// SPDX-License-Identifier: GPL-2.0 /* * xloop_main.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_xloop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997 * * Added devfs support - Richard Gooch 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 xloop devices now dynamic via max_xloop module parameter. * Russell Kroll 19990701 * * Maximum number of xloop devices when compiled-in now selectable by passing * max_xloop=<1-255> to the kernel on boot. * Erik I. Bolsø, , 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 , Nov 2000 * * Support up to 256 xloop devices * Heinz Mauelshagen , 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 * * Support for using file formats. * Manuel Bentele , 2019 * * Still To Fix: * - Advisory locking is ignored here. * - Should use an own CAP_* category instead of CAP_SYS_ADMIN * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_DEBUG_FS #include #endif #include #include "xloop_file_fmt.h" #include "xloop_main.h" #include #define XLOOP_IDLE_WORKER_TIMEOUT (60 * HZ) #if LINUX_VERSION_CODE < KERNEL_VERSION(5, 15, 132) || \ (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 16, 0) && LINUX_VERSION_CODE < KERNEL_VERSION(5, 17, 0)) #define GENHD_FL_NO_PART GENHD_FL_NO_PART_SCAN #endif static DEFINE_IDR(xloop_index_idr); static DEFINE_MUTEX(xloop_ctl_mutex); static DEFINE_MUTEX(xloop_validate_mutex); /** * xloop_global_lock_killable() - take locks for safe xloop_validate_file() test * * @xlo: struct xloop_device * @global: true if @xlo is about to bind another "struct xloop_device", false otherwise * * Returns 0 on success, -EINTR otherwise. * * Since xloop_validate_file() traverses on other "struct xloop_device" if * is_xloop_device() is true, we need a global lock for serializing concurrent * xloop_configure()/xloop_change_fd()/__xloop_clr_fd() calls. */ static int xloop_global_lock_killable(struct xloop_device *xlo, bool global) { int err; if (global) { err = mutex_lock_killable(&xloop_validate_mutex); if (err) return err; } err = mutex_lock_killable(&xlo->xlo_mutex); if (err && global) mutex_unlock(&xloop_validate_mutex); return err; } /** * xloop_global_unlock() - release locks taken by xloop_global_lock_killable() * * @xlo: struct xloop_device * @global: true if @xlo was about to bind another "struct xloop_device", false otherwise */ static void xloop_global_unlock(struct xloop_device *xlo, bool global) { mutex_unlock(&xlo->xlo_mutex); if (global) mutex_unlock(&xloop_validate_mutex); } static int max_part; static int part_shift; struct device *xloop_device_to_dev(struct xloop_device *xlo) { return disk_to_dev(xlo->xlo_disk); } EXPORT_SYMBOL(xloop_device_to_dev); static int transfer_xor(struct xloop_device *xlo, int cmd, struct page *raw_page, unsigned raw_off, struct page *xloop_page, unsigned xloop_off, int size, sector_t real_block) { char *raw_buf = kmap_atomic(raw_page) + raw_off; char *xloop_buf = kmap_atomic(xloop_page) + xloop_off; char *in, *out, *key; int i, keysize; if (cmd == READ) { in = raw_buf; out = xloop_buf; } else { in = xloop_buf; out = raw_buf; } key = xlo->xlo_encrypt_key; keysize = xlo->xlo_encrypt_key_size; for (i = 0; i < size; i++) *out++ = *in++ ^ key[(i & 511) % keysize]; kunmap_atomic(xloop_buf); kunmap_atomic(raw_buf); cond_resched(); return 0; } static int xor_init(struct xloop_device *xlo, const struct xloop_info64 *info) { if (unlikely(info->xlo_encrypt_key_size <= 0)) return -EINVAL; return 0; } static struct xloop_func_table none_funcs = { .number = XLO_CRYPT_NONE, }; static struct xloop_func_table xor_funcs = { .number = XLO_CRYPT_XOR, .transfer = transfer_xor, .init = xor_init }; /* xfer_funcs[0] is special - its release function is never called */ static struct xloop_func_table *xfer_funcs[MAX_XLO_CRYPT] = { &none_funcs, &xor_funcs }; static loff_t get_xloop_size(struct xloop_device *xlo, struct file *file) { return xloop_file_fmt_sector_size(xlo->xlo_fmt, file, xlo->xlo_offset, xlo->xlo_sizelimit); } static void __xloop_update_dio(struct xloop_device *xlo, bool dio) { struct file *file = xlo->xlo_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 xlo_offset is aligned with the * logical I/O size of backing device, and the logical block * size of xloop is bigger than the backing device's and the xloop * 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(xlo->xlo_queue) >= sb_bsize && !(xlo->xlo_offset & dio_align) && mapping->a_ops->direct_IO && !xlo->transfer) use_dio = true; else use_dio = false; } else { use_dio = false; } if (xlo->use_dio == use_dio) return; /* flush dirty pages before changing direct IO */ xloop_file_fmt_flush(xlo->xlo_fmt); /* * The flag of XLO_FLAGS_DIRECT_IO is handled similarly with * XLO_FLAGS_READ_ONLY, both are set from kernel, and xlosetup * will get updated by ioctl(XLOOP_GET_STATUS) */ if (xlo->xlo_state == Xlo_bound) blk_mq_freeze_queue(xlo->xlo_queue); xlo->use_dio = use_dio; if (use_dio) { blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, xlo->xlo_queue); xlo->xlo_flags |= XLO_FLAGS_DIRECT_IO; } else { blk_queue_flag_set(QUEUE_FLAG_NOMERGES, xlo->xlo_queue); xlo->xlo_flags &= ~XLO_FLAGS_DIRECT_IO; } if (xlo->xlo_state == Xlo_bound) blk_mq_unfreeze_queue(xlo->xlo_queue); } /** * xloop_set_size() - sets device size and notifies userspace * @xlo: struct xloop_device to set the size for * @size: new size of the xloop device * * Callers must validate that the size passed into this function fits into * a sector_t, eg using xloop_validate_size() */ static void xloop_set_size(struct xloop_device *xlo, loff_t size) { if (!set_capacity_and_notify(xlo->xlo_disk, size)) kobject_uevent(&disk_to_dev(xlo->xlo_disk)->kobj, KOBJ_CHANGE); } static inline int xlo_do_transfer(struct xloop_device *xlo, int cmd, struct page *rpage, unsigned roffs, struct page *lpage, unsigned loffs, int size, sector_t rblock) { int ret; ret = xlo->transfer(xlo, cmd, rpage, roffs, lpage, loffs, size, rblock); if (likely(!ret)) return 0; pr_err_ratelimited("Transfer error at byte offset %llu, length %i.\n", (unsigned long long)rblock << 9, size); return ret; } static void xlo_complete_rq(struct request *rq) { struct xloop_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 int do_req_filebacked(struct xloop_device *xlo, struct request *rq) { struct xloop_cmd *cmd = blk_mq_rq_to_pdu(rq); /* * xlo_write_simple and xlo_read_simple should have been covered * by io submit style function like xloop_file_fmt_read_aio(), one * blocker is that xloop_file_fmt_read() 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 xloop_file_fmt_flush(xlo->xlo_fmt); case REQ_OP_WRITE_ZEROES: return xloop_file_fmt_write_zeros(xlo->xlo_fmt, rq); case REQ_OP_DISCARD: return xloop_file_fmt_discard(xlo->xlo_fmt, rq); case REQ_OP_WRITE: if (cmd->use_aio) return xloop_file_fmt_write_aio(xlo->xlo_fmt, rq); else return xloop_file_fmt_write(xlo->xlo_fmt, rq); case REQ_OP_READ: if (cmd->use_aio) return xloop_file_fmt_read_aio(xlo->xlo_fmt, rq); else return xloop_file_fmt_read(xlo->xlo_fmt, rq); default: WARN_ON_ONCE(1); return -EIO; } } static inline void xloop_update_dio(struct