/*
 *  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/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 "blk.h"

static DEFINE_MUTEX(block_class_lock);
#ifndef CONFIG_SYSFS_DEPRECATED
struct kobject *block_depr;
#endif

static struct device_type disk_type;

/*
 * 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 *f, 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(f, "%3d %s\n", dp->major, dp->name);
                mutex_unlock(&block_class_lock);
        }
}
#endif /* CONFIG_PROC_FS */

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;

/*
 * 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 *part, void *data)
{
        struct gendisk *p = data;

        return &p->dev.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.
 */
void add_disk(struct gendisk *disk)
{
        disk->flags |= GENHD_FL_UP;
        blk_register_region(MKDEV(disk->major, disk->first_minor),
                            disk->minors, NULL, exact_match, exact_lock, disk);
        register_disk(disk);
        blk_register_queue(disk);
}

EXPORT_SYMBOL(add_disk);
EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */

void unlink_gendisk(struct gendisk *disk)
{
        blk_unregister_queue(disk);
        blk_unregister_region(MKDEV(disk->major, disk->first_minor),
                              disk->minors);
}

/**
 * get_gendisk - get partitioning information for a given device
 * @dev: device to get partitioning information for
 *
 * This function gets the structure containing partitioning
 * information for the given device @dev.
 */
struct gendisk *get_gendisk(dev_t devt, int *part)
{
        struct kobject *kobj = kobj_lookup(bdev_map, devt, part);
        struct device *dev = kobj_to_dev(kobj);

        return  kobj ? dev_to_disk(dev) : NULL;
}

/*
 * 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 device *dev;
        struct gendisk *sgp;
        char buf[BDEVNAME_SIZE];
        int n;

        mutex_lock(&block_class_lock);
        /* For each block device... */
        list_for_each_entry(dev, &block_class.devices, node) {
                if (dev->type != &disk_type)
                        continue;
                sgp = dev_to_disk(dev);
                /*
                 * Don't show empty devices or things that have been surpressed
                 */
                if (get_capacity(sgp) == 0 ||
                    (sgp->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.
                 */
                printk("%02x%02x %10llu %s",
                        sgp->major, sgp->first_minor,
                        (unsigned long long)get_capacity(sgp) >> 1,
                        disk_name(sgp, 0, buf));
                if (sgp->driverfs_dev != NULL &&
                    sgp->driverfs_dev->driver != NULL)
                        printk(" driver: %s\n",
                                sgp->driverfs_dev->driver->name);
                else
                        printk(" (driver?)\n");

                /* now show the partitions */
                for (n = 0; n < sgp->minors - 1; ++n) {
                        if (sgp->part[n] == NULL)
                                continue;
                        if (sgp->part[n]->nr_sects == 0)
                                continue;
                        printk("  %02x%02x %10llu %s\n",
                                sgp->major, n + 1 + sgp->first_minor,
                                (unsigned long long)sgp->part[n]->nr_sects >> 1,
                                disk_name(sgp, n + 1, buf));
                }
        }

        mutex_unlock(&block_class_lock);
}

#ifdef CONFIG_PROC_FS
/* iterator */
static void *part_start(struct seq_file *part, loff_t *pos)
{
        loff_t k = *pos;
        struct device *dev;

        mutex_lock(&block_class_lock);
        list_for_each_entry(dev, &block_class.devices, node) {
                if (dev->type != &disk_type)
                        continue;
                if (!k--)
                        return dev_to_disk(dev);
        }
        return NULL;
}

static void *part_next(struct seq_file *part, void *v, loff_t *pos)
{
        struct gendisk *gp = v;
        struct device *dev;
        ++*pos;
        list_for_each_entry(dev, &gp->dev.node, node) {
                if (&dev->node == &block_class.devices)
                        return NULL;
                if (dev->type == &disk_type)
                        return dev_to_disk(dev);
        }
        return NULL;
}

static void part_stop(struct seq_file *part, void *v)
{
        mutex_unlock(&block_class_lock);
}

static int show_partition(struct seq_file *part, void *v)
{
        struct gendisk *sgp = v;
        int n;
        char buf[BDEVNAME_SIZE];

        if (&sgp->dev.node == block_class.devices.next)
                seq_puts(part, "major minor  #blocks  name\n\n");

        /* Don't show non-partitionable removeable devices or empty devices */
        if (!get_capacity(sgp) ||
                        (sgp->minors == 1 && (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 */
        seq_printf(part, "%4d  %4d %10llu %s\n",
                sgp->major, sgp->first_minor,
                (unsigned long long)get_capacity(sgp) >> 1,
                disk_name(sgp, 0, buf));
        for (n = 0; n < sgp->minors - 1; n++) {
                if (!sgp->part[n])
                        continue;
                if (sgp->part[n]->nr_sects == 0)
                        continue;
                seq_printf(part, "%4d  %4d %10llu %s\n",
                        sgp->major, n + 1 + sgp->first_minor,
                        (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
                        disk_name(sgp, n + 1, buf));
        }

        return 0;
}

const struct seq_operations partitions_op = {
        .start  = part_start,
        .next   = part_next,
        .stop   = part_stop,
        .show   = show_partition
};
#endif


static struct kobject *base_probe(dev_t devt, int *part, 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 = class_register(&block_class);
        if (unlikely(error))
                return error;
        bdev_map = kobj_map_init(base_probe, &block_class_lock);
        blk_dev_init();

