/* *  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/mutex.h>#include <linux/idr.h>#include <linux/log2.h>#include <linux/pm_runtime.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 NR_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; static void disk_check_events(struct disk_events *ev,			      unsigned int *clearing_ptr);static void disk_alloc_events(struct gendisk *disk);static void disk_add_events(struct gendisk *disk);static void disk_del_events(struct gendisk *disk);static void disk_release_events(struct gendisk *disk); /** * 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_read(part) &&		    !(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_read(part);} /** * 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(unsigned major){	return major % BLKDEV_MAJOR_HASH_SIZE;} #ifdef CONFIG_PROC_FSvoid 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; 	/* in consecutive minor range? */	if (part->partno < disk->minors) {		*devt = MKDEV(disk->major, disk->first_minor + part->partno);		return 0;	} 	/* allocate ext devt */	mutex_lock(&ext_devt_mutex);	idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_KERNEL);	mutex_unlock(&ext_devt_mutex);	if (idx < 0)		return idx == -ENOSPC ? -EBUSY : idx; 	*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))

Lines 1–500 of 1837. Load more