xloop_device *xlo) { __xloop_update_dio(xlo, (xlo->xlo_backing_file->f_flags & O_DIRECT) | xlo->use_dio); } static void xloop_reread_partitions(struct xloop_device *xlo) { int rc; mutex_lock(&xlo->xlo_disk->open_mutex); rc = bdev_disk_changed(xlo->xlo_disk, false); mutex_unlock(&xlo->xlo_disk->open_mutex); if (rc) dev_warn(xloop_device_to_dev(xlo), "partition scan of xloop%d (%s) failed (rc=%d)\n", xlo->xlo_number, xlo->xlo_file_name, rc); } static inline int is_xloop_device(struct file *file) { struct inode *i = file->f_mapping->host; return i && S_ISBLK(i->i_mode) && imajor(i) == XLOOP_MAJOR; } static int xloop_validate_file(struct file *file, struct block_device *bdev) { struct inode *inode = file->f_mapping->host; struct file *f = file; /* Avoid recursion */ while (is_xloop_device(f)) { struct xloop_device *l; lockdep_assert_held(&xloop_validate_mutex); if (f->f_mapping->host->i_rdev == bdev->bd_dev) return -EBADF; l = I_BDEV(f->f_mapping->host)->bd_disk->private_data; if (l->xlo_state != Xlo_bound) return -EINVAL; /* Order wrt setting xlo->xlo_backing_file in xloop_configure(). */ rmb(); f = l->xlo_backing_file; } if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) return -EINVAL; return 0; } /* * xloop_change_fd switched the backing store of a xloopback 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 xloop device is used read-only, and if the * new backing store is the same size and type as the old backing store. */ static int xloop_change_fd(struct xloop_device *xlo, struct block_device *bdev, unsigned int arg) { struct file *file = fget(arg); struct file *old_file; int error; bool partscan; bool is_xloop; if (!file) return -EBADF; is_xloop = is_xloop_device(file); error = xloop_global_lock_killable(xlo, is_xloop); if (error) goto out_putf; error = -ENXIO; if (xlo->xlo_state != Xlo_bound) goto out_err; /* the xloop device has to be read-only */ error = -EINVAL; if (!(xlo->xlo_flags & XLO_FLAGS_READ_ONLY)) goto out_err; error = xloop_validate_file(file, bdev); if (error) goto out_err; old_file = xlo->xlo_backing_file; error = -EINVAL; /* size of the new backing store needs to be the same */ if (get_xloop_size(xlo, file) != get_xloop_size(xlo, old_file)) goto out_err; /* and ... switch */ disk_force_media_change(xlo->xlo_disk, DISK_EVENT_MEDIA_CHANGE); blk_mq_freeze_queue(xlo->xlo_queue); mapping_set_gfp_mask(old_file->f_mapping, xlo->old_gfp_mask); xlo->xlo_backing_file = file; xlo->old_gfp_mask = mapping_gfp_mask(file->f_mapping); mapping_set_gfp_mask(file->f_mapping, xlo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); xloop_update_dio(xlo); blk_mq_unfreeze_queue(xlo->xlo_queue); partscan = xlo->xlo_flags & XLO_FLAGS_PARTSCAN; xloop_global_unlock(xlo, is_xloop); /* * Flush xloop_validate_file() before fput(), for l->xlo_backing_file * might be pointing at old_file which might be the last reference. */ if (!is_xloop) { mutex_lock(&xloop_validate_mutex); mutex_unlock(&xloop_validate_mutex); } /* * We must drop file reference outside of xlo_mutex as dropping * the file ref can take open_mutex which creates circular locking * dependency. */ fput(old_file); if (partscan) xloop_reread_partitions(xlo); return 0; out_err: xloop_global_unlock(xlo, is_xloop); out_putf: fput(file); return error; } /* xloop sysfs attributes */ static ssize_t xloop_attr_show(struct device *dev, char *page, ssize_t (*callback)(struct xloop_device *, char *)) { struct gendisk *disk = dev_to_disk(dev); struct xloop_device *xlo = disk->private_data; return callback(xlo, page); } #define XLOOP_ATTR_RO(_name) \ static ssize_t xloop_attr_##_name##_show(struct xloop_device *, char *); \ static ssize_t xloop_attr_do_show_##_name(struct device *d, \ struct device_attribute *attr, char *b) \ { \ return xloop_attr_show(d, b, xloop_attr_##_name##_show); \ } \ static struct device_attribute xloop_attr_##_name = \ __ATTR(_name, 0444, xloop_attr_do_show_##_name, NULL); static ssize_t xloop_attr_backing_file_show(struct xloop_device *xlo, char *buf) { ssize_t ret; char *p = NULL; spin_lock_irq(&xlo->xlo_lock); if (xlo->xlo_backing_file) p = file_path(xlo->xlo_backing_file, buf, PAGE_SIZE - 1); spin_unlock_irq(&xlo->xlo_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 xloop_attr_file_fmt_type_show(struct xloop_device *xlo, char *buf) { ssize_t len = 0; len = xloop_file_fmt_print_type(xlo->xlo_fmt->file_fmt_type, buf); len += sprintf(buf + len, "\n"); return len; } static ssize_t xloop_attr_offset_show(struct xloop_device *xlo, char *buf) { return sprintf(buf, "%llu\n", (unsigned long long)xlo->xlo_offset); } static ssize_t xloop_attr_sizelimit_show(struct xloop_device *xlo, char *buf) { return sprintf(buf, "%llu\n", (unsigned long long)xlo->xlo_sizelimit); } static ssize_t xloop_attr_autoclear_show(struct xloop_device *xlo, char *buf) { int autoclear = (xlo->xlo_flags & XLO_FLAGS_AUTOCLEAR); return sprintf(buf, "%s\n", autoclear ? "1" : "0"); } static ssize_t xloop_attr_partscan_show(struct xloop_device *xlo, char *buf) { int partscan = (xlo->xlo_flags & XLO_FLAGS_PARTSCAN); return sprintf(buf, "%s\n", partscan ? "1" : "0"); } static ssize_t xloop_attr_dio_show(struct xloop_device *xlo, char *buf) { int dio = (xlo->xlo_flags & XLO_FLAGS_DIRECT_IO); return sprintf(buf, "%s\n", dio ? "1" : "0"); } XLOOP_ATTR_RO(backing_file); XLOOP_ATTR_RO(file_fmt_type); XLOOP_ATTR_RO(offset); XLOOP_ATTR_RO(sizelimit); XLOOP_ATTR_RO(autoclear); XLOOP_ATTR_RO(partscan); XLOOP_ATTR_RO(dio); static struct attribute *xloop_attrs[] = { &xloop_attr_backing_file.attr, &xloop_attr_file_fmt_type.attr, &xloop_attr_offset.attr, &xloop_attr_sizelimit.attr, &xloop_attr_autoclear.attr, &xloop_attr_partscan.attr, &xloop_attr_dio.attr, NULL, }; static struct attribute_group xloop_attribute_group = { .name = "xloop", .attrs = xloop_attrs, }; static void xloop_sysfs_init(struct xloop_device *xlo) { xlo->sysfs_inited = !sysfs_create_group(&disk_to_dev(xlo->xlo_disk)->kobj, &xloop_attribute_group); } static void xloop_sysfs_exit(struct xloop_device *xlo) { if (xlo->sysfs_inited) sysfs_remove_group(&disk_to_dev(xlo->xlo_disk)->kobj, &xloop_attribute_group); } static void xloop_config_discard(struct xloop_device *xlo) { struct file *file = xlo->xlo_backing_file; struct inode *inode = file->f_mapping->host; struct request_queue *q = xlo->xlo_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 xloop discards result in blkdev_issue_zeroout(), * not blkdev_issue_discard(). This maintains consistent behavior with * file-backed xloop devices: discarded regions read back as zero. */ if (S_ISBLK(inode->i_mode) && !xlo->xlo_encrypt_key_size) { struct request_queue *backingq = bdev_get_queue(I_BDEV(inode)); max_discard_sectors = backingq->limits.max_write_zeroes_sectors; granularity = backingq->limits.discard_granularity ?: queue_physical_block_size(backingq); /* * We use punch hole to reclaim the free space used by the * image a.k.a. discard. However we do not support discard if * encryption is enabled, because it may give an attacker * useful information. */ } else if (!file->f_op->fallocate || xlo->xlo_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); #if LINUX_VERSION_CODE < KERNEL_VERSION(5, 19, 0) blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); #endif } else { q->limits.discard_granularity = 0; blk_queue_max_discard_sectors(q, 0); blk_queue_max_write_zeroes_sectors(q, 0); #if LINUX_VERSION_CODE < KERNEL_VERSION(5, 19, 0) blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); #endif } q->limits.discard_alignment = 0; } struct xloop_worker { struct rb_node rb_node; struct work_struct work; struct list_head cmd_list; struct list_head idle_list; struct xloop_device *xlo; struct cgroup_subsys_state *blkcg_css; unsigned long last_ran_at; }; static void xloop_workfn(struct work_struct *work); static void xloop_rootcg_workfn(struct work_struct *work); static void xloop_free_idle_workers(struct timer_list *timer); #ifdef CONFIG_BLK_CGROUP static inline int queue_on_root_worker(struct cgroup_subsys_state *css) { return !css || css == blkcg_root_css; } #else static inline int queue_on_root_worker(struct cgroup_subsys_state *css) { return !css; } #endif static void xloop_queue_work(struct xloop_device *xlo, struct xloop_cmd *cmd) { struct rb_node **node = &(xlo->worker_tree.rb_node), *parent = NULL; struct xloop_worker *cur_worker, *worker = NULL; struct work_struct *work; struct list_head *cmd_list; spin_lock_irq(&xlo->xlo_work_lock); if (queue_on_root_worker(cmd->blkcg_css)) goto queue_work; node = &xlo->worker_tree.rb_node; while (*node) { parent = *node; cur_worker = container_of(*node, struct xloop_worker, rb_node); if (cur_worker->blkcg_css == cmd->blkcg_css) { worker = cur_worker; break; } else if ((long)cur_worker->blkcg_css < (long)cmd->blkcg_css) { node = &(*node)->rb_left; } else { node = &(*node)->rb_right; } } if (worker) goto queue_work; worker = kzalloc(sizeof(struct xloop_worker), GFP_NOWAIT | __GFP_NOWARN); /* * In the event we cannot allocate a worker, just queue on the * rootcg worker and issue the I/O as the rootcg */ if (!worker) { cmd->blkcg_css = NULL; if (cmd->memcg_css) css_put(cmd->memcg_css); cmd->memcg_css = NULL; goto queue_work; } worker->blkcg_css = cmd->blkcg_css; css_get(worker->blkcg_css); INIT_WORK(&worker->work, xloop_workfn); INIT_LIST_HEAD(&worker->cmd_list); INIT_LIST_HEAD(&worker->idle_list); worker->xlo = xlo; rb_link_node(&worker->rb_node, parent, node); rb_insert_color(&worker->rb_node, &xlo->worker_tree); queue_work: if (worker) { /* * We need to remove from the idle list here while * holding the lock so that the idle timer doesn't * free the worker */ if (!list_empty(&worker->idle_list)) list_del_init(&worker->idle_list); work = &worker->work; cmd_list = &worker->cmd_list; } else { work = &xlo->rootcg_work; cmd_list = &xlo->rootcg_cmd_list; } list_add_tail(&cmd->list_entry, cmd_list); queue_work(xlo->workqueue, work); spin_unlock_irq(&xlo->xlo_work_lock); } static void xloop_update_rotational(struct xloop_device *xlo) { struct file *file = xlo->xlo_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 = xlo->xlo_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 xloop_release_xfer(struct xloop_device *xlo) { int err = 0; struct xloop_func_table *xfer = xlo->xlo_encryption; if (xfer) { if (xfer->release) err = xfer->release(xlo); xlo->transfer = NULL; xlo->xlo_encryption = NULL; module_put(xfer->owner); } return err; } static int xloop_init_xfer(struct xloop_device *xlo, struct xloop_func_table *xfer, const struct xloop_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(xlo, i); if (err) module_put(owner); else xlo->xlo_encryption = xfer; } return err; } /** * xloop_set_status_from_info - configure device from xloop_info * @xlo: struct xloop_device to configure * @info: struct xloop_info64 to configure the device with * * Configures the xloop device parameters according to the passed * in xloop_info64 configuration. */ static int xloop_set_status_from_info(struct xloop_device *xlo, const struct xloop_info64 *info) { int err; struct xloop_func_table *xfer; kuid_t uid = current_uid(); if ((unsigned int) info->xlo_encrypt_key_size > XLO_KEY_SIZE) return -EINVAL; err = xloop_release_xfer(xlo); if (err) return err; if (info->xlo_encrypt_type) { unsigned int type = info->xlo_encrypt_type; if (type >= MAX_XLO_CRYPT) return -EINVAL; xfer = xfer_funcs[type]; if (xfer == NULL) return -EINVAL; } else xfer = NULL; err = xloop_init_xfer(xlo, xfer, info); if (err) return err; xlo->xlo_offset = info->xlo_offset; xlo->xlo_sizelimit = info->xlo_sizelimit; memcpy(xlo->xlo_file_name, info->xlo_file_name, XLO_NAME_SIZE); memcpy(xlo->xlo_crypt_name, info->xlo_crypt_name, XLO_NAME_SIZE); xlo->xlo_file_name[XLO_NAME_SIZE-1] = 0; xlo->xlo_crypt_name[XLO_NAME_SIZE-1] = 0; if (!xfer) xfer = &none_funcs; xlo->transfer = xfer->transfer; xlo->ioctl = xfer->ioctl; xlo->xlo_flags = info->xlo_flags; xlo->xlo_encrypt_key_size = info->xlo_encrypt_key_size; xlo->xlo_init[0] = info->xlo_init[0]; xlo->xlo_init[1] = info->xlo_init[1]; if (info->xlo_encrypt_key_size) { memcpy(xlo->xlo_encrypt_key, info->xlo_encrypt_key, info->xlo_encrypt_key_size); xlo->xlo_key_owner = uid; } return 0; } static int xloop_configure(struct xloop_device *xlo, fmode_t mode, struct block_device *bdev, const struct xloop_config *config) { struct file *file = fget(config->fd); struct inode *inode; struct address_space *mapping; int error; loff_t size; bool partscan; unsigned short bsize; bool is_xloop; if (!file) return -EBADF; is_xloop = is_xloop_device(file); /* This is safe, since we have a reference from open(). */ __module_get(THIS_MODULE); /* * If we don't hold exclusive handle for the device, upgrade to it * here to avoid changing device under exclusive owner. */ if (!(mode & FMODE_EXCL)) { error = bd_prepare_to_claim(bdev, xloop_configure); if (error) goto out_putf; } error = xloop_global_lock_killable(xlo, is_xloop); if (error) goto out_bdev; error = -EBUSY; if (xlo->xlo_state != Xlo_unbound) goto out_unlock; error = xloop_validate_file(file, bdev); if (error) goto out_unlock; mapping = file->f_mapping; inode = mapping->host; if ((config->info.xlo_flags & ~XLOOP_CONFIGURE_SETTABLE_FLAGS) != 0) { error = -EINVAL; goto out_unlock; } if (config->block_size) { error = blk_validate_block_size(config->block_size); if (error) goto out_unlock; } error = xloop_set_status_from_info(xlo, &config->info); if (error) goto out_unlock; if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || !file->f_op->write_iter) xlo->xlo_flags |= XLO_FLAGS_READ_ONLY; xlo->workqueue = alloc_workqueue("xloop%d", WQ_UNBOUND | WQ_FREEZABLE, 0, xlo->xlo_number); if (!xlo->workqueue) { error = -ENOMEM; goto out_unlock; } disk_force_media_change(xlo->xlo_disk, DISK_EVENT_MEDIA_CHANGE); set_disk_ro(xlo->xlo_disk, (xlo->xlo_flags & XLO_FLAGS_READ_ONLY) != 0); INIT_WORK(&xlo->rootcg_work, xloop_rootcg_workfn); INIT_LIST_HEAD(&xlo->rootcg_cmd_list); INIT_LIST_HEAD(&xlo->idle_worker_list); xlo->worker_tree = RB_ROOT; timer_setup(&xlo->timer, xloop_free_idle_workers, TIMER_DEFERRABLE); xlo->use_dio = xlo->xlo_flags & XLO_FLAGS_DIRECT_IO; xlo->xlo_device = bdev; xlo->xlo_backing_file = file; xlo->old_gfp_mask = mapping_gfp_mask(mapping); mapping_set_gfp_mask(mapping, xlo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); error = xloop_file_fmt_init(xlo->xlo_fmt, config->info.xlo_file_fmt_type); if (error) goto out_unlock; if (!