--- /dev/null
+/*
+ * 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_lock prevents look up
+ * results from going away underneath its user.
+ */
+static DEFINE_SPINLOCK(ext_devt_lock);
+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_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;
+
+ /* in consecutive minor range? */
+ if (part->partno < disk->minors) {
+ *devt = MKDEV(disk->major, disk->first_minor + part->partno);
+ return 0;
+ }
+
+ /* allocate ext devt */
+ idr_preload(GFP_KERNEL);
+
+ spin_lock_bh(&ext_devt_lock);
+ idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
+ spin_unlock_bh(&ext_devt_lock);
+
+ idr_preload_end();
+ 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)
+{
+ if (devt == MKDEV(0, 0))
+ return;
+
+ if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
+ spin_lock_bh(&ext_devt_lock);
+ idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
+ spin_unlock_bh(&ext_devt_lock);
+ }
+}
+
+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;
+}
+
+static void register_disk(struct gendisk *disk)
+{
+ struct device *ddev = disk_to_dev(disk);
+ struct block_device *bdev;
+ struct disk_part_iter piter;
+ struct hd_struct *part;
+ int err;
+
+ ddev->parent = disk->driverfs_dev;
+
+ dev_set_name(ddev, "%s", disk->disk_name);
+
+ /* delay uevents, until we scanned partition table */
+ dev_set_uevent_suppress(ddev, 1);
+
+ if (device_add(ddev))
+ return;
+ if (!sysfs_deprecated) {
+ err = sysfs_create_link(block_depr, &ddev->kobj,
+ kobject_name(&ddev->kobj));
+ if (err) {
+ device_del(ddev);
+ return;
+ }
+ }
+
+ /*
+ * avoid probable deadlock caused by allocating memory with
+ * GFP_KERNEL in runtime_resume callback of its all ancestor
+ * devices
+ */
+ pm_runtime_set_memalloc_noio(ddev, true);
+
+ disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
+ disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
+
+ /* No minors to use for partitions */
+ if (!disk_part_scan_enabled(disk))
+ goto exit;
+
+ /* No such device (e.g., media were just removed) */
+ if (!get_capacity(disk))
+ goto exit;
+
+ bdev = bdget_disk(disk, 0);
+ if (!bdev)
+ goto exit;
+
+ bdev->bd_invalidated = 1;
+ err = blkdev_get(bdev, FMODE_READ, NULL);
+ if (err < 0)
+ goto exit;
+ blkdev_put(bdev, FMODE_READ);
+
+exit:
+ /* announce disk after possible partitions are created */
+ dev_set_uevent_suppress(ddev, 0);
+ kobject_uevent(&ddev->kobj, KOBJ_ADD);
+
+ /* announce possible partitions */
+ disk_part_iter_init(&piter, disk, 0);
+ while ((part = disk_part_iter_next(&piter)))
+ kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
+ disk_part_iter_exit(&piter);
+}
+
+/**
+ * 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);
+
+ disk_alloc_events(disk);
+
+ /* 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);
+
+ /*
+ * Take an extra ref on queue which will be put on disk_release()
+ * so that it sticks around as long as @disk is there.
