#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 <linux/log2.h>
+#include <linux/pm_runtime.h>
#include "blk.h"
static DEFINE_MUTEX(block_class_lock);
-#ifndef CONFIG_SYSFS_DEPRECATED
struct kobject *block_depr;
-#endif
/* for extended dynamic devt allocation, currently only one major is used */
-#define MAX_EXT_DEVT (1 << MINORBITS)
+#define NR_EXT_DEVT (1 << MINORBITS)
/* For extended devt allocation. ext_devt_mutex prevents look up
* results from going away underneath its user.
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
if (flags & DISK_PITER_REVERSE)
piter->idx = ptbl->len - 1;
- else if (flags & DISK_PITER_INCL_PART0)
+ else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
piter->idx = 0;
else
piter->idx = 1;
/* determine iteration parameters */
if (piter->flags & DISK_PITER_REVERSE) {
inc = -1;
- if (piter->flags & DISK_PITER_INCL_PART0)
+ if (piter->flags & (DISK_PITER_INCL_PART0 |
+ DISK_PITER_INCL_EMPTY_PART0))
end = -1;
else
end = 0;
part = rcu_dereference(ptbl->part[piter->idx]);
if (!part)
continue;
- if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects)
+ 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));
}
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
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++) {
- struct hd_struct *part = rcu_dereference(ptbl->part[i]);
+ part = rcu_dereference(ptbl->part[i]);
- if (part && part->start_sect <= sector &&
- sector < part->start_sect + part->nr_sects)
+ if (part && sector_in_part(part, sector)) {
+ rcu_assign_pointer(ptbl->last_lookup, part);
return part;
+ }
}
return &disk->part0;
}
} *major_names[BLKDEV_MAJOR_HASH_SIZE];
/* index in the above - for now: assume no multimajor ranges */
-static inline int major_to_index(int major)
+static inline int major_to_index(unsigned major)
{
return major % BLKDEV_MAJOR_HASH_SIZE;
}
}
#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 blk_alloc_devt(struct hd_struct *part, dev_t *devt)
{
struct gendisk *disk = part_to_disk(part);
- int idx, rc;
+ int idx;
/* in consecutive minor range? */
if (part->partno < disk->minors) {
}
/* 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;
- }
+ 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;
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
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);
- bdi = &disk->queue->backing_dev_info;
- bdi_register_dev(bdi, disk_devt(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);
-EXPORT_SYMBOL(del_gendisk); /* in partitions/check.c */
-void unlink_gendisk(struct gendisk *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");
bdi_unregister(&disk->queue->backing_dev_info);
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));
+ blk_free_devt(disk_to_dev(disk)->devt);
}
+EXPORT_SYMBOL(del_gendisk);
/**
* get_gendisk - get partitioning information for a given device
return disk;
}
+EXPORT_SYMBOL(get_gendisk);
/**
* bdget_disk - do bdget() by gendisk and partition number
/*
* Don't show empty devices or things that have been
- * surpressed
+ * suppressed
*/
if (get_capacity(disk) == 0 ||
(disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
while ((part = disk_part_iter_next(&piter))) {
bool is_part0 = part == &disk->part0;
- printk("%s%s %10llu %s", is_part0 ? "" : " ",
+ 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));
+ (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)
static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
{
- static void *p;
+ void *p;
p = disk_seqf_start(seqf, pos);
- if (!IS_ERR(p) && p && !*pos)
+ if (!IS_ERR_OR_NULL(p) && !*pos)
seq_puts(seqf, "major minor #blocks name\n\n");
return p;
}
char buf[BDEVNAME_SIZE];
/* Don't show non-partitionable removeable devices or empty devices */
- if (!get_capacity(sgp) || (!disk_partitionable(sgp) &&
+ if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
(sgp->flags & GENHD_FL_REMOVABLE)))
return 0;
if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
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,
+ (unsigned long long)part_nr_sects_read(part) >> 1,
disk_name(sgp, part->partno, buf));
disk_part_iter_exit(&piter);
bdev_map = kobj_map_init(base_probe, &block_class_lock);
blk_dev_init();
-#ifndef CONFIG_SYSFS_DEPRECATED
+ register_blkdev(BLOCK_EXT_MAJOR, "blkext");
+
/* create top-level block dir */
- block_depr = kobject_create_and_add("block", NULL);
-#endif
+ if (!sysfs_deprecated)
+ block_depr = kobject_create_and_add("block", NULL);
return 0;
}
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);
&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
.attrs = disk_attrs,
};
-static struct attribute_group *disk_attr_groups[] = {
+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
struct disk_part_tbl *old_ptbl = disk->part_tbl;
rcu_assign_pointer(disk->part_tbl, new_ptbl);
- if (old_ptbl)
- call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
+
+ if (old_ptbl) {
+ rcu_assign_pointer(old_ptbl->last_lookup, NULL);
+ kfree_rcu(old_ptbl, rcu_head);
+ }
}
/**
if (!new_ptbl)
return -ENOMEM;
- INIT_RCU_HEAD(&new_ptbl->rcu_head);
new_ptbl->len = target;
for (i = 0; i < len; i++)
{
struct gendisk *disk = dev_to_disk(dev);
+ 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);
}
+
+static int disk_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ struct disk_part_iter piter;
+ struct hd_struct *part;
+ int cnt = 0;
+
+ disk_part_iter_init(&piter, disk, 0);
+ while((part = disk_part_iter_next(&piter)))
+ cnt++;
+ disk_part_iter_exit(&piter);
+ add_uevent_var(env, "NPARTS=%u", cnt);
+ return 0;
+}
+
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,
+ .uevent = disk_uevent,
};
#ifdef CONFIG_PROC_FS
"wsect wuse running use aveq"
"\n\n");
*/
-
- disk_part_iter_init(&piter, gp, DISK_PITER_INCL_PART0);
+
+ 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",
+ 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[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,
+ 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;
}
-const struct seq_operations diskstats_op = {
+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 gendisk *disk = dev_to_disk(dev);
struct hd_struct *part;
- if (strcmp(dev->bus_id, name))
+ 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);
struct gendisk *alloc_disk(int minors)
{
- return alloc_disk_node(minors, -1);
+ return alloc_disk_node(minors, NUMA_NO_NODE);
}
EXPORT_SYMBOL(alloc_disk);
kfree(disk);
return NULL;
}
+ disk->node_id = node_id;
if (disk_expand_part_tbl(disk, 0)) {
free_part_stats(&disk->part0);
kfree(disk);
}
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));
- INIT_WORK(&disk->async_notify,
- media_change_notify_thread);
- disk->node_id = node_id;
}
return disk;
}
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;
struct disk_part_iter piter;
struct hd_struct *part;
- disk_part_iter_init(&piter, disk,
- DISK_PITER_INCL_EMPTY | DISK_PITER_INCL_PART0);
+ 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);
struct block_device *bdev = bdget_disk(disk, partno);
if (bdev) {
fsync_bdev(bdev);
- res = __invalidate_device(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_wq, &ev->dwork, 0);
+ else if (intv)
+ queue_delayed_work(system_freezable_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_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 clearted
+ *
+ * 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_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 / linux-3.10.git / blobdiff