genhd.c

Linux块设备驱动源码

static ssize_t disk_removable_read(struct gendisk * disk, char *page)
{
	return sprintf(page, "%d\n",
		       (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));

}
static ssize_t disk_size_read(struct gendisk * disk, char *page)
{
	return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
}

static ssize_t disk_stats_read(struct gendisk * disk, char *page)
{
	preempt_disable();
	disk_round_stats(disk);
	preempt_enable();
	return sprintf(page,
		"%8u %8u %8llu %8u "
		"%8u %8u %8llu %8u "
		"%8u %8u %8u"
		"\n",
		disk_stat_read(disk, reads), disk_stat_read(disk, read_merges),
		(unsigned long long)disk_stat_read(disk, read_sectors),
		jiffies_to_msecs(disk_stat_read(disk, read_ticks)),
		disk_stat_read(disk, writes), 
		disk_stat_read(disk, write_merges),
		(unsigned long long)disk_stat_read(disk, write_sectors),
		jiffies_to_msecs(disk_stat_read(disk, write_ticks)),
		disk->in_flight,
		jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
		jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
}
static struct disk_attribute disk_attr_dev = {
	.attr = {.name = "dev", .mode = S_IRUGO },
	.show	= disk_dev_read
};
static struct disk_attribute disk_attr_range = {
	.attr = {.name = "range", .mode = S_IRUGO },
	.show	= disk_range_read
};
static struct disk_attribute disk_attr_removable = {
	.attr = {.name = "removable", .mode = S_IRUGO },
	.show	= disk_removable_read
};
static struct disk_attribute disk_attr_size = {
	.attr = {.name = "size", .mode = S_IRUGO },
	.show	= disk_size_read
};
static struct disk_attribute disk_attr_stat = {
	.attr = {.name = "stat", .mode = S_IRUGO },
	.show	= disk_stats_read
};

static struct attribute * default_attrs[] = {
	&disk_attr_dev.attr,
	&disk_attr_range.attr,
	&disk_attr_removable.attr,
	&disk_attr_size.attr,
	&disk_attr_stat.attr,
	NULL,
};

static void disk_release(struct kobject * kobj)
{
	struct gendisk *disk = to_disk(kobj);
	kfree(disk->random);
	kfree(disk->part);
	free_disk_stats(disk);
	kfree(disk);
}

static struct kobj_type ktype_block = {
	.release	= disk_release,
	.sysfs_ops	= &disk_sysfs_ops,
	.default_attrs	= default_attrs,
};

extern struct kobj_type ktype_part;

static int block_hotplug_filter(struct kset *kset, struct kobject *kobj)
{
	struct kobj_type *ktype = get_ktype(kobj);

	return ((ktype == &ktype_block) || (ktype == &ktype_part));
}

static int block_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
			 int num_envp, char *buffer, int buffer_size)
{
	struct kobj_type *ktype = get_ktype(kobj);
	struct device *physdev;
	struct gendisk *disk;
	struct hd_struct *part;
	int length = 0;
	int i = 0;

	if (ktype == &ktype_block) {
		disk = container_of(kobj, struct gendisk, kobj);
		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
				    &length, "MINOR=%u", disk->first_minor);
	} else if (ktype == &ktype_part) {
		disk = container_of(kobj->parent, struct gendisk, kobj);
		part = container_of(kobj, struct hd_struct, kobj);
		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
				    &length, "MINOR=%u",
				    disk->first_minor + part->partno);
	} else
		return 0;

	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
			    "MAJOR=%u", disk->major);

	/* add physical device, backing this device  */
	physdev = disk->driverfs_dev;
	if (physdev) {
		char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);

		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
				    &length, "PHYSDEVPATH=%s", path);
		kfree(path);

		if (physdev->bus)
			add_hotplug_env_var(envp, num_envp, &i,
					    buffer, buffer_size, &length,
					    "PHYSDEVBUS=%s",
					    physdev->bus->name);

		if (physdev->driver)
			add_hotplug_env_var(envp, num_envp, &i,
					    buffer, buffer_size, &length,
					    "PHYSDEVDRIVER=%s",
					    physdev->driver->name);
	}

	/* terminate, set to next free slot, shrink available space */
	envp[i] = NULL;
	envp = &envp[i];
	num_envp -= i;
	buffer = &buffer[length];
	buffer_size -= length;

	return 0;
}

static struct kset_hotplug_ops block_hotplug_ops = {
	.filter		= block_hotplug_filter,
	.hotplug	= block_hotplug,
};

/* declare block_subsys. */
static decl_subsys(block, &ktype_block, &block_hotplug_ops);