+ */
+ WARN_ON_ONCE(!blk_get_queue(disk->queue));
+
+ retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
+ "bdi");
+ WARN_ON(retval);
+
+ disk_add_events(disk);
+}
+EXPORT_SYMBOL(add_disk);
+
+void del_gendisk(struct gendisk *disk)
+{
+ struct disk_part_iter piter;
+ struct hd_struct *part;
+
+ disk_del_events(disk);
+
+ /* invalidate stuff */
+ disk_part_iter_init(&piter, disk,
+ DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
+ while ((part = disk_part_iter_next(&piter))) {
+ invalidate_partition(disk, part->partno);
+ delete_partition(disk, part->partno);
+ }
+ disk_part_iter_exit(&piter);
+
+ invalidate_partition(disk, 0);
+ set_capacity(disk, 0);
+ disk->flags &= ~GENHD_FL_UP;
+
+ sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
+ blk_unregister_queue(disk);
+ blk_unregister_region(disk_devt(disk), disk->minors);
+
+ part_stat_set_all(&disk->part0, 0);
+ disk->part0.stamp = 0;
+
+ kobject_put(disk->part0.holder_dir);
+ kobject_put(disk->slave_dir);
+ disk->driverfs_dev = NULL;
+ if (!sysfs_deprecated)
+ sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
+ pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
+ device_del(disk_to_dev(disk));
+}
+EXPORT_SYMBOL(del_gendisk);
+
+/**
+ * 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;
+
+ spin_lock_bh(&ext_devt_lock);
+ 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);
+ }
+ spin_unlock_bh(&ext_devt_lock);
+ }
+
+ 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];
+
+ /*
+ * Don't show empty devices or things that have been
+ * suppressed
+ */
+ 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;
+
+ printk("%s%s %10llu %s %s", is_part0 ? "" : " ",
+ bdevt_str(part_devt(part), devt_buf),
+ (unsigned long long)part_nr_sects_read(part) >> 1
+ , disk_name(disk, part->partno, name_buf),
+ part->info ? part->info->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)
+{
+ void *p;
+
+ p = disk_seqf_start(seqf, pos);
+ if (!IS_ERR_OR_NULL(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_max_parts(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_read(part) >> 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
+};
+
+/**
+ * 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);
+ kfree_rcu(old_ptbl, rcu_head);
+ }
+}
+
+/**
+ * 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 i, target;
+ size_t size;
+
+ /*
+ * check for int overflow, since we can get here from blkpg_ioctl()
+ * with a user passed 'partno'.
+ */
+ target = partno + 1;
+ if (target < 0)
+ return -EINVAL;
+
+ /* 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);
+
+ blk_free_devt(dev->devt);
+ disk_release_events(disk);
+ kfree(disk->random);
+ disk_replace_part_tbl(disk, NULL);
+ free_part_stats(&disk->part0);
+ free_part_info(&disk->part0);
+ if (disk->queue)
+ blk_put_queue(disk->queue);
+ kfree(disk);
+}
+struct class block_class = {
+ .name = "block",
+};
+
+static char *block_devnode(struct device *dev, umode_t *mode,
+ kuid_t *uid, kgid_t *gid)
+{
+ 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 %lu "
+ "%u %lu %lu %lu %u %u %u %u\n",
+ MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
+ disk_name(gp, hd->partno, buf),
+ part_stat_read(hd, ios[READ]),
+ part_stat_read(hd, merges[READ]),
+ part_stat_read(hd, sectors[READ]),
+ jiffies_to_msecs(part_stat_read(hd, ticks[READ])),
+ part_stat_read(hd, ios[WRITE]),
+ part_stat_read(hd, merges[WRITE]),
+ part_stat_read(hd, sectors[WRITE]),
+ jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])),
+ 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 */
+
+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, NUMA_NO_NODE);
+}
+EXPORT_SYMBOL(alloc_disk);
+
+struct gendisk *alloc_disk_node(int minors, int node_id)
+{
+ struct gendisk *disk;
+
+ disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, 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;
+
+ /*
+ * set_capacity() and get_capacity() currently don't use
+ * seqcounter to read/update the part0->nr_sects. Still init
+ * the counter as we can read the sectors in IO submission
+ * patch using seqence counters.
+ *
+ * TODO: Ideally set_capacity() and get_capacity() should be
+ * converted to make use of bd_mutex and sequence counters.
+ */
+ seqcount_init(&disk->part0.nr_sects_seq);
+ hd_ref_init(&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));
+ }
+ 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, true);
+ bdput(bdev);
+ }
+ return res;
+}
+
+EXPORT_SYMBOL(invalidate_partition);
+
+/*
+ * Disk events - monitor disk events like media change and eject request.
