/* * gendisk handling */ #include <linux/module.h> #include <linux/fs.h> #include <linux/genhd.h> #include <linux/kdev_t.h> #include <linux/kernel.h> #include <linux/blkdev.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/kmod.h> #include <linux/kobj_map.h> #include <linux/buffer_head.h> #include <linux/mutex.h> #include <linux/idr.h> #include "blk.h" static DEFINE_MUTEX(block_class_lock); struct kobject *block_depr; /* for extended dynamic devt allocation, currently only one major is used */ #define MAX_EXT_DEVT (1 << MINORBITS) /* For extended devt allocation. ext_devt_mutex prevents look up * results from going away underneath its user. */ static DEFINE_MUTEX(ext_devt_mutex); static DEFINE_IDR(ext_devt_idr); static struct device_type disk_type; /** * disk_get_part - get partition * @disk: disk to look partition from * @partno: partition number * * Look for partition @partno from @disk. If found, increment * reference count and return it. * * CONTEXT: * Don't care. * * RETURNS: * Pointer to the found partition on success, NULL if not found. */ struct hd_struct *disk_get_part(struct gendisk *disk, int partno) { struct hd_struct *part = NULL; struct disk_part_tbl *ptbl; if (unlikely(partno < 0)) return NULL; rcu_read_lock(); ptbl = rcu_dereference(disk->part_tbl); if (likely(partno < ptbl->len)) { part = rcu_dereference(ptbl->part[partno]); if (part) get_device(part_to_dev(part)); } rcu_read_unlock(); return part; } EXPORT_SYMBOL_GPL(disk_get_part); /** * disk_part_iter_init - initialize partition iterator * @piter: iterator to initialize * @disk: disk to iterate over * @flags: DISK_PITER_* flags * * Initialize @piter so that it iterates over partitions of @disk. * * CONTEXT: * Don't care. */ void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, unsigned int flags) { struct disk_part_tbl *ptbl; rcu_read_lock(); ptbl = rcu_dereference(disk->part_tbl); piter->disk = disk; piter->part = NULL; if (flags & DISK_PITER_REVERSE) piter->idx = ptbl->len - 1; else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0)) piter->idx = 0; else piter->idx = 1; piter->flags = flags; rcu_read_unlock(); } EXPORT_SYMBOL_GPL(disk_part_iter_init); /** * disk_part_iter_next - proceed iterator to the next partition and return it * @piter: iterator of interest * * Proceed @piter to the next partition and return it. * * CONTEXT: * Don't care. */ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) { struct disk_part_tbl *ptbl; int inc, end; /* put the last partition */ disk_put_part(piter->part); piter->part = NULL; /* get part_tbl */ rcu_read_lock(); ptbl = rcu_dereference(piter->disk->part_tbl); /* determine iteration parameters */ if (piter->flags & DISK_PITER_REVERSE) { inc = -1; if (piter->flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0)) end = -1; else end = 0; } else { inc = 1; end = ptbl->len; } /* iterate to the next partition */ for (; piter->idx != end; piter->idx += inc) { struct hd_struct *part; part = rcu_dereference(ptbl->part[piter->idx]); if (!part) continue; if (!part->nr_sects && !(piter->flags & DISK_PITER_INCL_EMPTY) && !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && piter->idx == 0)) continue; get_device(part_to_dev(part)); piter->part = part; piter->idx += inc; break; } rcu_read_unlock(); return piter->part; } EXPORT_SYMBOL_GPL(disk_part_iter_next); /** * disk_part_iter_exit - finish up partition iteration * @piter: iter of interest * * Called when iteration is over. Cleans up @piter. * * CONTEXT: * Don't care. */ void disk_part_iter_exit(struct disk_part_iter *piter) { disk_put_part(piter->part); piter->part = NULL; } EXPORT_SYMBOL_GPL(disk_part_iter_exit); static inline int sector_in_part(struct hd_struct *part, sector_t sector) { return part->start_sect <= sector && sector < part->start_sect + part->nr_sects; } /** * disk_map_sector_rcu - map sector to partition * @disk: gendisk of interest * @sector: sector to map * * Find out which partition @sector maps to on @disk. This is * primarily used for stats accounting. * * CONTEXT: * RCU read locked. The returned partition pointer is valid only * while preemption is disabled. * * RETURNS: * Found partition on success, part0 is returned if no partition matches */ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) { struct disk_part_tbl *ptbl; struct hd_struct *part; int i; ptbl = rcu_dereference(disk->part_tbl); part = rcu_dereference(ptbl->last_lookup); if (part && sector_in_part(part, sector)) return part; for (i = 1; i < ptbl->len; i++) { part = rcu_dereference(ptbl->part[i]); if (part && sector_in_part(part, sector)) { rcu_assign_pointer(ptbl->last_lookup, part); return part; } } return &disk->part0; } EXPORT_SYMBOL_GPL(disk_map_sector_rcu); /* * Can be deleted altogether. Later. * */ static struct blk_major_name { struct blk_major_name *next; int major; char name[16]; } *major_names[BLKDEV_MAJOR_HASH_SIZE]; /* index in the above - for now: assume no multimajor ranges */ static inline int major_to_index(int major) { return major % BLKDEV_MAJOR_HASH_SIZE; } #ifdef CONFIG_PROC_FS void blkdev_show(struct seq_file *seqf, off_t offset) { struct blk_major_name *dp; if (offset < BLKDEV_MAJOR_HASH_SIZE) { mutex_lock(&block_class_lock); for (dp = major_names[offset]; dp; dp = dp->next) seq_printf(seqf, "%3d %s\n", dp->major, dp->name); mutex_unlock(&block_class_lock); } } #endif /* CONFIG_PROC_FS */ /** * register_blkdev - register a new block device * * @major: the requested major device number [1..255]. If @major=0, try to * allocate any unused major number. * @name: the name of the new block device as a zero terminated string * * The @name must be unique within the system. * * The return value depends on the @major input parameter. * - if a major device number was requested in range [1..255] then the * function returns zero on success, or a negative error code * - if any unused major number was requested with @major=0 parameter * then the return value is the allocated major number in range * [1..255] or a negative error code otherwise */ int register_blkdev(unsigned int major, const char *name) { struct blk_major_name **n, *p; int index, ret = 0; mutex_lock(&block_class_lock); /* temporary */ if (major == 0) { for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { if (major_names[index] == NULL) break; } if (index == 0) { printk("register_blkdev: failed to get major for %s\n", name); ret = -EBUSY; goto out; } major = index; ret = major; } p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); if (p == NULL) { ret = -ENOMEM; goto out; } p->major = major; strlcpy(p->name, name, sizeof(p->name)); p->next = NULL; index = major_to_index(major); for (n = &major_names[index]; *n; n = &(*n)->next) { if ((*n)->major == major) break; } if (!*n) *n = p; else ret = -EBUSY; if (ret < 0) { printk("register_blkdev: cannot get major %d for %s\n", major, name); kfree(p); } out: mutex_unlock(&block_class_lock); return ret; } EXPORT_SYMBOL(register_blkdev); void unregister_blkdev(unsigned int major, const char *name) { struct blk_major_name **n; struct blk_major_name *p = NULL; int index = major_to_index(major); mutex_lock(&block_class_lock); for (n = &major_names[index]; *n; n = &(*n)->next) if ((*n)->major == major) break; if (!*n || strcmp((*n)->name, name)) { WARN_ON(1); } else { p = *n; *n = p->next; } mutex_unlock(&block_class_lock); kfree(p); } EXPORT_SYMBOL(unregister_blkdev); static struct kobj_map *bdev_map; /** * blk_mangle_minor - scatter minor numbers apart * @minor: minor number to mangle * * Scatter consecutively allocated @minor number apart if MANGLE_DEVT * is enabled. Mangling twice gives the original value. * * RETURNS: * Mangled value. * * CONTEXT: * Don't care. */ static int blk_mangle_minor(int minor) { #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT int i; for (i = 0; i < MINORBITS / 2; i++) { int low = minor & (1 << i); int high = minor & (1 << (MINORBITS - 1 - i)); int distance = MINORBITS - 1 - 2 * i; minor ^= low | high; /* clear both bits */ low <<= distance; /* swap the positions */ high >>= distance; minor |= low | high; /* and set */ } #endif return minor; } /** * blk_alloc_devt - allocate a dev_t for a partition * @part: partition to allocate dev_t for * @devt: out parameter for resulting dev_t * * Allocate a dev_t for block device. * * RETURNS: * 0 on success, allocated dev_t is returned in *@devt. -errno on * failure. * * CONTEXT: * Might sleep. */ int blk_alloc_devt(struct hd_struct *part, dev_t *devt) { struct gendisk *disk = part_to_disk(part); int idx, rc; /* in consecutive minor range? */ if (part->partno < disk->minors) { *devt = MKDEV(disk->major, disk->first_minor + part->partno); return 0; } /* allocate ext devt */ do { if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL)) return -ENOMEM; rc = idr_get_new(&ext_devt_idr, part, &idx); } while (rc == -EAGAIN); if (rc) return rc; if (idx > MAX_EXT_DEVT) { idr_remove(&ext_devt_idr, idx); return -EBUSY; } *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx)); return 0; } /** * blk_free_devt - free a dev_t * @devt: dev_t to free * * Free @devt which was allocated using blk_alloc_devt(). * * CONTEXT: * Might sleep. */ void blk_free_devt(dev_t devt) { might_sleep(); if (devt == MKDEV(0, 0)) return; if (MAJOR(devt) == BLOCK_EXT_MAJOR) { mutex_lock(&ext_devt_mutex); idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); mutex_unlock(&ext_devt_mutex); } } static char *bdevt_str(dev_t devt, char *buf) { if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { char tbuf[BDEVT_SIZE]; snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt)); snprintf(buf, BDEVT_SIZE, "%-9s", tbuf); } else snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt)); return buf; } /* * Register device numbers dev..(dev+range-1) * range must be nonzero * The hash chain is sorted on range, so that subranges can override. */ void blk_register_region(dev_t devt, unsigned long range, struct module *module, struct kobject *(*probe)(dev_t, int *, void *), int (*lock)(dev_t, void *), void *data) { kobj_map(bdev_map, devt, range, module, probe, lock, data); } EXPORT_SYMBOL(blk_register_region); void blk_unregister_region(dev_t devt, unsigned long range) { kobj_unmap(bdev_map, devt, range); } EXPORT_SYMBOL(blk_unregister_region); static struct kobject *exact_match(dev_t devt, int *partno, void *data) { struct gendisk *p = data; return &disk_to_dev(p)->kobj; } static int exact_lock(dev_t devt, void *data) { struct gendisk *p = data; if (!get_disk(p)) return -1; return 0; } /** * add_disk - add partitioning information to kernel list * @disk: per-device partitioning information * * This function registers the partitioning information in @disk * with the kernel. * * FIXME: error handling */ void add_disk(struct gendisk *disk) { struct backing_dev_info *bdi; dev_t devt; int retval; /* minors == 0 indicates to use ext devt from part0 and should * be accompanied with EXT_DEVT flag. Make sure all * parameters make sense. */ WARN_ON(disk->minors && !(disk->major || disk->first_minor)); WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT)); disk->flags |= GENHD_FL_UP; retval = blk_alloc_devt(&disk->part0, &devt); if (retval) { WARN_ON(1); return; } disk_to_dev(disk)->devt = devt; /* ->major and ->first_minor aren't supposed to be * dereferenced from here on, but set them just in case. */ disk->major = MAJOR(devt); disk->first_minor = MINOR(devt); /* Register BDI before referencing it from bdev */ bdi = &disk->queue->backing_dev_info; bdi_register_dev(bdi, disk_devt(disk)); blk_register_region(disk_devt(disk), disk->minors, NULL, exact_match, exact_lock, disk); register_disk(disk); blk_register_queue(disk); retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, "bdi"); WARN_ON(retval); } EXPORT_SYMBOL(add_disk); EXPORT_SYMBOL(del_gendisk); /* in partitions/check.c */ void unlink_gendisk(struct gendisk *disk) { sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); bdi_unregister(&disk->queue->backing_dev_info); blk_unregister_queue(disk); blk_unregister_region(disk_devt(disk), disk->minors); } /** * get_gendisk - get partitioning information for a given device * @devt: device to get partitioning information for * @partno: returned partition index * * This function gets the structure containing partitioning * information for the given device @devt. */ struct gendisk *get_gendisk(dev_t devt, int *partno) { struct gendisk *disk = NULL; if (MAJOR(devt) != BLOCK_EXT_MAJOR) { struct kobject *kobj; kobj = kobj_lookup(bdev_map, devt, partno); if (kobj) disk = dev_to_disk(kobj_to_dev(kobj)); } else { struct hd_struct *part; mutex_lock(&ext_devt_mutex); part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); if (part && get_disk(part_to_disk(part))) { *partno = part->partno; disk = part_to_disk(part); } mutex_unlock(&ext_devt_mutex); } return disk; } EXPORT_SYMBOL(get_gendisk); /** * bdget_disk - do bdget() by gendisk and partition number * @disk: gendisk of interest * @partno: partition number * * Find partition @partno from @disk, do bdget() on it. * * CONTEXT: * Don't care. * * RETURNS: * Resulting block_device on success, NULL on failure. */ struct block_device *bdget_disk(struct gendisk *disk, int partno) { struct hd_struct *part; struct block_device *bdev = NULL; part = disk_get_part(disk, partno); if (part) bdev = bdget(part_devt(part)); disk_put_part(part); return bdev; } EXPORT_SYMBOL(bdget_disk); /* * print a full list of all partitions - intended for places where the root * filesystem can't be mounted and thus to give the victim some idea of what * went wrong */ void __init printk_all_partitions(void) { struct class_dev_iter iter; struct device *dev; class_dev_iter_init(&iter, &block_class, NULL, &disk_type); while ((dev = class_dev_iter_next(&iter))) { struct gendisk *disk = dev_to_disk(dev); struct disk_part_iter piter; struct hd_struct *part; char name_buf[BDEVNAME_SIZE]; char devt_buf[BDEVT_SIZE]; u8 uuid[PARTITION_META_INFO_UUIDLTH * 2 + 1]; /* * Don't show empty devices or things that have been * surpressed */ if (get_capacity(disk) == 0 || (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)) continue; /* * Note, unlike /proc/partitions, I am showing the * numbers in hex - the same format as the root= * option takes. */ disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0); while ((part = disk_part_iter_next(&piter))) { bool is_part0 = part == &disk->part0; uuid[0] = 0; if (part->info) part_unpack_uuid(part->info->uuid, uuid); printk("%s%s %10llu %s %s", is_part0 ? "" : " ", bdevt_str(part_devt(part), devt_buf), (unsigned long long)part->nr_sects >> 1, disk_name(disk, part->partno, name_buf), uuid); if (is_part0) { if (disk->driverfs_dev != NULL && disk->driverfs_dev->driver != NULL) printk(" driver: %s\n", disk->driverfs_dev->driver->name); else printk(" (driver?)\n"); } else printk("\n"); } disk_part_iter_exit(&piter); } class_dev_iter_exit(&iter); } #ifdef CONFIG_PROC_FS /* iterator */ static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos) { loff_t skip = *pos; struct class_dev_iter *iter; struct device *dev; iter = kmalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return ERR_PTR(-ENOMEM); seqf->private = iter; class_dev_iter_init(iter, &block_class, NULL, &disk_type); do { dev = class_dev_iter_next(iter); if (!dev) return NULL; } while (skip--); return dev_to_disk(dev); } static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos) { struct device *dev; (*pos)++; dev = class_dev_iter_next(seqf->private); if (dev) return dev_to_disk(dev); return NULL; } static void disk_seqf_stop(struct seq_file *seqf, void *v) { struct class_dev_iter *iter = seqf->private; /* stop is called even after start failed :-( */ if (iter) { class_dev_iter_exit(iter); kfree(iter); } } static void *show_partition_start(struct seq_file *seqf, loff_t *pos) { static void *p; p = disk_seqf_start(seqf, pos); if (!IS_ERR(p) && p && !