| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Ming Lei | 2282 | 21.16% | 15 | 5.73% |
| Martijn Coenen | 876 | 8.12% | 15 | 5.73% |
| Andries E. Brouwer | 812 | 7.53% | 5 | 1.91% |
| Linus Torvalds (pre-git) | 769 | 7.13% | 25 | 9.54% |
| Jan Kara | 682 | 6.32% | 17 | 6.49% |
| Christoph Hellwig | 661 | 6.13% | 17 | 6.49% |
| Kay Sievers | 634 | 5.88% | 5 | 1.91% |
| David Howells | 457 | 4.24% | 3 | 1.15% |
| Andrew Morton | 359 | 3.33% | 20 | 7.63% |
| Omar Sandoval | 333 | 3.09% | 8 | 3.05% |
| Kenneth W Chen | 320 | 2.97% | 2 | 0.76% |
| Shaohua Li | 250 | 2.32% | 5 | 1.91% |
| Theodore Y. Ts'o | 191 | 1.77% | 2 | 0.76% |
| Anton Altaparmakov | 188 | 1.74% | 1 | 0.38% |
| Linus Torvalds | 187 | 1.73% | 9 | 3.44% |
| Milan Broz | 174 | 1.61% | 3 | 1.15% |
| Al Viro | 160 | 1.48% | 18 | 6.87% |
| Lukas Czerner | 158 | 1.47% | 3 | 1.15% |
| Jens Axboe | 157 | 1.46% | 7 | 2.67% |
| Jaegeuk Kim | 151 | 1.40% | 1 | 0.38% |
| Holger Hoffstätte | 95 | 0.88% | 1 | 0.38% |
| Dmitriy Monakhov | 88 | 0.82% | 1 | 0.38% |
| Evan Green | 84 | 0.78% | 3 | 1.15% |
| Guo Chao | 67 | 0.62% | 3 | 1.15% |
| Dongli Zhang | 44 | 0.41% | 3 | 1.15% |
| Namhyung Kim | 39 | 0.36% | 3 | 1.15% |
| Tetsuo Handa | 39 | 0.36% | 3 | 1.15% |
| Darrick J. Wong | 37 | 0.34% | 1 | 0.38% |
| Laurent Vivier | 36 | 0.33% | 1 | 0.38% |
| Mikulas Patocka | 33 | 0.31% | 4 | 1.53% |
| Nikanth Karthikesan | 29 | 0.27% | 2 | 0.76% |
| Junjiro R. Okajima | 27 | 0.25% | 1 | 0.38% |
| Neil Brown | 23 | 0.21% | 2 | 0.76% |
| David Zeuthen | 22 | 0.20% | 1 | 0.38% |
| Anton Volkov | 21 | 0.19% | 1 | 0.38% |
| Tejun Heo | 21 | 0.19% | 1 | 0.38% |
| Michael Christie | 19 | 0.18% | 3 | 1.15% |
| Lei Ming | 17 | 0.16% | 1 | 0.38% |
| Adam Manzanares | 16 | 0.15% | 1 | 0.38% |
| Dave Young | 15 | 0.14% | 1 | 0.38% |
| Serge E. Hallyn | 14 | 0.13% | 1 | 0.38% |
| Lennart Poettering | 13 | 0.12% | 1 | 0.38% |
| Luis R. Rodriguez | 12 | 0.11% | 1 | 0.38% |
| Anatol Pomozov | 12 | 0.11% | 1 | 0.38% |
| Ira Weiny | 12 | 0.11% | 1 | 0.38% |
| Jeff Layton | 10 | 0.09% | 1 | 0.38% |
| Dennis Zhou | 9 | 0.08% | 1 | 0.38% |
| Franz Pletz | 9 | 0.08% | 1 | 0.38% |
| Ayan George | 9 | 0.08% | 1 | 0.38% |
| David Woodhouse | 8 | 0.07% | 1 | 0.38% |
| Rusty Russell | 8 | 0.07% | 1 | 0.38% |
| Bart Van Assche | 7 | 0.06% | 2 | 0.76% |
| Miklos Szeredi | 7 | 0.06% | 2 | 0.76% |
| Kent Overstreet | 7 | 0.06% | 1 | 0.38% |
| Eric W. Biedermann | 6 | 0.06% | 1 | 0.38% |
| Arnd Bergmann | 6 | 0.06% | 2 | 0.76% |
| Silva Paulo | 5 | 0.05% | 1 | 0.38% |
| Wei Yongjun | 5 | 0.05% | 1 | 0.38% |
| Minfei Huang | 5 | 0.05% | 1 | 0.38% |
| Petr Mladek | 4 | 0.04% | 1 | 0.38% |
| Gustavo A. R. Silva | 4 | 0.04% | 1 | 0.38% |
| zhengbin | 4 | 0.04% | 1 | 0.38% |
| Alessio Balsini | 3 | 0.03% | 1 | 0.38% |
| Pavel Machek | 3 | 0.03% | 1 | 0.38% |
| Rafael J. Wysocki | 3 | 0.03% | 1 | 0.38% |
| Joe Perches | 3 | 0.03% | 1 | 0.38% |
| Phillip Susi | 3 | 0.03% | 1 | 0.38% |
| Stephen Hemminger | 3 | 0.03% | 1 | 0.38% |
| Nicholas Piggin | 3 | 0.03% | 2 | 0.76% |
| Kees Cook | 2 | 0.02% | 1 | 0.38% |
| Peter Zijlstra | 2 | 0.02% | 1 | 0.38% |
| Adrian Bunk | 2 | 0.02% | 1 | 0.38% |
| Mike Galbraith | 1 | 0.01% | 1 | 0.38% |
| Eric Biggers | 1 | 0.01% | 1 | 0.38% |
| Chengguang Xu | 1 | 0.01% | 1 | 0.38% |
| Alexander Beregalov | 1 | 0.01% | 1 | 0.38% |
| Olaf Hering | 1 | 0.01% | 1 | 0.38% |
| Masahiro Yamada | 1 | 0.01% | 1 | 0.38% |
| Greg Kroah-Hartman | 1 | 0.01% | 1 | 0.38% |
| Ross Zwisler | 1 | 0.01% | 1 | 0.38% |
| Total | 10784 | 262 |