(xlo->xlo_flags & XLO_FLAGS_READ_ONLY) && file->f_op->fsync) blk_queue_write_cache(xlo->xlo_queue, true, false); if (config->block_size) bsize = config->block_size; else if ((xlo->xlo_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(xlo->xlo_queue, bsize); blk_queue_physical_block_size(xlo->xlo_queue, bsize); blk_queue_io_min(xlo->xlo_queue, bsize); xloop_config_discard(xlo); xloop_update_rotational(xlo); xloop_update_dio(xlo); xloop_sysfs_init(xlo); size = get_xloop_size(xlo, file); xloop_set_size(xlo, size); /* Order wrt reading xlo_state in xloop_validate_file(). */ wmb(); xlo->xlo_state = Xlo_bound; if (part_shift) xlo->xlo_flags |= XLO_FLAGS_PARTSCAN; partscan = xlo->xlo_flags & XLO_FLAGS_PARTSCAN; if (partscan) xlo->xlo_disk->flags &= ~GENHD_FL_NO_PART; xloop_global_unlock(xlo, is_xloop); if (partscan) xloop_reread_partitions(xlo); if (!(mode & FMODE_EXCL)) bd_abort_claiming(bdev, xloop_configure); return 0; out_unlock: xloop_global_unlock(xlo, is_xloop); out_bdev: if (!(mode & FMODE_EXCL)) bd_abort_claiming(bdev, xloop_configure); out_putf: fput(file); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); return error; } static int __xloop_clr_fd(struct xloop_device *xlo, bool release) { struct file *filp = NULL; gfp_t gfp = xlo->old_gfp_mask; struct block_device *bdev = xlo->xlo_device; int err = 0; bool partscan = false; int xlo_number; struct xloop_worker *pos, *worker; /* * Flush xloop_configure() and xloop_change_fd(). It is acceptable for * xloop_validate_file() to succeed, for actual clear operation has not * started yet. */ mutex_lock(&xloop_validate_mutex); mutex_unlock(&xloop_validate_mutex); /* * xloop_validate_file() now fails because l->xlo_state != Xlo_bound * became visible. */ mutex_lock(&xlo->xlo_mutex); if (WARN_ON_ONCE(xlo->xlo_state != Xlo_rundown)) { err = -ENXIO; goto out_unlock; } filp = xlo->xlo_backing_file; if (filp == NULL) { err = -EINVAL; goto out_unlock; } if (test_bit(QUEUE_FLAG_WC, &xlo->xlo_queue->queue_flags)) blk_queue_write_cache(xlo->xlo_queue, false, false); /* freeze request queue during the transition */ blk_mq_freeze_queue(xlo->xlo_queue); xloop_file_fmt_exit(xlo->xlo_fmt); destroy_workqueue(xlo->workqueue); spin_lock_irq(&xlo->xlo_work_lock); list_for_each_entry_safe(worker, pos, &xlo->idle_worker_list, idle_list) { list_del(&worker->idle_list); rb_erase(&worker->rb_node, &xlo->worker_tree); css_put(worker->blkcg_css); kfree(worker); } spin_unlock_irq(&xlo->xlo_work_lock); del_timer_sync(&xlo->timer); spin_lock_irq(&xlo->xlo_lock); xlo->xlo_backing_file = NULL; spin_unlock_irq(&xlo->xlo_lock); xloop_release_xfer(xlo); xlo->transfer = NULL; xlo->ioctl = NULL; xlo->xlo_device = NULL; xlo->xlo_encryption = NULL; xlo->xlo_offset = 0; xlo->xlo_sizelimit = 0; xlo->xlo_encrypt_key_size = 0; memset(xlo->xlo_encrypt_key, 0, XLO_KEY_SIZE); memset(xlo->xlo_crypt_name, 0, XLO_NAME_SIZE); memset(xlo->xlo_file_name, 0, XLO_NAME_SIZE); blk_queue_logical_block_size(xlo->xlo_queue, 512); blk_queue_physical_block_size(xlo->xlo_queue, 512); blk_queue_io_min(xlo->xlo_queue, 512); if (bdev) { invalidate_bdev(bdev); bdev->bd_inode->i_mapping->wb_err = 0; } set_capacity(xlo->xlo_disk, 0); xloop_sysfs_exit(xlo); if (bdev) { /* 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(xlo->xlo_queue); partscan = xlo->xlo_flags & XLO_FLAGS_PARTSCAN && bdev; xlo_number = xlo->xlo_number; disk_force_media_change(xlo->xlo_disk, DISK_EVENT_MEDIA_CHANGE); out_unlock: mutex_unlock(&xlo->xlo_mutex); if (partscan) { /* * open_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, xlo_refcnt * must be at least one and it can only become zero when the * current holder is released. */ if (!release) mutex_lock(&xlo->xlo_disk->open_mutex); err = bdev_disk_changed(xlo->xlo_disk, false); if (!release) mutex_unlock(&xlo->xlo_disk->open_mutex); if (err) dev_warn(xloop_device_to_dev(xlo), "partition scan of xloop%d failed (rc=%d)\n", xlo_number, err); /* Device is gone, no point in returning error */ err = 0; } /* * xlo->xlo_state is set to Xlo_unbound here after above partscan has * finished. * * There cannot be anybody else entering __xloop_clr_fd() as * xlo->xlo_backing_file is already cleared and Xlo_rundown state * protects us from all the other places trying to change the 'xlo' * device. */ mutex_lock(&xlo->xlo_mutex); xlo->xlo_flags = 0; if (!part_shift) xlo->xlo_disk->flags |= GENHD_FL_NO_PART; xlo->xlo_state = Xlo_unbound; mutex_unlock(&xlo->xlo_mutex); /* * Need not hold xlo_mutex to fput backing file. Calling fput holding * xlo_mutex triggers a circular lock dependency possibility warning as * fput can take open_mutex which is usually taken before xlo_mutex. */ if (filp) fput(filp); return err; } static int xloop_clr_fd(struct xloop_device *xlo) { int err; err = mutex_lock_killable(&xlo->xlo_mutex); if (err) return err; if (xlo->xlo_state != Xlo_bound) { mutex_unlock(&xlo->xlo_mutex); return -ENXIO; } /* * If we've explicitly asked to tear down the xloop 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 xloopback device whenever they appear. xfstests is notorious for * failing tests because blkid via udev races with a xlosetup * /do something like mkfs/xlosetup -d causing the xlosetup -d * command to fail with EBUSY. */ if (atomic_read(&xlo->xlo_refcnt) > 1) { xlo->xlo_flags |= XLO_FLAGS_AUTOCLEAR; mutex_unlock(&xlo->xlo_mutex); return 0; } xlo->xlo_state = Xlo_rundown; mutex_unlock(&xlo->xlo_mutex); return __xloop_clr_fd(xlo, false); } static int xloop_set_status(struct xloop_device *xlo, const struct xloop_info64 *info) { int err; kuid_t uid = current_uid(); int prev_xlo_flags; bool partscan = false; bool size_changed = false; err = mutex_lock_killable(&xlo->xlo_mutex); if (err) return err; if (xlo->xlo_encrypt_key_size && !uid_eq(xlo->xlo_key_owner, uid) && !capable(CAP_SYS_ADMIN)) { err = -EPERM; goto out_unlock; } if (xlo->xlo_state != Xlo_bound) { err = -ENXIO; goto out_unlock; } if (xlo->xlo_offset != info->xlo_offset || xlo->xlo_sizelimit != info->xlo_sizelimit) { size_changed = true; sync_blockdev(xlo->xlo_device); invalidate_bdev(xlo->xlo_device); } /* I/O need to be drained during transfer transition */ blk_mq_freeze_queue(xlo->xlo_queue); if (size_changed && xlo->xlo_device->bd_inode->i_mapping->nrpages) { /* If any pages were dirtied after invalidate_bdev(), try again */ err = -EAGAIN; dev_warn(xloop_device_to_dev(xlo), "xloop%d (%s) has still dirty pages (nrpages=%lu)\n", xlo->xlo_number, xlo->xlo_file_name, xlo->xlo_device->bd_inode->i_mapping->nrpages); goto out_unfreeze; } prev_xlo_flags = xlo->xlo_flags; err = xloop_set_status_from_info(xlo, info); if (err) goto out_unfreeze; /* Mask out flags that can't be set using XLOOP_SET_STATUS. */ xlo->xlo_flags &= XLOOP_SET_STATUS_SETTABLE_FLAGS; /* For those flags, use the previous values instead */ xlo->xlo_flags |= prev_xlo_flags & ~XLOOP_SET_STATUS_SETTABLE_FLAGS; /* For flags that can't be cleared, use previous values too */ xlo->xlo_flags |= prev_xlo_flags & ~XLOOP_SET_STATUS_CLEARABLE_FLAGS; if (xlo->xlo_fmt->file_fmt_type != info->xlo_file_fmt_type) { /* xloop file format has changed, so change file format driver */ err = xloop_file_fmt_change(xlo->xlo_fmt, info->xlo_file_fmt_type); if (err) goto out_unfreeze; /* After change of the file format, recalculate the capacity of the xloop device. */ size_changed = true; } if (size_changed) { loff_t new_size = get_xloop_size(xlo, xlo->xlo_backing_file); xloop_set_size(xlo, new_size); } xloop_config_discard(xlo); /* update dio if xlo_offset or transfer is changed */ __xloop_update_dio(xlo, xlo->use_dio); out_unfreeze: blk_mq_unfreeze_queue(xlo->xlo_queue); if (!err && (xlo->xlo_flags & XLO_FLAGS_PARTSCAN) && !