*pos) seq_puts(seqf, "major minor #blocks name\n\n"); return p; } static int show_partition(struct seq_file *seqf, void *v) { struct gendisk *sgp = v; struct disk_part_iter piter; struct hd_struct *part; char buf[BDEVNAME_SIZE]; /* Don't show non-partitionable removeable devices or empty devices */ if (!get_capacity(sgp) || (!disk_partitionable(sgp) && (sgp->flags & GENHD_FL_REMOVABLE))) return 0; if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO) return 0; /* show the full disk and all non-0 size partitions of it */ disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0); while ((part = disk_part_iter_next(&piter))) seq_printf(seqf, "%4d %7d %10llu %s\n", MAJOR(part_devt(part)), MINOR(part_devt(part)), (unsigned long long)part->nr_sects >> 1, disk_name(sgp, part->partno, buf)); disk_part_iter_exit(&piter); return 0; } static const struct seq_operations partitions_op = { .start = show_partition_start, .next = disk_seqf_next, .stop = disk_seqf_stop, .show = show_partition }; static int partitions_open(struct inode *inode, struct file *file) { return seq_open(file, &partitions_op); } static const struct file_operations proc_partitions_operations = { .open = partitions_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; #endif static struct kobject *base_probe(dev_t devt, int *partno, void *data) { if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) /* Make old-style 2.4 aliases work */ request_module("block-major-%d", MAJOR(devt)); return NULL; } static int __init genhd_device_init(void) { int error; block_class.dev_kobj = sysfs_dev_block_kobj; error = class_register(&block_class); if (unlikely(error)) return error; bdev_map = kobj_map_init(base_probe, &block_class_lock); blk_dev_init(); register_blkdev(BLOCK_EXT_MAJOR, "blkext"); /* create top-level block dir */ if (!sysfs_deprecated) block_depr = kobject_create_and_add("block", NULL); return 0; } subsys_initcall(genhd_device_init); static ssize_t disk_range_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", disk->minors); } static ssize_t disk_ext_range_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", disk_max_parts(disk)); } static ssize_t disk_removable_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); } static ssize_t disk_ro_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0); } static ssize_t disk_capability_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%x\n", disk->flags); } static ssize_t disk_alignment_offset_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue)); } static ssize_t disk_discard_alignment_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue)); } static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL); static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL); static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL); static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL); static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL); static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL); static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show, NULL); static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL); static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL); static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL); #ifdef CONFIG_FAIL_MAKE_REQUEST static struct device_attribute dev_attr_fail = __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store); #endif #ifdef CONFIG_FAIL_IO_TIMEOUT static struct device_attribute dev_attr_fail_timeout = __ATTR(io-timeout-fail, S_IRUGO|S_IWUSR, part_timeout_show, part_timeout_store); #endif static struct attribute *disk_attrs[] = { &dev_attr_range.attr, &dev_attr_ext_range.attr, &dev_attr_removable.attr, &dev_attr_ro.attr, &dev_attr_size.attr, &dev_attr_alignment_offset.attr, &dev_attr_discard_alignment.attr, &dev_attr_capability.attr, &dev_attr_stat.attr, &dev_attr_inflight.attr, #ifdef CONFIG_FAIL_MAKE_REQUEST &dev_attr_fail.attr, #endif #ifdef CONFIG_FAIL_IO_TIMEOUT &dev_attr_fail_timeout.attr, #endif NULL }; static struct attribute_group disk_attr_group = { .attrs = disk_attrs, }; static const struct attribute_group *disk_attr_groups[] = { &disk_attr_group, NULL }; static void disk_free_ptbl_rcu_cb(struct rcu_head *head) { struct disk_part_tbl *ptbl = container_of(head, struct disk_part_tbl, rcu_head); kfree(ptbl); } /** * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way * @disk: disk to replace part_tbl for * @new_ptbl: new part_tbl to install * * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The * original ptbl is freed using RCU callback. * * LOCKING: * Matching bd_mutx locked. */ static void disk_replace_part_tbl(struct gendisk *disk, struct disk_part_tbl *new_ptbl) { struct disk_part_tbl *old_ptbl = disk->part_tbl; rcu_assign_pointer(disk->part_tbl, new_ptbl); if (old_ptbl) { rcu_assign_pointer(old_ptbl->last_lookup, NULL); call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb); } } /** * disk_expand_part_tbl - expand disk->part_tbl * @disk: disk to expand part_tbl for * @partno: expand such that this partno can fit in * * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl * uses RCU to allow unlocked dereferencing for stats and other stuff. * * LOCKING: * Matching bd_mutex locked, might sleep. * * RETURNS: * 0 on success, -errno on failure. */ int disk_expand_part_tbl(struct gendisk *disk, int partno) { struct disk_part_tbl *old_ptbl = disk->part_tbl; struct disk_part_tbl *new_ptbl; int len = old_ptbl ? old_ptbl->len : 0; int target = partno + 1; size_t size; int i; /* disk_max_parts() is zero during initialization, ignore if so */ if (disk_max_parts(disk) && target > disk_max_parts(disk)) return -EINVAL; if (target <= len) return 0; size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]); new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id); if (!new_ptbl) return -ENOMEM; new_ptbl->len = target; for (i = 0; i < len; i++) rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]); disk_replace_part_tbl(disk, new_ptbl); return 0; } static void disk_release(struct device *dev) { struct gendisk *disk = dev_to_disk(dev); kfree(disk->random); disk_replace_part_tbl(disk, NULL); free_part_stats(&disk->part0); free_part_info(&disk->part0); kfree(disk); } struct class block_class = { .name = "block", }; static char *block_devnode(struct device *dev, mode_t *mode) { struct gendisk *disk = dev_to_disk(dev); if (disk->devnode) return disk->devnode(disk, mode); return NULL; } static struct device_type disk_type = { .name = "disk", .groups = disk_attr_groups, .release = disk_release, .devnode = block_devnode, }; #ifdef CONFIG_PROC_FS /* * aggregate disk stat collector. Uses the same stats that the sysfs * entries do, above, but makes them available through one seq_file. * * The output looks suspiciously like /proc/partitions with a bunch of * extra fields. */ static int diskstats_show(struct seq_file *seqf, void *v) { struct gendisk *gp = v; struct disk_part_iter piter; struct hd_struct *hd; char buf[BDEVNAME_SIZE]; int cpu; /* if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) seq_puts(seqf, "major minor name" " rio rmerge rsect ruse wio wmerge " "wsect wuse running use aveq" "\n\n"); */ disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0); while ((hd = disk_part_iter_next(&piter))) { cpu = part_stat_lock(); part_round_stats(cpu, hd); part_stat_unlock(); seq_printf(seqf, "%4d %7d %s %lu %lu %llu " "%u %lu %lu %llu %u %u %u %u\n", MAJOR(part_devt(hd)), MINOR(part_devt(hd)), disk_name(gp, hd->partno, buf), part_stat_read(hd, ios[0]), part_stat_read(hd, merges[0]), (unsigned long long)part_stat_read(hd, sectors[0]), jiffies_to_msecs(part_stat_read(hd, ticks[0])), part_stat_read(hd, ios[1]), part_stat_read(hd, merges[1]), (unsigned long long)part_stat_read(hd, sectors[1]), jiffies_to_msecs(part_stat_read(hd, ticks[1])), part_in_flight(hd), jiffies_to_msecs(part_stat_read(hd, io_ticks)), jiffies_to_msecs(part_stat_read(hd, time_in_queue)) ); } disk_part_iter_exit(&piter); return 0; } static const struct seq_operations diskstats_op = { .start = disk_seqf_start, .next = disk_seqf_next, .stop = disk_seqf_stop, .show = diskstats_show }; static int diskstats_open(struct inode *inode, struct file *file) { return seq_open(file, &diskstats_op); } static const struct