+ */
+struct disk_events {
+ struct list_head node; /* all disk_event's */
+ struct gendisk *disk; /* the associated disk */
+ spinlock_t lock;
+
+ struct mutex block_mutex; /* protects blocking */
+ int block; /* event blocking depth */
+ unsigned int pending; /* events already sent out */
+ unsigned int clearing; /* events being cleared */
+
+ long poll_msecs; /* interval, -1 for default */
+ struct delayed_work dwork;
+};
+
+static const char *disk_events_strs[] = {
+ [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change",
+ [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request",
+};
+
+static char *disk_uevents[] = {
+ [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1",
+ [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1",
+};
+
+/* list of all disk_events */
+static DEFINE_MUTEX(disk_events_mutex);
+static LIST_HEAD(disk_events);
+
+/* disable in-kernel polling by default */
+static unsigned long disk_events_dfl_poll_msecs = 0;
+
+static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
+{
+ struct disk_events *ev = disk->ev;
+ long intv_msecs = 0;
+
+ /*
+ * If device-specific poll interval is set, always use it. If
+ * the default is being used, poll iff there are events which
+ * can't be monitored asynchronously.
+ */
+ if (ev->poll_msecs >= 0)
+ intv_msecs = ev->poll_msecs;
+ else if (disk->events & ~disk->async_events)
+ intv_msecs = disk_events_dfl_poll_msecs;
+
+ return msecs_to_jiffies(intv_msecs);
+}
+
+/**
+ * disk_block_events - block and flush disk event checking
+ * @disk: disk to block events for
+ *
+ * On return from this function, it is guaranteed that event checking
+ * isn't in progress and won't happen until unblocked by
+ * disk_unblock_events(). Events blocking is counted and the actual
+ * unblocking happens after the matching number of unblocks are done.
+ *
+ * Note that this intentionally does not block event checking from
+ * disk_clear_events().
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+void disk_block_events(struct gendisk *disk)
+{
+ struct disk_events *ev = disk->ev;
+ unsigned long flags;
+ bool cancel;
+
+ if (!ev)
+ return;
+
+ /*
+ * Outer mutex ensures that the first blocker completes canceling
+ * the event work before further blockers are allowed to finish.
+ */
+ mutex_lock(&ev->block_mutex);
+
+ spin_lock_irqsave(&ev->lock, flags);
+ cancel = !ev->block++;
+ spin_unlock_irqrestore(&ev->lock, flags);
+
+ if (cancel)
+ cancel_delayed_work_sync(&disk->ev->dwork);
+
+ mutex_unlock(&ev->block_mutex);
+}
+
+static void __disk_unblock_events(struct gendisk *disk, bool check_now)
+{
+ struct disk_events *ev = disk->ev;
+ unsigned long intv;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ev->lock, flags);
+
+ if (WARN_ON_ONCE(ev->block <= 0))
+ goto out_unlock;
+
+ if (--ev->block)
+ goto out_unlock;
+
+ /*
+ * Not exactly a latency critical operation, set poll timer
+ * slack to 25% and kick event check.
+ */
+ intv = disk_events_poll_jiffies(disk);
+ set_timer_slack(&ev->dwork.timer, intv / 4);
+ if (check_now)
+ queue_delayed_work(system_freezable_power_efficient_wq,
+ &ev->dwork, 0);
+ else if (intv)
+ queue_delayed_work(system_freezable_power_efficient_wq,
+ &ev->dwork, intv);
+out_unlock:
+ spin_unlock_irqrestore(&ev->lock, flags);
+}
+
+/**
+ * disk_unblock_events - unblock disk event checking
+ * @disk: disk to unblock events for
+ *
+ * Undo disk_block_events(). When the block count reaches zero, it
+ * starts events polling if configured.
+ *
+ * CONTEXT:
+ * Don't care. Safe to call from irq context.
+ */
+void disk_unblock_events(struct gendisk *disk)
+{
+ if (disk->ev)
+ __disk_unblock_events(disk, false);
+}
+
+/**
+ * disk_flush_events - schedule immediate event checking and flushing
+ * @disk: disk to check and flush events for
+ * @mask: events to flush
+ *
+ * Schedule immediate event checking on @disk if not blocked. Events in
+ * @mask are scheduled to be cleared from the driver. Note that this
+ * doesn't clear the events from @disk->ev.