/* * 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 <linux/ioprio.h> #include <linux/blk-cgroup.h> #include "loop.h" #include <linux/uaccess.h> static DEFINE_IDR(loop_index_idr); static DEFINE_MUTEX(loop_ctl_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; } 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; } 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; } static loff_t get_loop_size(struct loop_device *lo, struct file *file) { return get_size(lo->lo_offset, lo->lo_sizelimit, file); } 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) */ if (lo->lo_state == Lo_bound) blk_mq_freeze_queue(lo->lo_queue); lo->use_dio = use_dio; if (use_dio) { blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue); lo->lo_flags |= LO_FLAGS_DIRECT_IO; } else { blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); lo->lo_flags &= ~LO_FLAGS_DIRECT_IO; } if (lo->lo_state == Lo_bound) blk_mq_unfreeze_queue(lo->lo_queue); } /** * loop_validate_block_size() - validates the passed in block size * @bsize: size to validate */ static int loop_validate_block_size(unsigned short bsize) { if (bsize < 512 || bsize > PAGE_SIZE || !is_power_of_2(bsize)) return -EINVAL; return 0; } /** * loop_set_size() - sets device size and notifies userspace * @lo: struct loop_device to set the size for * @size: new size of the loop device * * Callers must validate that the size passed into this function fits into * a sector_t, eg using loop_validate_size() */ static void loop_set_size(struct loop_device *lo, loff_t size) { struct block_device *bdev = lo->lo_device; bd_set_size(bdev, size << SECTOR_SHIFT); set_capacity_revalidate_and_notify(lo->lo_disk, size, false); } 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; } 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, WRITE, 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; } 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; } /* * 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; } 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, READ, &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; } 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, READ, &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; } static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos, int mode) { /* * We use fallocate to manipulate the space mappings used by the image * a.k.a. discard/zerorange. However we do not support this if * encryption is enabled, because it may give an attacker useful * information. */ struct file *file = lo->lo_backing_file; struct request_queue *q = lo->lo_queue; int ret; mode |= FALLOC_FL_KEEP_SIZE; if (!blk_queue_discard(q)) { 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; } 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; } static void lo_complete_rq(struct request *rq) { struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); blk_status_t ret = BLK_STS_OK; if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || req_op(rq) != REQ_OP_READ) { if (cmd->ret < 0) ret = errno_to_blk_status(cmd->ret); goto end_io; } /* * Short READ - if we got some data, advance our request and * retry it. If we got no data, end the rest with EIO. */ if (cmd->ret) { blk_update_request(rq, BLK_STS_OK, cmd->ret); cmd->ret = 0; blk_mq_requeue_request(rq, true); } else { if (cmd->use_aio) { struct bio *bio = rq->bio; while (bio) { zero_fill_bio(bio); bio = bio->bi_next; } } ret = BLK_STS_IOERR; end_io: blk_mq_end_request(rq, ret); } } static void lo_rw_aio_do_completion(struct loop_cmd *cmd) { struct request *rq = blk_mq_rq_from_pdu(cmd); if (!atomic_dec_and_test(&cmd->ref)) return; kfree(cmd->bvec); cmd->bvec = NULL; if (likely(!blk_should_fake_timeout(rq->q))) blk_mq_complete_request(rq); } static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) { struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); if (cmd->css) css_put(cmd->css); cmd->ret = ret; lo_rw_aio_do_completion(cmd); } static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos, bool rw) { struct iov_iter iter; struct req_iterator rq_iter; struct bio_vec *bvec; struct request *rq = blk_mq_rq_from_pdu(cmd); struct bio *bio = rq->bio; struct file *file = lo->lo_backing_file; struct bio_vec tmp; unsigned int offset; int nr_bvec = 0; int ret; rq_for_each_bvec(tmp, rq, rq_iter) nr_bvec++; if (rq->bio != rq->biotail) { bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), 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_bvec * API will take care of all details for us. */ rq_for_each_bvec(tmp, rq, 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); } 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 (cmd->css) kthread_associate_blkcg(cmd->css); 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); kthread_associate_blkcg(NULL); if (ret != -EIOCBQUEUED) cmd->iocb.ki_complete(&cmd->iocb, ret, 0); 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 (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; } } 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, struct block_device *bdev) { int rc; mutex_lock(&bdev->bd_mutex); rc = bdev_disk_changed(bdev, false); mutex_unlock(&bdev->bd_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) && MAJOR(i->i_rdev) == 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; if (f->f_mapping->host->i_bdev == bdev) return -EBADF; l = f->f_mapping->host->i_bdev->bd_disk->private_data; if (l->lo_state != Lo_bound) { return -EINVAL; } 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 = NULL, *old_file; int error; bool partscan; error = mutex_lock_killable(&loop_ctl_mutex); if (error) return error; 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 = -EBADF; file = fget(arg); if (!file) 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 */ 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; mutex_unlock(&loop_ctl_mutex); /* * We must drop file reference outside of loop_ctl_mutex as dropping * the file ref can take bd_mutex which creates circular locking * dependency. */ fput(old_file); if (partscan) loop_reread_partitions(lo, bdev); return 0; out_err: mutex_unlock(&loop_ctl_mutex); if (file) 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) && !lo->lo_encrypt_key_size) { struct request_queue *backingq; backingq = bdev_get_queue(inode->i_bdev); 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. However we do not support discard if * encryption is enabled, because it may give an attacker * useful information. */ } else if (!file->f_op->fallocate || lo->lo_encrypt_key_size) { 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; } static void loop_unprepare_queue(struct loop_device *lo) { kthread_flush_worker(&lo->worker); kthread_stop(lo->worker_task); } static int loop_kthread_worker_fn(void *worker_ptr) { current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; return kthread_worker_fn(worker_ptr); } 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; } 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); } static int loop_release_xfer(struct loop_device *lo) { int err = 0; struct loop_func_table *xfer = lo->lo_encryption; if (xfer) { if (xfer->release) err = xfer->release(lo); lo->transfer = NULL; lo->lo_encryption = NULL; module_put(xfer->owner); } return err; } static int loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, const struct loop_info64 *i) { int err = 0; if (xfer) { struct module *owner = xfer->owner; if (!try_module_get(owner)) return -EINVAL; if (xfer->init) err = xfer->init(lo, i); if (err) module_put(owner); else lo->lo_encryption = xfer; } return err; } /** * 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) { int err; struct loop_func_table *xfer; kuid_t uid = current_uid(); if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) return -EINVAL; err = loop_release_xfer(lo); if (err) return err; if (info->lo_encrypt_type) { unsigned int type = info->lo_encrypt_type; if (type >= MAX_LO_CRYPT) return -EINVAL; xfer = xfer_funcs[type]; if (xfer == NULL) return -EINVAL; } else xfer = NULL; err = loop_init_xfer(lo, xfer, info); if (err) return err; lo->lo_offset = info->lo_offset; lo->lo_sizelimit = info->lo_sizelimit; memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); lo->lo_file_name[LO_NAME_SIZE-1] = 0; lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; if (!xfer) xfer = &none_funcs; lo->transfer = xfer->transfer; lo->ioctl = xfer->ioctl; lo->lo_flags = info->lo_flags; 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; } 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; struct inode *inode; struct address_space *mapping; struct block_device *claimed_bdev = NULL; int error; loff_t size; bool partscan; unsigned short bsize; /* This is safe, since we have a reference from open(). */ __module_get(THIS_MODULE); error = -EBADF; file = fget(config->fd); if (!file) goto out; /* * 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)) { claimed_bdev = bdev->bd_contains; error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure); if (error) goto out_putf; } error = mutex_lock_killable(&loop_ctl_mutex); 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 = loop_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; error = loop_prepare_queue(lo); if (error) goto out_unlock; set_device_ro(bdev, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0); 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_update_rotational(lo); loop_update_dio(lo); loop_sysfs_init(lo); size = get_loop_size(lo, file); loop_set_size(lo, size); 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; partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; if (partscan) lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; /* Grab the block_device to prevent its destruction after we * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev). */ bdgrab(bdev); mutex_unlock(&loop_ctl_mutex); if (partscan) loop_reread_partitions(lo, bdev); if (claimed_bdev) bd_abort_claiming(bdev, claimed_bdev, loop_configure); return 0; out_unlock: mutex_unlock(&loop_ctl_mutex); out_bdev: if (claimed_bdev) bd_abort_claiming(bdev, claimed_bdev, loop_configure); out_putf: fput(file); out: /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); return error; } static int __loop_clr_fd(struct loop_device *lo, bool release) { struct file *filp = NULL; gfp_t gfp = lo->old_gfp_mask; struct block_device *bdev = lo->lo_device; int err = 0; bool partscan = false; int lo_number; mutex_lock(&loop_ctl_mutex); if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) { err = -ENXIO; goto out_unlock; } filp = lo->lo_backing_file; if (filp == NULL) { err = -EINVAL; goto out_unlock; } /* freeze request queue during the transition */ blk_mq_freeze_queue(lo->lo_queue); spin_lock_irq(&lo->lo_lock); 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); bdev->bd_inode->i_mapping->wb_err = 0; } 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); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); blk_mq_unfreeze_queue(lo->lo_queue); partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev; lo_number = lo->lo_number; loop_unprepare_queue(lo); out_unlock: mutex_unlock(&loop_ctl_mutex); if (partscan) { /* * 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 (!release) mutex_lock(&bdev->bd_mutex); err = bdev_disk_changed(bdev, false); if (!release) mutex_unlock(&bdev->bd_mutex); if (err) pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", __func__, lo_number, err); /* Device is gone, no point in returning error */ err = 0; } /* * lo->lo_state is set to Lo_unbound here after above partscan has * finished. * * There cannot be anybody else entering __loop_clr_fd() as * lo->lo_backing_file is already cleared and Lo_rundown state * protects us from all the other places trying to change the 'lo' * device. */ mutex_lock(&loop_ctl_mutex); lo->lo_flags = 0; if (!part_shift) lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; lo->lo_state = Lo_unbound; mutex_unlock(&loop_ctl_mutex); /* * Need not hold loop_ctl_mutex to fput backing file. * Calling fput holding loop_ctl_mutex triggers a circular * lock dependency possibility warning as fput can take * bd_mutex which is usually taken before