/*
 * aggregate disk stat collector.  Uses the same stats that the sysfs
 * entries do, above, but makes them available through one seq_file.
 * Watching a few disks may be efficient through sysfs, but watching
 * all of them will be more efficient through this interface.
 *
 * The output looks suspiciously like /proc/partitions with a bunch of
 * extra fields.
 */

/* iterator */
static void *diskstats_start(struct seq_file *part, loff_t *pos)
{
	loff_t k = *pos;
	struct list_head *p;

	down(&block_subsys_sem);
	list_for_each(p, &block_subsys.kset.list)
		if (!k--)
			return list_entry(p, struct gendisk, kobj.entry);
	return NULL;
}

static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
{
	struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
	++*pos;
	return p==&block_subsys.kset.list ? NULL :
		list_entry(p, struct gendisk, kobj.entry);
}

static void diskstats_stop(struct seq_file *part, void *v)
{
	up(&block_subsys_sem);
}

static int diskstats_show(struct seq_file *s, void *v)
{
	struct gendisk *gp = v;
	char buf[BDEVNAME_SIZE];
	int n = 0;

	/*
	if (&sgp->kobj.entry == block_subsys.kset.list.next)
		seq_puts(s,	"major minor name"
				"     rio rmerge rsect ruse wio wmerge "
				"wsect wuse running use aveq"
				"\n\n");
	*/
 
	preempt_disable();
	disk_round_stats(gp);
	preempt_enable();
	seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
		gp->major, n + gp->first_minor, disk_name(gp, n, buf),
		disk_stat_read(gp, reads), disk_stat_read(gp, read_merges),
		(unsigned long long)disk_stat_read(gp, read_sectors),
		jiffies_to_msecs(disk_stat_read(gp, read_ticks)),
		disk_stat_read(gp, writes), disk_stat_read(gp, write_merges),
		(unsigned long long)disk_stat_read(gp, write_sectors),
		jiffies_to_msecs(disk_stat_read(gp, write_ticks)),
		gp->in_flight,
		jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
		jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));

	/* now show all non-0 size partitions of it */
	for (n = 0; n < gp->minors - 1; n++) {
		struct hd_struct *hd = gp->part[n];

		if (hd && hd->nr_sects)
			seq_printf(s, "%4d %4d %s %u %u %u %u\n",
				gp->major, n + gp->first_minor + 1,
				disk_name(gp, n + 1, buf),
				hd->reads, hd->read_sectors,
				hd->writes, hd->write_sectors);
	}
 
	return 0;
}

struct seq_operations diskstats_op = {
	.start	= diskstats_start,
	.next	= diskstats_next,
	.stop	= diskstats_stop,
	.show	= diskstats_show
};

struct gendisk *alloc_disk(int minors)
{
	return alloc_disk_node(minors, -1);
}

struct gendisk *alloc_disk_node(int minors, int node_id)
{
	struct gendisk *disk;

	disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
	if (disk) {
		memset(disk, 0, sizeof(struct gendisk));
		if (!init_disk_stats(disk)) {
			kfree(disk);
			return NULL;
		}
		if (minors > 1) {
			int size = (minors - 1) * sizeof(struct hd_struct *);
			disk->part = kmalloc_node(size, GFP_KERNEL, node_id);
			if (!disk->part) {
				kfree(disk);
				return NULL;
			}
			memset(disk->part, 0, size);
		}
		disk->minors = minors;
		kobj_set_kset_s(disk,block_subsys);
		kobject_init(&disk->kobj);
		rand_initialize_disk(disk);
	}
	return disk;
}

EXPORT_SYMBOL(alloc_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->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->kobj);
}

EXPORT_SYMBOL(put_disk);

void set_device_ro(struct block_device *bdev, int flag)
{
	if (bdev->bd_contains != bdev)
		bdev->bd_part->policy = flag;
	else
		bdev->bd_disk->policy = flag;
}

EXPORT_SYMBOL(set_device_ro);

void set_disk_ro(struct gendisk *disk, int flag)
{
	int i;
	disk->policy = flag;
	for (i = 0; i < disk->minors - 1; i++)
		if (disk->part[i]) disk->part[i]->policy = flag;
}

EXPORT_SYMBOL(set_disk_ro);

int bdev_read_only(struct block_device *bdev)
{
	if (!bdev)
		return 0;
	else if (bdev->bd_contains != bdev)
		return bdev->bd_part->policy;
	else
		return bdev->bd_disk->policy;
}

EXPORT_SYMBOL(bdev_read_only);

int invalidate_partition(struct gendisk *disk, int index)
{
	int res = 0;
	struct block_device *bdev = bdget_disk(disk, index);
	if (bdev) {
		fsync_bdev(bdev);
		res = __invalidate_device(bdev);
		bdput(bdev);
	}
	return res;
}

EXPORT_SYMBOL(invalidate_partition);