(prev_xlo_flags & XLO_FLAGS_PARTSCAN)) { xlo->xlo_disk->flags &= ~GENHD_FL_NO_PART; partscan = true; } out_unlock: mutex_unlock(&xlo->xlo_mutex); if (partscan) xloop_reread_partitions(xlo); return err; } static int xloop_get_status(struct xloop_device *xlo, struct xloop_info64 *info) { struct path path; struct kstat stat; int ret; ret = mutex_lock_killable(&xlo->xlo_mutex); if (ret) return ret; if (xlo->xlo_state != Xlo_bound) { mutex_unlock(&xlo->xlo_mutex); return -ENXIO; } memset(info, 0, sizeof(*info)); info->xlo_number = xlo->xlo_number; info->xlo_offset = xlo->xlo_offset; info->xlo_sizelimit = xlo->xlo_sizelimit; info->xlo_flags = xlo->xlo_flags; memcpy(info->xlo_file_name, xlo->xlo_file_name, XLO_NAME_SIZE); memcpy(info->xlo_crypt_name, xlo->xlo_crypt_name, XLO_NAME_SIZE); info->xlo_encrypt_type = xlo->xlo_encryption ? xlo->xlo_encryption->number : 0; if (xlo->xlo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { info->xlo_encrypt_key_size = xlo->xlo_encrypt_key_size; memcpy(info->xlo_encrypt_key, xlo->xlo_encrypt_key, xlo->xlo_encrypt_key_size); } /* Drop xlo_mutex while we call into the filesystem. */ path = xlo->xlo_backing_file->f_path; path_get(&path); mutex_unlock(&xlo->xlo_mutex); ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT); if (!ret) { info->xlo_device = huge_encode_dev(stat.dev); info->xlo_inode = stat.ino; info->xlo_rdevice = huge_encode_dev(stat.rdev); } path_put(&path); return ret; } static void xloop_info64_from_old(const struct xloop_info *info, struct xloop_info64 *info64) { memset(info64, 0, sizeof(*info64)); info64->xlo_number = info->xlo_number; info64->xlo_device = info->xlo_device; info64->xlo_inode = info->xlo_inode; info64->xlo_rdevice = info->xlo_rdevice; info64->xlo_offset = info->xlo_offset; info64->xlo_sizelimit = 0; info64->xlo_encrypt_type = info->xlo_encrypt_type; info64->xlo_encrypt_key_size = info->xlo_encrypt_key_size; info64->xlo_flags = info->xlo_flags; info64->xlo_init[0] = info->xlo_init[0]; info64->xlo_init[1] = info->xlo_init[1]; if (info->xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) memcpy(info64->xlo_crypt_name, info->xlo_name, XLO_NAME_SIZE); else memcpy(info64->xlo_file_name, info->xlo_name, XLO_NAME_SIZE); memcpy(info64->xlo_encrypt_key, info->xlo_encrypt_key, XLO_KEY_SIZE); } static int xloop_info64_to_old(const struct xloop_info64 *info64, struct xloop_info *info) { memset(info, 0, sizeof(*info)); info->xlo_number = info64->xlo_number; info->xlo_device = info64->xlo_device; info->xlo_inode = info64->xlo_inode; info->xlo_rdevice = info64->xlo_rdevice; info->xlo_offset = info64->xlo_offset; info->xlo_encrypt_type = info64->xlo_encrypt_type; info->xlo_encrypt_key_size = info64->xlo_encrypt_key_size; info->xlo_flags = info64->xlo_flags; info->xlo_init[0] = info64->xlo_init[0]; info->xlo_init[1] = info64->xlo_init[1]; if (info->xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) memcpy(info->xlo_name, info64->xlo_crypt_name, XLO_NAME_SIZE); else memcpy(info->xlo_name, info64->xlo_file_name, XLO_NAME_SIZE); memcpy(info->xlo_encrypt_key, info64->xlo_encrypt_key, XLO_KEY_SIZE); /* error in case values were truncated */ if (info->xlo_device != info64->xlo_device || info->xlo_rdevice != info64->xlo_rdevice || info->xlo_inode != info64->xlo_inode || info->xlo_offset != info64->xlo_offset) return -EOVERFLOW; return 0; } static int xloop_set_status_old(struct xloop_device *xlo, const struct xloop_info __user *arg) { struct xloop_info info; struct xloop_info64 info64; if (copy_from_user(&info, arg, sizeof(struct xloop_info))) return -EFAULT; xloop_info64_from_old(&info, &info64); return xloop_set_status(xlo, &info64); } static int xloop_set_status64(struct xloop_device *xlo, const struct xloop_info64 __user *arg) { struct xloop_info64 info64; if (copy_from_user(&info64, arg, sizeof(struct xloop_info64))) return -EFAULT; return xloop_set_status(xlo, &info64); } static int xloop_get_status_old(struct xloop_device *xlo, struct xloop_info __user *arg) { struct xloop_info info; struct xloop_info64 info64; int err; if (!arg) return -EINVAL; err = xloop_get_status(xlo, &info64); if (!err) err = xloop_info64_to_old(&info64, &info); if (!err && copy_to_user(arg, &info, sizeof(info))) err = -EFAULT; return err; } static int xloop_get_status64(struct xloop_device *xlo, struct xloop_info64 __user *arg) { struct xloop_info64 info64; int err; if (!arg) return -EINVAL; err = xloop_get_status(xlo, &info64); if (!err && copy_to_user(arg, &info64, sizeof(info64))) err = -EFAULT; return err; } static int xloop_set_capacity(struct xloop_device *xlo) { loff_t size; if (unlikely(xlo->xlo_state != Xlo_bound)) return -ENXIO; size = get_xloop_size(xlo, xlo->xlo_backing_file); xloop_set_size(xlo, size); return 0; } static int xloop_set_dio(struct xloop_device *xlo, unsigned long arg) { int error = -ENXIO; if (xlo->xlo_state != Xlo_bound) goto out; __xloop_update_dio(xlo, !!arg); if (xlo->use_dio == !!arg) return 0; error = -EINVAL; out: return error; } static int xloop_set_block_size(struct xloop_device *xlo, unsigned long arg) { int err = 0; if (xlo->xlo_state != Xlo_bound) return -ENXIO; err = blk_validate_block_size(arg); if (err) return err; if (xlo->xlo_queue->limits.logical_block_size == arg) return 0; sync_blockdev(xlo->xlo_device); invalidate_bdev(xlo->xlo_device); blk_mq_freeze_queue(xlo->xlo_queue); /* invalidate_bdev should have truncated all the pages */ if (xlo->xlo_device->bd_inode->i_mapping->nrpages) { err = -EAGAIN; dev_warn(xloop_device_to_dev(xlo), "xloop%d (%s) has still dirty pages (nrpages=%lu)\n", xlo->xlo_number, xlo->xlo_file_name, xlo->xlo_device->bd_inode->i_mapping->nrpages); goto out_unfreeze; } blk_queue_logical_block_size(xlo->xlo_queue, arg); blk_queue_physical_block_size(xlo->xlo_queue, arg); blk_queue_io_min(xlo->xlo_queue, arg); xloop_update_dio(xlo); out_unfreeze: blk_mq_unfreeze_queue(xlo->xlo_queue); return err; } static int xlo_simple_ioctl(struct xloop_device *xlo, unsigned int cmd, unsigned long arg) { int err; err = mutex_lock_killable(&xlo->xlo_mutex); if (err) return err; switch (cmd) { case XLOOP_SET_CAPACITY: err = xloop_set_capacity(xlo); break; case XLOOP_SET_DIRECT_IO: err = xloop_set_dio(xlo, arg); break; case XLOOP_SET_BLOCK_SIZE: err = xloop_set_block_size(xlo, arg); break; default: err = xlo->ioctl ? xlo->ioctl(xlo, cmd, arg) : -EINVAL; } mutex_unlock(&xlo->xlo_mutex); return err; } static int xlo_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { struct xloop_device *xlo = bdev->bd_disk->private_data; void __user *argp = (void __user *) arg; int err; switch (cmd) { case XLOOP_SET_FD: { /* * Legacy case - pass in a zeroed out struct xloop_config with * only the file descriptor set , which corresponds with the * default parameters we'd have used otherwise. */ struct xloop_config config; memset(&config, 0, sizeof(config)); config.fd = arg; return xloop_configure(xlo, mode, bdev, &config); } case XLOOP_CONFIGURE: { struct xloop_config config; if (copy_from_user(&config, argp, sizeof(config))) return -EFAULT; return xloop_configure(xlo, mode, bdev, &config); } case XLOOP_CHANGE_FD: return xloop_change_fd(xlo, bdev, arg); case XLOOP_CLR_FD: return xloop_clr_fd(xlo); case XLOOP_SET_STATUS: err = -EPERM; if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) err = xloop_set_status_old(xlo, argp); break; case XLOOP_GET_STATUS: return xloop_get_status_old(xlo, argp); case XLOOP_SET_STATUS64: err = -EPERM; if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) err = xloop_set_status64(xlo, argp); break; case XLOOP_GET_STATUS64: return xloop_get_status64(xlo, argp); case XLOOP_SET_CAPACITY: case XLOOP_SET_DIRECT_IO: case XLOOP_SET_BLOCK_SIZE: if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN)) return -EPERM; fallthrough; default: err = xlo_simple_ioctl(xlo, cmd, arg); break; } return err; } #ifdef CONFIG_COMPAT struct compat_xloop_info { compat_int_t xlo_number; /* ioctl r/o */ compat_dev_t xlo_device; /* ioctl r/o */ compat_ulong_t xlo_inode; /* ioctl r/o */ compat_dev_t xlo_rdevice; /* ioctl r/o */ compat_int_t xlo_offset; compat_int_t xlo_encrypt_type; compat_int_t xlo_encrypt_key_size; /* ioctl w/o */ compat_int_t xlo_flags; /* ioctl r/o */ char xlo_name[XLO_NAME_SIZE]; unsigned char xlo_encrypt_key[XLO_KEY_SIZE]; /* ioctl w/o */ compat_ulong_t xlo_init[2]; char reserved[4]; }; /* * Transfer 32-bit compatibility structure in userspace to 64-bit xloop info * - noinlined to reduce stack space usage in main part of driver */ static noinline int xloop_info64_from_compat(const struct compat_xloop_info __user *arg, struct xloop_info64 *info64) { struct compat_xloop_info info; if (copy_from_user(&info, arg, sizeof(info))) return -EFAULT; memset(info64, 0, sizeof(*info64)); info64->xlo_number = info.xlo_number; info64->xlo_device = info.xlo_device; info64->xlo_inode = info.xlo_inode; info64->xlo_rdevice = info.xlo_rdevice; info64->xlo_offset = info.xlo_offset; info64->xlo_sizelimit = 0; info64->xlo_encrypt_type = info.xlo_encrypt_type; info64->xlo_encrypt_key_size = info.xlo_encrypt_key_size; info64->xlo_flags = info.xlo_flags; info64->xlo_init[0] = info.xlo_init[0]; info64->xlo_init[1] = info.xlo_init[1]; if (info.xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) memcpy(info64->xlo_crypt_name, info.xlo_name, XLO_NAME_SIZE); else memcpy(info64->xlo_file_name, info.xlo_name, XLO_NAME_SIZE); memcpy(info64->xlo_encrypt_key, info.xlo_encrypt_key, XLO_KEY_SIZE); return 0; } /* * Transfer 64-bit xloop info to 32-bit compatibility structure in userspace * - noinlined to reduce stack space usage in main part of driver */ static noinline int xloop_info64_to_compat(const struct xloop_info64 *info64, struct compat_xloop_info __user *arg) { struct compat_xloop_info info; memset(&info, 0, sizeof(info)); info.xlo_number = info64->xlo_number; info.xlo_device = info64->xlo_device; info.xlo_inode = info64->xlo_inode; info.xlo_rdevice = info64->xlo_rdevice; info.xlo_offset = info64->xlo_offset; info.xlo_encrypt_type = info64->xlo_encrypt_type; info.xlo_encrypt_key_size = info64->xlo_encrypt_key_size; info.xlo_flags = info64->xlo_flags; info.xlo_init[0] = info64->xlo_init[0]; info.xlo_init[1] = info64->xlo_init[1]; if (info.xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) memcpy(info.xlo_name, info64->xlo_crypt_name, XLO_NAME_SIZE); else memcpy(info.xlo_name, info64->xlo_file_name, XLO_NAME_SIZE); memcpy(info.xlo_encrypt_key, info64->xlo_encrypt_key, XLO_KEY_SIZE); /* error in case values were truncated */ if (info.xlo_device != info64->xlo_device || info.xlo_rdevice != info64->xlo_rdevice || info.xlo_inode != info64->xlo_inode || info.xlo_offset != info64->xlo_offset || info.xlo_init[0] != info64->xlo_init[0] || info.xlo_init[1] != info64->xlo_init[1]) return -EOVERFLOW; if (copy_to_user(arg, &info, sizeof(info))) return -EFAULT; return 0; } static int xloop_set_status_compat(struct xloop_device *xlo, const struct compat_xloop_info __user *arg) { struct xloop_info64 info64; int ret; ret = xloop_info64_from_compat(arg, &info64); if (ret < 0) return ret; return xloop_set_status(xlo, &info64); } static int xloop_get_status_compat(struct xloop_device *xlo, struct compat_xloop_info __user *arg) { struct xloop_info64 info64; int err; if (!arg) return -EINVAL; err = xloop_get_status(xlo, &info64); if (!err) err = xloop_info64_to_compat(&info64, arg); return err; } static int xlo_compat_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { struct xloop_device *xlo = bdev->bd_disk->private_data; int err; switch (cmd) { case XLOOP_SET_STATUS: err = xloop_set_status_compat(xlo, (const struct compat_xloop_info __user *)arg); break; case XLOOP_GET_STATUS: err = xloop_get_status_compat(xlo, (struct compat_xloop_info __user *)arg); break; case XLOOP_SET_CAPACITY: case XLOOP_CLR_FD: case XLOOP_GET_STATUS64: case XLOOP_SET_STATUS64: case XLOOP_CONFIGURE: arg = (unsigned long) compat_ptr(arg); fallthrough; case XLOOP_SET_FD: case XLOOP_CHANGE_FD: case XLOOP_SET_BLOCK_SIZE: case XLOOP_SET_DIRECT_IO: err = xlo_ioctl(bdev, mode, cmd, arg); break; default: err = -ENOIOCTLCMD; break; } return err; } #endif static int xlo_open(struct block_device *bdev, fmode_t mode) { struct xloop_device *xlo = bdev->bd_disk->private_data; int err; err = mutex_lock_killable(&xlo->xlo_mutex); if (err) return err; if (xlo->xlo_state == Xlo_deleting) err = -ENXIO; else atomic_inc(&xlo->xlo_refcnt); mutex_unlock(&xlo->xlo_mutex); return err; } static void xlo_release(struct gendisk *disk, fmode_t mode) { struct xloop_device *xlo = disk->private_data; mutex_lock(&xlo->xlo_mutex); if (atomic_dec_return(&xlo->xlo_refcnt)) goto out_unlock; if (xlo->xlo_flags & XLO_FLAGS_AUTOCLEAR) { if (xlo->xlo_state != Xlo_bound) goto out_unlock; xlo->xlo_state = Xlo_rundown; mutex_unlock(&xlo->xlo_mutex); /* * In autoclear mode, stop the xloop thread * and remove configuration after last close. */ __xloop_clr_fd(xlo, true); return; } else if (xlo->xlo_state == Xlo_bound) { /* * Otherwise keep thread (if running) and config, * but flush possible ongoing bios in thread. */ blk_mq_freeze_queue(xlo->xlo_queue); blk_mq_unfreeze_queue(xlo->xlo_queue); } out_unlock: mutex_unlock(&xlo->xlo_mutex); } static const struct block_device_operations xlo_fops = { .owner = THIS_MODULE, .open = xlo_open, .release = xlo_release, .ioctl = xlo_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = xlo_compat_ioctl, #endif }; /* * And now the modules code and kernel interface. */ static int max_xloop; module_param(max_xloop, int, 0444); MODULE_PARM_DESC(max_xloop, "Maximum number of xloop devices"); module_param(max_part, int, 0444); MODULE_PARM_DESC(max_part, "Maximum number of partitions per xloop device"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Manuel Bentele "); MODULE_VERSION(XLOOP_VERSION); MODULE_ALIAS_BLOCKDEV_MAJOR(XLOOP_MAJOR); int xloop_register_transfer(struct xloop_func_table *funcs) { unsigned int n = funcs->number; if (n >= MAX_XLO_CRYPT || xfer_funcs[n]) return -EINVAL; xfer_funcs[n] = funcs; return 0; } EXPORT_SYMBOL(xloop_register_transfer); int xloop_unregister_transfer(int number) { unsigned int n = number; struct xloop_func_table *xfer = xfer_funcs[n]; if (n == 0 || n >= MAX_XLO_CRYPT || xfer == NULL) return -EINVAL; /* * This function is called from only cleanup_cryptoxloop(). * Given that each xloop device that has a transfer enabled holds a * reference to the module implementing it we should never get here * with a transfer that is set (unless forced module unloading is * requested). Thus, check module's refcount and warn if this is * not a clean unloading. */ #ifdef CONFIG_MODULE_UNLOAD if (xfer->owner && module_refcount(xfer->owner) != -1) pr_err("Danger! Unregistering an in use transfer function.\n"); #endif xfer_funcs[n] = NULL; return 0; } EXPORT_SYMBOL(xloop_unregister_transfer); static blk_status_t xloop_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct request *rq = bd->rq; struct xloop_cmd *cmd = blk_mq_rq_to_pdu(rq); struct xloop_device *xlo = rq->q->queuedata; blk_mq_start_request(rq); if (xlo->xlo_state != Xlo_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 = xlo->use_dio; break; } /* always use the first bio's css */ cmd->blkcg_css = NULL; cmd->memcg_css = NULL; #ifdef CONFIG_BLK_CGROUP if (rq->bio && rq->bio->bi_blkg) { #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 19, 0) cmd->blkcg_css = bio_blkcg_css(rq->bio); #else cmd->blkcg_css = &bio_blkcg(rq->bio)->css; #endif #ifdef CONFIG_MEMCG cmd->memcg_css = cgroup_get_e_css(cmd->blkcg_css->cgroup, &memory_cgrp_subsys); #endif } #endif xloop_queue_work(xlo, cmd); return BLK_STS_OK; } static void xloop_handle_cmd(struct xloop_cmd *cmd) { struct request *rq = blk_mq_rq_from_pdu(cmd); const bool write = op_is_write(req_op(rq)); struct xloop_device *xlo = rq->q->queuedata; int ret = 0; struct mem_cgroup *old_memcg = NULL; if (write && (xlo->xlo_flags & XLO_FLAGS_READ_ONLY)) { ret = -EIO; goto failed; } if (cmd->blkcg_css) kthread_associate_blkcg(cmd->blkcg_css); if (cmd->memcg_css) old_memcg = set_active_memcg( mem_cgroup_from_css(cmd->memcg_css)); ret = do_req_filebacked(xlo, rq); if (cmd->blkcg_css) kthread_associate_blkcg(NULL); if (cmd->memcg_css) { set_active_memcg(old_memcg); css_put(cmd->memcg_css); } failed: /* complete non-aio request */ if (!cmd->use_aio || ret) { if (ret == -EOPNOTSUPP) cmd->ret = ret; else cmd->ret = ret ? -EIO : 0; if (likely(!blk_should_fake_timeout(rq->q))) blk_mq_complete_request(rq); } } static void xloop_set_timer(struct xloop_device *xlo) { timer_reduce(&xlo->timer, jiffies + XLOOP_IDLE_WORKER_TIMEOUT); } static void xloop_process_work(struct xloop_worker *worker, struct list_head *cmd_list, struct xloop_device *xlo) { int orig_flags = current->flags; struct xloop_cmd *cmd; current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; spin_lock_irq(&xlo->xlo_work_lock); while (!list_empty(cmd_list)) { cmd = container_of( cmd_list->next, struct xloop_cmd, list_entry); list_del(cmd_list->next); spin_unlock_irq(&xlo->xlo_work_lock); xloop_handle_cmd(cmd); cond_resched(); spin_lock_irq(&xlo->xlo_work_lock); } /* * We only add to the idle list if there are no pending cmds * *and* the worker will not run again which ensures that it * is safe to free any worker on the idle list */ if (worker && !work_pending(&worker->work)) { worker->last_ran_at = jiffies; list_add_tail(&worker->idle_list, &xlo->idle_worker_list); xloop_set_timer(xlo); } spin_unlock_irq(&xlo->xlo_work_lock); current->flags = orig_flags; } static void xloop_workfn(struct work_struct *work) { struct xloop_worker *worker = container_of(work, struct xloop_worker, work); xloop_process_work(worker, &worker->cmd_list, worker->xlo); } static void xloop_rootcg_workfn(struct work_struct *work) { struct xloop_device *xlo = container_of(work, struct xloop_device, rootcg_work); xloop_process_work(NULL, &xlo->rootcg_cmd_list, xlo); } static void xloop_free_idle_workers(struct timer_list *timer) { struct xloop_device *xlo = container_of(timer, struct xloop_device, timer); struct xloop_worker *pos, *worker; spin_lock_irq(&xlo->xlo_work_lock); list_for_each_entry_safe(worker, pos, &xlo->idle_worker_list, idle_list) { if (time_is_after_jiffies(worker->last_ran_at + XLOOP_IDLE_WORKER_TIMEOUT)) break; list_del(&worker->idle_list); rb_erase(&worker->rb_node, &xlo->worker_tree); css_put(worker->blkcg_css); kfree(worker); } if (!list_empty(&xlo->idle_worker_list)) xloop_set_timer(xlo); spin_unlock_irq(&xlo->xlo_work_lock); } static const struct blk_mq_ops xloop_mq_ops = { .queue_rq = xloop_queue_rq, .complete = xlo_complete_rq, }; #ifdef CONFIG_DEBUG_FS static struct dentry *xloop_dbgfs_dir; #endif static int xloop_add(int i) { struct xloop_device *xlo; struct gendisk *disk; int err; err = -ENOMEM; xlo = kzalloc(sizeof(*xlo), GFP_KERNEL); if (!xlo) goto out; xlo->xlo_state = Xlo_unbound; err = mutex_lock_killable(&xloop_ctl_mutex); if (err) goto out_free_dev; /* allocate id, if @id >= 0, we're requesting that specific id */ if (i >= 0) { err = idr_alloc(&xloop_index_idr, xlo, i, i + 1, GFP_KERNEL); if (err == -ENOSPC) err = -EEXIST; } else { err = idr_alloc(&xloop_index_idr, xlo, 0, 0, GFP_KERNEL); } mutex_unlock(&xloop_ctl_mutex); if (err < 0) goto out_free_dev; i = err; err = -ENOMEM; xlo->tag_set.ops = &xloop_mq_ops; xlo->tag_set.nr_hw_queues = 1; xlo->tag_set.queue_depth = 128; xlo->tag_set.numa_node = NUMA_NO_NODE; xlo->tag_set.cmd_size = sizeof(struct xloop_cmd); xlo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING | BLK_MQ_F_NO_SCHED_BY_DEFAULT; xlo->tag_set.driver_data = xlo; err = blk_mq_alloc_tag_set(&xlo->tag_set); if (err) goto out_free_idr; disk = xlo->xlo_disk = blk_mq_alloc_disk(&xlo->tag_set, xlo); if (IS_ERR(disk)) { err = PTR_ERR(disk); goto out_cleanup_tags; } xlo->xlo_queue = xlo->xlo_disk->queue; blk_queue_max_hw_sectors(xlo->xlo_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, xlo->xlo_queue); err = -ENOMEM; xlo->xlo_fmt = xloop_file_fmt_alloc(); if (!xlo->xlo_fmt) goto out_cleanup_disk; xloop_file_fmt_set_xlo(xlo->xlo_fmt, xlo); /* * 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 xloop device numbers will continue * to match the xloop minors, regardless of the number of partitions * used. * * If max_part is given, partition scanning is globally enabled for * all xloop devices. The minors for the main xloop devices will be * multiples of max_part. * * Note: Global-for-all-devices, set-only-at-init, read-only module * parameteters like 'max_xloop' 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; #if LINUX_VERSION_CODE < KERNEL_VERSION(5, 17, 0) disk->flags |= GENHD_FL_EXT_DEVT; #endif atomic_set(&xlo->xlo_refcnt, 0); mutex_init(&xlo->xlo_mutex); xlo->xlo_number = i; spin_lock_init(&xlo->xlo_lock); spin_lock_init(&xlo->xlo_work_lock); disk->major = XLOOP_MAJOR; disk->first_minor = i << part_shift; disk->minors = 1 << part_shift; disk->fops = &xlo_fops; disk->private_data = xlo; disk->queue = xlo->xlo_queue; disk->events = DISK_EVENT_MEDIA_CHANGE; disk->event_flags = DISK_EVENT_FLAG_UEVENT; sprintf(disk->disk_name, "xloop%d", i); /* Make this xloop device reachable from pathname. */ err = add_disk(disk); if (err != 0) goto out_free_file_fmt; /* Show this xloop device. */ mutex_lock(&xloop_ctl_mutex); xlo->idr_visible = true; mutex_unlock(&xloop_ctl_mutex); /* * initialize debugfs entries * * create for each xloop device a debugfs directory under 'xloop' if * the 'block' directory exists, otherwise create the loop directory in * the root directory */ #ifdef CONFIG_DEBUG_FS xlo->xlo_dbgfs_dir = debugfs_create_dir(disk->disk_name, xloop_dbgfs_dir); if (IS_ERR_OR_NULL(xlo->xlo_dbgfs_dir)) { err = -ENODEV; xlo->xlo_dbgfs_dir = NULL; goto out_free_file_fmt; } #endif return i; out_free_file_fmt: xloop_file_fmt_free(xlo->xlo_fmt); out_cleanup_disk: #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 0, 0) put_disk(xlo->xlo_disk); #else blk_cleanup_disk(xlo->xlo_disk); #endif out_cleanup_tags: blk_mq_free_tag_set(&xlo->tag_set); out_free_idr: mutex_lock(&xloop_ctl_mutex); idr_remove(&xloop_index_idr, i); mutex_unlock(&xloop_ctl_mutex); out_free_dev: kfree(xlo); out: return err; } static void xloop_remove(struct xloop_device *xlo) { xloop_file_fmt_free(xlo->xlo_fmt); #ifdef CONFIG_DEBUG_FS debugfs_remove(xlo->xlo_dbgfs_dir); #endif /* Make this xloop device unreachable from pathname. */ del_gendisk(xlo->xlo_disk); #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 0, 0) put_disk(xlo->xlo_disk); #else blk_cleanup_disk(xlo->xlo_disk); #endif blk_mq_free_tag_set(&xlo->tag_set); mutex_lock(&xloop_ctl_mutex); idr_remove(&xloop_index_idr, xlo->xlo_number); mutex_unlock(&xloop_ctl_mutex); /* There is no route which can find this xloop device. */ mutex_destroy(&xlo->xlo_mutex); kfree(xlo); } static void xloop_probe(dev_t dev) { int idx = MINOR(dev) >> part_shift; if (max_xloop && idx >= max_xloop) return; xloop_add(idx); } static int xloop_control_remove(int idx) { struct xloop_device *xlo; int ret; if (idx < 0) { pr_warn("deleting an unspecified xloop device is not supported.\n"); return -EINVAL; } /* Hide this xloop device for serialization. */ ret = mutex_lock_killable(&xloop_ctl_mutex); if (ret) return ret; xlo = idr_find(&xloop_index_idr, idx); if (!xlo || !xlo->idr_visible) ret = -ENODEV; else xlo->idr_visible = false; mutex_unlock(&xloop_ctl_mutex); if (ret) return ret; /* Check whether this xloop device can be removed. */ ret = mutex_lock_killable(&xlo->xlo_mutex); if (ret) goto mark_visible; if (xlo->xlo_state != Xlo_unbound || atomic_read(&xlo->xlo_refcnt) > 0) { mutex_unlock(&xlo->xlo_mutex); ret = -EBUSY; goto mark_visible; } /* Mark this xloop device no longer open()-able. */ xlo->xlo_state = Xlo_deleting; mutex_unlock(&xlo->xlo_mutex); xloop_remove(xlo); return 0; mark_visible: /* Show this xloop device again. */ mutex_lock(&xloop_ctl_mutex); xlo->idr_visible = true; mutex_unlock(&xloop_ctl_mutex); return ret; } static int xloop_control_get_free(int idx) { struct xloop_device *xlo; int id, ret; ret = mutex_lock_killable(&xloop_ctl_mutex); if (ret) return ret; idr_for_each_entry(&xloop_index_idr, xlo, id) { /* Hitting a race results in creating a new xloop device which is harmless. */ if (xlo->idr_visible && data_race(xlo->xlo_state) == Xlo_unbound) goto found; } mutex_unlock(&xloop_ctl_mutex); return xloop_add(-1); found: mutex_unlock(&xloop_ctl_mutex); return id; } static long xloop_control_ioctl(struct file *file, unsigned int cmd, unsigned long parm) { switch (cmd) { case XLOOP_CTL_ADD: return xloop_add(parm); case XLOOP_CTL_REMOVE: return xloop_control_remove(parm); case XLOOP_CTL_GET_FREE: return xloop_control_get_free(parm); default: return -ENOSYS; } } static const struct file_operations xloop_ctl_fops = { .open = nonseekable_open, .unlocked_ioctl = xloop_control_ioctl, .compat_ioctl = xloop_control_ioctl, .owner = THIS_MODULE, .llseek = noop_llseek, }; static struct miscdevice xloop_misc = { .minor = XLOOP_CTRL_MINOR, .name = "xloop-control", .fops = &xloop_ctl_fops, }; MODULE_ALIAS_MISCDEV(XLOOP_CTRL_MINOR); MODULE_ALIAS("devname:xloop-control"); static int __init xloop_init(void) { int i, nr; int err; part_shift = 0; if (max_part > 0) { part_shift = fls(max_part); /* * Adjust max_part according to part_shift as it is exported * to user space so that user can decide correct minor number * if [s]he want to create more devices. * * Note that -1 is required because partition 0 is reserved * for the whole disk. */ max_part = (1UL << part_shift) - 1; } if ((1UL << part_shift) > DISK_MAX_PARTS) { err = -EINVAL; goto err_out; } if (max_xloop > 1UL << (MINORBITS - part_shift)) { err = -EINVAL; goto err_out; } /* * If max_xloop is specified, create that many devices upfront. * This also becomes a hard limit. If max_xloop is not specified, * create CONFIG_BLK_DEV_XLOOP_MIN_COUNT xloop devices at module * init time. Loop devices can be requested on-demand with the * /dev/xloop-control interface, or be instantiated by accessing * a 'dead' device node. */ if (max_xloop) nr = max_xloop; else nr = CONFIG_BLK_DEV_XLOOP_MIN_COUNT; err = misc_register(&xloop_misc); if (err < 0) goto err_out; if (__register_blkdev(XLOOP_MAJOR, "xloop", xloop_probe)) { err = -EIO; goto misc_out; } #ifdef CONFIG_DEBUG_FS xloop_dbgfs_dir = debugfs_create_dir("xloop", NULL); if (IS_ERR_OR_NULL(xloop_dbgfs_dir)) { err = -ENODEV; goto blkdev_out; } #endif /* pre-create number of devices given by config or max_xloop */ for (i = 0; i < nr; i++) xloop_add(i); pr_info("module in version %s loaded\n", XLOOP_VERSION); return 0; #ifdef CONFIG_DEBUG_FS blkdev_out: unregister_blkdev(XLOOP_MAJOR, "xloop"); #endif misc_out: misc_deregister(&xloop_misc); err_out: return err; } static void __exit xloop_exit(void) { struct xloop_device *xlo; int id; unregister_blkdev(XLOOP_MAJOR, "xloop"); misc_deregister(&xloop_misc); /* * There is no need to use xloop_ctl_mutex here, for nobody else can * access xloop_index_idr when this module is unloading (unless forced * module unloading is requested). If this is not a clean unloading, * we have no means to avoid kernel crash. */ idr_for_each_entry(&xloop_index_idr, xlo, id) xloop_remove(xlo); idr_destroy(&xloop_index_idr); #ifdef CONFIG_DEBUG_FS debugfs_remove(xloop_dbgfs_dir); #endif pr_info("exit module\n"); } module_init(xloop_init); module_exit(xloop_exit); #ifndef MODULE static int __init max_xloop_setup(char *str) { max_xloop = simple_strtol(str, NULL, 0); return 1; } __setup("max_xloop=", max_xloop_setup); #endif