file_operations proc_diskstats_operations = { .open = diskstats_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; static int __init proc_genhd_init(void) { proc_create("diskstats", 0, NULL, &proc_diskstats_operations); proc_create("partitions", 0, NULL, &proc_partitions_operations); return 0; } module_init(proc_genhd_init); #endif /* CONFIG_PROC_FS */ static void media_change_notify_thread(struct work_struct *work) { struct gendisk *gd = container_of(work, struct gendisk, async_notify); char event[] = "MEDIA_CHANGE=1"; char *envp[] = { event, NULL }; /* * set enviroment vars to indicate which event this is for * so that user space will know to go check the media status. */ kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); put_device(gd->driverfs_dev); } #if 0 void genhd_media_change_notify(struct gendisk *disk) { get_device(disk->driverfs_dev); schedule_work(&disk->async_notify); } EXPORT_SYMBOL_GPL(genhd_media_change_notify); #endif /* 0 */ dev_t blk_lookup_devt(const char *name, int partno) { dev_t devt = MKDEV(0, 0); struct class_dev_iter iter; struct device *dev; class_dev_iter_init(&iter, &block_class, NULL, &disk_type); while ((dev = class_dev_iter_next(&iter))) { struct gendisk *disk = dev_to_disk(dev); struct hd_struct *part; if (strcmp(dev_name(dev), name)) continue; if (partno < disk->minors) { /* We need to return the right devno, even * if the partition doesn't exist yet. */ devt = MKDEV(MAJOR(dev->devt), MINOR(dev->devt) + partno); break; } part = disk_get_part(disk, partno); if (part) { devt = part_devt(part); disk_put_part(part); break; } disk_put_part(part); } class_dev_iter_exit(&iter); return devt; } EXPORT_SYMBOL(blk_lookup_devt); struct gendisk *alloc_disk(int minors) { return alloc_disk_node(minors, -1); } EXPORT_SYMBOL(alloc_disk); struct gendisk *alloc_disk_node(int minors, int node_id) { struct gendisk *disk; disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL | __GFP_ZERO, node_id); if (disk) { if (!init_part_stats(&disk->part0)) { kfree(disk); return NULL; } disk->node_id = node_id; if (disk_expand_part_tbl(disk, 0)) { free_part_stats(&disk->part0); kfree(disk); return NULL; } disk->part_tbl->part[0] = &disk->part0; disk->minors = minors; rand_initialize_disk(disk); disk_to_dev(disk)->class = &block_class; disk_to_dev(disk)->type = &disk_type; device_initialize(disk_to_dev(disk)); INIT_WORK(&disk->async_notify, media_change_notify_thread); } return disk; } EXPORT_SYMBOL(alloc_disk_node); struct kobject *get_disk(struct gendisk *disk) { struct module *owner; struct kobject *kobj; if (!disk->fops) return NULL; owner = disk->fops->owner; if (owner && !try_module_get(owner)) return NULL; kobj = kobject_get(&disk_to_dev(disk)->kobj); if (kobj == NULL) { module_put(owner); return NULL; } return kobj; } EXPORT_SYMBOL(get_disk); void put_disk(struct gendisk *disk) { if (disk) kobject_put(&disk_to_dev(disk)->kobj); } EXPORT_SYMBOL(put_disk); static void set_disk_ro_uevent(struct gendisk *gd, int ro) { char event[] = "DISK_RO=1"; char *envp[] = { event, NULL }; if (!ro) event[8] = '0'; kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); } void set_device_ro(struct block_device *bdev, int flag) { bdev->bd_part->policy = flag; } EXPORT_SYMBOL(set_device_ro); void set_disk_ro(struct gendisk *disk, int flag) { struct disk_part_iter piter; struct hd_struct *part; if (disk->part0.policy != flag) { set_disk_ro_uevent(disk, flag); disk->part0.policy = flag; } disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); while ((part = disk_part_iter_next(&piter))) part->policy = flag; disk_part_iter_exit(&piter); } EXPORT_SYMBOL(set_disk_ro); int bdev_read_only(struct block_device *bdev) { if (!bdev) return 0; return bdev->bd_part->policy; } EXPORT_SYMBOL(bdev_read_only); int invalidate_partition(struct gendisk *disk, int partno) { int res = 0; struct block_device *bdev = bdget_disk(disk, partno); if (bdev) { fsync_bdev(bdev); res = __invalidate_device(bdev); bdput(bdev); } return res; } EXPORT_SYMBOL(invalidate_partition);