#ifndef CONFIG_SYSFS_DEPRECATED
        /* create top-level block dir */
        block_depr = kobject_create_and_add("block", NULL);
#endif
        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_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_size_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct gendisk *disk = dev_to_disk(dev);

        return sprintf(buf, "%llu\n", (unsigned long long)get_capacity(disk));
}

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_stat_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct gendisk *disk = dev_to_disk(dev);

        preempt_disable();
        disk_round_stats(disk);
        preempt_enable();
        return sprintf(buf,
                "%8lu %8lu %8llu %8u "
                "%8lu %8lu %8llu %8u "
                "%8u %8u %8u"
                "\n",
                disk_stat_read(disk, ios[READ]),
                disk_stat_read(disk, merges[READ]),
                (unsigned long long)disk_stat_read(disk, sectors[READ]),
                jiffies_to_msecs(disk_stat_read(disk, ticks[READ])),
                disk_stat_read(disk, ios[WRITE]),
                disk_stat_read(disk, merges[WRITE]),
                (unsigned long long)disk_stat_read(disk, sectors[WRITE]),
                jiffies_to_msecs(disk_stat_read(disk, ticks[WRITE])),
                disk->in_flight,
                jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
                jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
}

#ifdef CONFIG_FAIL_MAKE_REQUEST
static ssize_t disk_fail_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_FAIL ? 1 : 0);
}

static ssize_t disk_fail_store(struct device *dev,
                               struct device_attribute *attr,
                               const char *buf, size_t count)
{
        struct gendisk *disk = dev_to_disk(dev);
        int i;

        if (count > 0 && sscanf(buf, "%d", &i) > 0) {
                if (i == 0)
                        disk->flags &= ~GENHD_FL_FAIL;
                else
                        disk->flags |= GENHD_FL_FAIL;
        }

        return count;
}

#endif

static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, disk_size_show, NULL);
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, disk_stat_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
        __ATTR(make-it-fail, S_IRUGO|S_IWUSR, disk_fail_show, disk_fail_store);
#endif

static struct attribute *disk_attrs[] = {
        &dev_attr_range.attr,
        &dev_attr_removable.attr,
        &dev_attr_size.attr,
        &dev_attr_capability.attr,
        &dev_attr_stat.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
        &dev_attr_fail.attr,
#endif
        NULL
};

static struct attribute_group disk_attr_group = {
        .attrs = disk_attrs,
};

static struct attribute_group *disk_attr_groups[] = {
        &disk_attr_group,
        NULL
};

static void disk_release(struct device *dev)
{
        struct gendisk *disk = dev_to_disk(dev);

        kfree(disk->random);
        kfree(disk->part);
        free_disk_stats(disk);
        kfree(disk);
}
struct class block_class = {
        .name           = "block",
};

static struct device_type disk_type = {
        .name           = "disk",
        .groups         = disk_attr_groups,
        .release        = disk_release,
};

/*
 * 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 void *diskstats_start(struct seq_file *part, loff_t *pos)
{
        loff_t k = *pos;
        struct device *dev;

        mutex_lock(&block_class_lock);
        list_for_each_entry(dev, &block_class.devices, node) {
                if (dev->type != &disk_type)
                        continue;
                if (!k--)
                        return dev_to_disk(dev);
        }
        return NULL;
}

static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
{
        struct gendisk *gp = v;
        struct device *dev;

        ++*pos;
        list_for_each_entry(dev, &gp->dev.node, node) {
                if (&dev->node == &block_class.devices)
                        return NULL;
                if (dev->type == &disk_type)
                        return dev_to_disk(dev);
        }
        return NULL;
}

static void diskstats_stop(struct seq_file *part, void *v)
{
        mutex_unlock(&block_class_lock);
}

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

        /*
        if (&gp->dev.kobj.entry == block_class.devices.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 %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
                gp->major, n + gp->first_minor, disk_name(gp, n, buf),
                disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
                (unsigned long long)disk_stat_read(gp, sectors[0]),
                jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
                disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
                (unsigned long long)disk_stat_read(gp, sectors[1]),
                jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
                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)
                        continue;

                preempt_disable();
                part_round_stats(hd);
                preempt_enable();
                seq_printf(s, "%4d %4d %s %lu %lu %llu "
                           "%u %lu %lu %llu %u %u %u %u\n",
                           gp->major, n + gp->first_minor + 1,
                           disk_name(gp, n + 1, 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])),
                           hd->in_flight,
                           jiffies_to_msecs(part_stat_read(hd, io_ticks)),
                           jiffies_to_msecs(part_stat_read(hd, time_in_queue))
                        );
        }
 
        return 0;
}

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

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(&gd->dev.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)
{
        struct device *dev;
        dev_t devt = MKDEV(0, 0);

        mutex_lock(&block_class_lock);
        list_for_each_entry(dev, &block_class.devices, node) {
                if (strcmp(dev->bus_id, name) == 0) {
                        devt = dev->devt;
                        break;
                }
        }
        mutex_unlock(&block_class_lock);

        return devt;
}

EXPORT_SYMBOL(blk_lookup_devt);

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 | __GFP_ZERO, node_id);
        if (disk) {
                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 | __GFP_ZERO, node_id);
                        if (!disk->part) {
                                free_disk_stats(disk);
                                kfree(disk);
                                return NULL;
                        }
                }
                disk->minors = minors;
                rand_initialize_disk(disk);
                disk->dev.class = &block_class;
                disk->dev.type = &disk_type;
                device_initialize(&disk->dev);
                INIT_WORK(&disk->async_notify,
                        media_change_notify_thread);
        }
        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->dev.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->dev.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);