-Hartman
1
1.49%
1
7.14%
Linus Torvalds
1
1.49%
1
7.14%
Adrian Bunk
1
1.49%
1
7.14%
Total
67
100.00%
14
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
25
100.00%
1
100.00%
Total
25
100.00%
1
100.00%

__setup("max_loop=", max_loop_setup);
#endif
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
2436
25.33%
12
5.97%
Andries E. Brouwer
1069
11.12%
5
2.49%
Linus Torvalds (pre-git)
1066
11.09%
25
12.44%
Kay Sievers
682
7.09%
5
2.49%
Christoph Hellwig
625
6.50%
14
6.97%
David Howells
488
5.07%
3
1.49%
Andrew Morton
486
5.05%
23
11.44%
Ken Chen
326
3.39%
2
1.00%
Omar Sandoval
297
3.09%
6
2.99%
Linus Torvalds
217
2.26%
8
3.98%
Shaohua Li
213
2.22%
3
1.49%
Al Viro
212
2.20%
22
10.95%
Lukas Czerner
210
2.18%
3
1.49%
Anton Altaparmakov
187
1.94%
1
0.50%
Milan Broz
177
1.84%
3
1.49%
Dmitriy Monakhov
136
1.41%
1
0.50%
Guo Chao
89
0.93%
3
1.49%
Franz Pletz
84
0.87%
1
0.50%
Junjiro R. Okajima
56
0.58%
1
0.50%
Jens Axboe
51
0.53%
5
2.49%
Nikanth Karthikesan
43
0.45%
2
1.00%
Laurent Vivier
40
0.42%
1
0.50%
Namhyung Kim
39
0.41%
3
1.49%
David Zeuthen
34
0.35%
1
0.50%
Mikulas Patocka
31
0.32%
3
1.49%
Lei Ming
31
0.32%
1
0.50%
Neil Brown
27
0.28%
2
1.00%
David Woodhouse
26
0.27%
1
0.50%
Tejun Heo
21
0.22%
1
0.50%
Anton Volkov
21
0.22%
1
0.50%
Michael Christie
20
0.21%
3
1.49%
Phillip Susi
19
0.20%
1
0.50%
Dave Chinner
18
0.19%
1
0.50%
Dave Young
15
0.16%
1
0.50%
Serge E. Hallyn
14
0.15%
1
0.50%
Anatol Pomozov
13
0.14%
1
0.50%
Ayan George
9
0.09%
1
0.50%
Rusty Russell
8
0.08%
1
0.50%
Arnd Bergmann
8
0.08%
3
1.49%
Miklos Szeredi
7
0.07%
2
1.00%
Kent Overstreet
7
0.07%
1
0.50%
Nicholas Piggin
6
0.06%
2
1.00%
Eric W. Biedermann
6
0.06%
1
0.50%
Wei Yongjun
5
0.05%
1
0.50%
Silva Paulo
5
0.05%
1
0.50%
Minfei Huang
5
0.05%
1
0.50%
Petr Mladek
4
0.04%
1
0.50%
Pavel Machek
3
0.03%
1
0.50%
Theodore Y. Ts'o
3
0.03%
1
0.50%
Rafael J. Wysocki
3
0.03%
1
0.50%
Stephen Hemminger
3
0.03%
1
0.50%
Peter Zijlstra
2
0.02%
1
0.50%
Ingo Molnar
2
0.02%
1
0.50%
Adrian Bunk
2
0.02%
1
0.50%
Mike Galbraith
1
0.01%
1
0.50%
Akinobu Mita
1
0.01%
1
0.50%
Hannes Reinecke
1
0.01%
1
0.50%
Josef 'Jeff' Sipek
1
0.01%
1
0.50%
Greg Kroah-Hartman
1
0.01%
1
0.50%
Olaf Hering
1
0.01%
1
0.50%
Masahiro Yamada
1
0.01%
1
0.50%
Alexander Beregalov
1
0.01%
1
0.50%
Eric Biggers
1
0.01%
1
0.50%
Total
9616
100.00%
201
100.00%
Directory: drivers/block

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