+ *
+ * CONTEXT:
+ * If @mask is non-zero must be called with bdev->bd_mutex held.
+ */
+void disk_flush_events(struct gendisk *disk, unsigned int mask)
+{
+ struct disk_events *ev = disk->ev;
+
+ if (!ev)
+ return;
+
+ spin_lock_irq(&ev->lock);
+ ev->clearing |= mask;
+ if (!ev->block)
+ mod_delayed_work(system_freezable_power_efficient_wq,
+ &ev->dwork, 0);
+ spin_unlock_irq(&ev->lock);
+}
+
+/**
+ * disk_clear_events - synchronously check, clear and return pending events
+ * @disk: disk to fetch and clear events from
+ * @mask: mask of events to be fetched and cleared
+ *
+ * Disk events are synchronously checked and pending events in @mask
+ * are cleared and returned. This ignores the block count.
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
+{
+ const struct block_device_operations *bdops = disk->fops;
+ struct disk_events *ev = disk->ev;
+ unsigned int pending;
+ unsigned int clearing = mask;
+
+ if (!ev) {
+ /* for drivers still using the old ->media_changed method */
+ if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
+ bdops->media_changed && bdops->media_changed(disk))
+ return DISK_EVENT_MEDIA_CHANGE;
+ return 0;
+ }
+
+ disk_block_events(disk);
+
+ /*
+ * store the union of mask and ev->clearing on the stack so that the
+ * race with disk_flush_events does not cause ambiguity (ev->clearing
+ * can still be modified even if events are blocked).
+ */
+ spin_lock_irq(&ev->lock);
+ clearing |= ev->clearing;
+ ev->clearing = 0;
+ spin_unlock_irq(&ev->lock);
+
+ disk_check_events(ev, &clearing);
+ /*
+ * if ev->clearing is not 0, the disk_flush_events got called in the
+ * middle of this function, so we want to run the workfn without delay.
+ */
+ __disk_unblock_events(disk, ev->clearing ? true : false);
+
+ /* then, fetch and clear pending events */
+ spin_lock_irq(&ev->lock);
+ pending = ev->pending & mask;
+ ev->pending &= ~mask;
+ spin_unlock_irq(&ev->lock);
+ WARN_ON_ONCE(clearing & mask);
+
+ return pending;
+}
+
+/*
+ * Separate this part out so that a different pointer for clearing_ptr can be
+ * passed in for disk_clear_events.
+ */
+static void disk_events_workfn(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
+
+ disk_check_events(ev, &ev->clearing);
+}
+
+static void disk_check_events(struct disk_events *ev,
+ unsigned int *clearing_ptr)
+{
+ struct gendisk *disk = ev->disk;
+ char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
+ unsigned int clearing = *clearing_ptr;
+ unsigned int events;
+ unsigned long intv;
+ int nr_events = 0, i;
+
+ /* check events */
+ events = disk->fops->check_events(disk, clearing);
+
+ /* accumulate pending events and schedule next poll if necessary */
+ spin_lock_irq(&ev->lock);
+
+ events &= ~ev->pending;
+ ev->pending |= events;
+ *clearing_ptr &= ~clearing;
+
+ intv = disk_events_poll_jiffies(disk);
+ if (!ev->block && intv)
+ queue_delayed_work(system_freezable_power_efficient_wq,
+ &ev->dwork, intv);
+
+ spin_unlock_irq(&ev->lock);
+
+ /*
+ * Tell userland about new events. Only the events listed in
+ * @disk->events are reported. Unlisted events are processed the
+ * same internally but never get reported to userland.
+ */
+ for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
+ if (events & disk->events & (1 << i))
+ envp[nr_events++] = disk_uevents[i];
+
+ if (nr_events)
+ kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
+}
+
+/*
+ * A disk events enabled device has the following sysfs nodes under
+ * its /sys/block/X/ directory.