loop_ctl_mutex. */ if (filp) fput(filp); return err; } static int loop_clr_fd(struct loop_device *lo) { int err; err = mutex_lock_killable(&loop_ctl_mutex); if (err) return err; if (lo->lo_state != Lo_bound) { mutex_unlock(&loop_ctl_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(&loop_ctl_mutex); return 0; } lo->lo_state = Lo_rundown; mutex_unlock(&loop_ctl_mutex); return __loop_clr_fd(lo, false); } static int loop_set_status(struct loop_device *lo, const struct loop_info64 *info) { int err; struct block_device *bdev; kuid_t uid = current_uid(); int prev_lo_flags; bool partscan = false; bool size_changed = false; err = mutex_lock_killable(&loop_ctl_mutex); if (err) return err; if (lo->lo_encrypt_key_size && !uid_eq(lo->lo_key_owner, uid) && !capable(CAP_SYS_ADMIN)) { err = -EPERM; goto out_unlock; } 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_SCAN; bdev = lo->lo_device; partscan = true; } out_unlock: mutex_unlock(&loop_ctl_mutex); if (partscan) loop_reread_partitions(lo, bdev); 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(&loop_ctl_mutex); if (ret) return ret; if (lo->lo_state != Lo_bound) { mutex_unlock(&loop_ctl_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); 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); } /* Drop loop_ctl_mutex while we call into the filesystem. */ path = lo->lo_backing_file->f_path; path_get(&path); mutex_unlock(&loop_ctl_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_encrypt_type = info->lo_encrypt_type; info64->lo_encrypt_key_size = info->lo_encrypt_key_size; info64->lo_flags = info->lo_flags; info64->lo_init[0] = info->lo_init[0]; info64->lo_init[1] = info->lo_init[1]; if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); else memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); } static int loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) { memset(info, 0, sizeof(*info)); info->lo_number = info64->lo_number; info->lo_device = info64->lo_device; info->lo_inode = info64->lo_inode; info->lo_rdevice = info64->lo_rdevice; info->lo_offset = info64->lo_offset; info->lo_encrypt_type = info64->lo_encrypt_type; info->lo_encrypt_key_size = info64->lo_encrypt_key_size; info->lo_flags = info64->lo_flags; info->lo_init[0] = info64->lo_init[0]; info->lo_init[1] = info64->lo_init[1]; if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); else memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); /* error in case values were truncated */ if (info->lo_device != info64->lo_device || info->lo_rdevice != info64->lo_rdevice || info->lo_inode != info64->lo_inode || info->lo_offset != info64->lo_offset) return -EOVERFLOW; return 0; } static int loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) { struct loop_info info; struct loop_info64 info64; if (copy_from_user(&info, arg, sizeof (struct loop_info))) return -EFAULT; loop_info64_from_old(&info, &info64); return loop_set_status(lo, &info64); } static int loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) { struct loop_info64 info64; if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) return -EFAULT; return loop_set_status(lo, &info64); } static int loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { struct loop_info info; struct loop_info64 info64; int err; 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 = loop_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(&loop_ctl_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 = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } mutex_unlock(&loop_ctl_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_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; } /* * 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; } 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; int err; err = mutex_lock_killable(&loop_ctl_mutex); if (err) return err; lo = bdev->bd_disk->private_data; if (!lo) { err = -ENXIO; goto out; } atomic_inc(&lo->lo_refcnt); out: mutex_unlock(&loop_ctl_mutex); return err; } static void lo_release(struct gendisk *disk, fmode_t mode) { struct loop_device *lo; mutex_lock(&loop_ctl_mutex); lo = disk->private_data; 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(&loop_ctl_mutex); /* * In autoclear mode, stop the loop thread * and remove configuration after last close. */ __loop_clr_fd(lo, true); 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(&loop_ctl_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); 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; } static int unregister_transfer_cb(int id, void *ptr, void *data) { struct loop_device *lo = ptr; struct loop_func_table *xfer = data; mutex_lock(&loop_ctl_mutex); if (lo->lo_encryption == xfer) loop_release_xfer(lo); mutex_unlock(&loop_ctl_mutex); return 0; } 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; } 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 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 */ #ifdef CONFIG_BLK_CGROUP if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { cmd->css = &bio_blkcg(rq->bio)->css; css_get(cmd->css); } else #endif cmd->css = NULL; kthread_queue_work(&lo->worker, &cmd->work); 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; if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { ret = -EIO; goto failed; } ret = do_req_filebacked(lo, rq); 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_queue_work(struct kthread_work *work) { struct loop_cmd *cmd = container_of(work, struct loop_cmd, work); loop_handle_cmd(cmd); } 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); kthread_init_work(&cmd->work, loop_queue_work); return 0; } 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_STACKING; 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(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. */ blk_queue_flag_set(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; 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; } static void loop_remove(struct loop_device *lo) { del_gendisk(lo->lo_disk); blk_cleanup_queue(lo->lo_queue); blk_mq_free_tag_set(&lo->tag_set); put_disk(lo->lo_disk); kfree(lo); } 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; } 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; } static struct kobject *loop_probe(dev_t dev, int *part, void *data) { struct loop_device *lo; struct kobject *kobj; int err; mutex_lock(&loop_ctl_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_and_module(lo->lo_disk); mutex_unlock(&loop_ctl_mutex); *part = 0; return kobj; } static long loop_control_ioctl(struct file *file, unsigned int cmd, unsigned long parm) { struct loop_device *lo; int ret; ret = mutex_lock_killable(&loop_ctl_mutex); if (ret) return ret; ret = -ENOSYS; 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; if (lo->lo_state != Lo_unbound) { ret = -EBUSY; break; } if (atomic_read(&lo->lo_refcnt) > 0) { ret = -EBUSY; break; } lo->lo_disk->private_data = NULL; 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_ctl_mutex); return ret; } 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_ctl_mutex); for (i = 0; i < nr; i++) loop_add(&lo, i); mutex_unlock(&loop_ctl_mutex); printk(KERN_INFO "loop: module loaded\n"); return 0; misc_out: misc_deregister(&loop_misc); err_out: return err; } static int loop_exit_cb(int id, void *ptr, void *data) { struct loop_device *lo = ptr; loop_remove(lo); return 0; } static void __exit loop_exit(void) { unsigned long range; range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; mutex_lock(&loop_ctl_mutex); 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); mutex_unlock(&loop_ctl_mutex); } module_init(loop_init); module_exit(loop_exit); #ifndef MODULE static int __init max_loop_setup(char *str) { max_loop = simple_strtol(str, NULL, 0); return 1; } __setup("max_loop=", max_loop_setup); #endif
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