+ *
+ * events : list of all supported events
+ * events_async : list of events which can be detected w/o polling
+ * events_poll_msecs : polling interval, 0: disable, -1: system default
+ */
+static ssize_t __disk_events_show(unsigned int events, char *buf)
+{
+ const char *delim = "";
+ ssize_t pos = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
+ if (events & (1 << i)) {
+ pos += sprintf(buf + pos, "%s%s",
+ delim, disk_events_strs[i]);
+ delim = " ";
+ }
+ if (pos)
+ pos += sprintf(buf + pos, "\n");
+ return pos;
+}
+
+static ssize_t disk_events_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return __disk_events_show(disk->events, buf);
+}
+
+static ssize_t disk_events_async_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return __disk_events_show(disk->async_events, buf);
+}
+
+static ssize_t disk_events_poll_msecs_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
+}
+
+static ssize_t disk_events_poll_msecs_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ long intv;
+
+ if (!count || !sscanf(buf, "%ld", &intv))
+ return -EINVAL;
+
+ if (intv < 0 && intv != -1)
+ return -EINVAL;
+
+ disk_block_events(disk);
+ disk->ev->poll_msecs = intv;
+ __disk_unblock_events(disk, true);
+
+ return count;
+}
+
+static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL);
+static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL);
+static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR,
+ disk_events_poll_msecs_show,
+ disk_events_poll_msecs_store);
+
+static const struct attribute *disk_events_attrs[] = {
+ &dev_attr_events.attr,
+ &dev_attr_events_async.attr,
+ &dev_attr_events_poll_msecs.attr,
+ NULL,
+};
+
+/*
+ * The default polling interval can be specified by the kernel
+ * parameter block.events_dfl_poll_msecs which defaults to 0
+ * (disable). This can also be modified runtime by writing to
+ * /sys/module/block/events_dfl_poll_msecs.
+ */
+static int disk_events_set_dfl_poll_msecs(const char *val,
+ const struct kernel_param *kp)
+{
+ struct disk_events *ev;
+ int ret;
+
+ ret = param_set_ulong(val, kp);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&disk_events_mutex);
+
+ list_for_each_entry(ev, &disk_events, node)
+ disk_flush_events(ev->disk, 0);
+
+ mutex_unlock(&disk_events_mutex);
+
+ return 0;
+}
+
+static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
+ .set = disk_events_set_dfl_poll_msecs,
+ .get = param_get_ulong,
+};
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "block."
+
+module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
+ &disk_events_dfl_poll_msecs, 0644);
+
+/*
+ * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
+ */
+static void disk_alloc_events(struct gendisk *disk)
+{
+ struct disk_events *ev;
+
+ if (!disk->fops->check_events)
+ return;
+
+ ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+ if (!ev) {
+ pr_warn("%s: failed to initialize events\n", disk->disk_name);
+ return;
+ }
+
+ INIT_LIST_HEAD(&ev->node);
+ ev->disk = disk;
+ spin_lock_init(&ev->lock);
+ mutex_init(&ev->block_mutex);
+ ev->block = 1;
+ ev->poll_msecs = -1;
+ INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
+
+ disk->ev = ev;
+}
+
+static void disk_add_events(struct gendisk *disk)
+{
+ if (!disk->ev)
+ return;
+
+ /* FIXME: error handling */
+ if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
+ pr_warn("%s: failed to create sysfs files for events\n",
+ disk->disk_name);
+
+ mutex_lock(&disk_events_mutex);
+ list_add_tail(&disk->ev->node, &disk_events);
+ mutex_unlock(&disk_events_mutex);
+
+ /*
+ * Block count is initialized to 1 and the following initial
+ * unblock kicks it into action.
+ */
+ __disk_unblock_events(disk, true);
+}
+
+static void disk_del_events(struct gendisk *disk)
+{
+ if (!disk->ev)
+ return;
+
+ disk_block_events(disk);
+
+ mutex_lock(&disk_events_mutex);
+ list_del_init(&disk->ev->node);
+ mutex_unlock(&disk_events_mutex);
+
+ sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
+}
+
+static void disk_release_events(struct gendisk *disk)
+{
+ /* the block count should be 1 from disk_del_events() */
+ WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
+ kfree(disk->ev);
+}
Code Review / kvmfornfv.git / blobdiff