// SPDX-License-Identifier: GPL-2.0
/*
* Block device concurrent positioning ranges.
*
* Copyright (C) 2021 Western Digital Corporation or its Affiliates.
*/
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/init.h>
#include "blk.h"
static ssize_t
blk_ia_range_sector_show(struct blk_independent_access_range *iar,
char *buf)
{
return sprintf(buf, "%llu\n", iar->sector);
}
static ssize_t
blk_ia_range_nr_sectors_show(struct blk_independent_access_range *iar,
char *buf)
{
return sprintf(buf, "%llu\n", iar->nr_sectors);
}
struct blk_ia_range_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct blk_independent_access_range *iar, char *buf);
};
static struct blk_ia_range_sysfs_entry blk_ia_range_sector_entry = {
.attr = { .name = "sector", .mode = 0444 },
.show = blk_ia_range_sector_show,
};
static struct blk_ia_range_sysfs_entry blk_ia_range_nr_sectors_entry = {
.attr = { .name = "nr_sectors", .mode = 0444 },
.show = blk_ia_range_nr_sectors_show,
};
static struct attribute *blk_ia_range_attrs[] = {
&blk_ia_range_sector_entry.attr,
&blk_ia_range_nr_sectors_entry.attr,
NULL,
};
ATTRIBUTE_GROUPS(blk_ia_range);
static ssize_t blk_ia_range_sysfs_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
struct blk_ia_range_sysfs_entry *entry =
container_of(attr, struct blk_ia_range_sysfs_entry, attr);
struct blk_independent_access_range *iar =
container_of(kobj, struct blk_independent_access_range, kobj);
return entry->show(iar, buf);
}
static const struct sysfs_ops blk_ia_range_sysfs_ops = {
.show = blk_ia_range_sysfs_show,
};
/*
* Independent access range entries are not freed individually, but alltogether
* with struct blk_independent_access_ranges and its array of ranges. Since
* kobject_add() takes a reference on the parent kobject contained in
* struct blk_independent_access_ranges, the array of independent access range
* entries cannot be freed until kobject_del() is called for all entries.
* So we do not need to do anything here, but still need this no-op release
* operation to avoid complaints from the kobject code.
*/
static void blk_ia_range_sysfs_nop_release(struct kobject *kobj)
{
}
static const struct kobj_type blk_ia_range_ktype = {
.sysfs_ops = &blk_ia_range_sysfs_ops,
.default_groups = blk_ia_range_groups,
.release = blk_ia_range_sysfs_nop_release,
};
/*
* This will be executed only after all independent access range entries are
* removed with kobject_del(), at which point, it is safe to free everything,
* including the array of ranges.
*/
static void blk_ia_ranges_sysfs_release(struct kobject *kobj)
{
struct blk_independent_access_ranges *iars =
container_of(kobj, struct blk_independent_access_ranges, kobj);
kfree(iars);
}
static const struct kobj_type blk_ia_ranges_ktype = {
.release = blk_ia_ranges_sysfs_release,
};
/**
* disk_register_independent_access_ranges - register with sysfs a set of
* independent access ranges
* @disk: Target disk
*
* Register with sysfs a set of independent access ranges for @disk.
*/
int disk_register_independent_access_ranges(struct gendisk *disk)
{
struct blk_independent_access_ranges *iars = disk->ia_ranges;
struct request_queue *q = disk->queue;
int i, ret;
lockdep_assert_held(&q->sysfs_dir_lock);
lockdep_assert_held(&q->sysfs_lock);
if (!iars)
return 0;
/*
* At this point, iars is the new set of sector access ranges that needs
* to be registered with sysfs.
*/
WARN_ON(iars->sysfs_registered);
ret = kobject_init_and_add(&iars->kobj, &blk_ia_ranges_ktype,
&disk->queue_kobj, "%s",
"independent_access_ranges");
if (ret) {
disk->ia_ranges = NULL;
kobject_put(&iars->kobj);
return ret;
}
for (i = 0; i < iars->nr_ia_ranges; i++) {
ret = kobject_init_and_add(&iars->ia_range[i].kobj,
&blk_ia_range_ktype, &iars->kobj,
"%d", i);
if (ret) {
while (--i >= 0)
kobject_del(&iars->ia_range[i].kobj);
kobject_del(&iars->kobj);
kobject_put(&iars->kobj);
return ret;
}
}
iars->sysfs_registered = true;
return 0;
}
void disk_unregister_independent_access_ranges(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
struct blk_independent_access_ranges *iars = disk->ia_ranges;
int i;
lockdep_assert_held(&q->sysfs_dir_lock);
lockdep_assert_held(&q->sysfs_lock);
if (!iars)
return;
if (iars->sysfs_registered) {
for (i = 0; i < iars->nr_ia_ranges; i++)
kobject_del(&iars->ia_range[i].kobj);
kobject_del(&iars->kobj);
kobject_put(&iars->kobj);
} else {
kfree(iars);
}
disk->ia_ranges = NULL;
}
static struct blk_independent_access_range *
disk_find_ia_range(struct blk_independent_access_ranges *iars,
sector_t sector)
{
struct blk_independent_access_range *iar;
int i;
for (i = 0; i < iars->nr_ia_ranges; i++) {
iar = &iars->ia_range[i];
if (sector >= iar->sector &&
sector < iar->sector + iar->nr_sectors)
return iar;
}
return NULL;
}
static bool disk_check_ia_ranges(struct gendisk *disk,
struct blk_independent_access_ranges *iars)
{
struct blk_independent_access_range *iar, *tmp;
sector_t capacity = get_capacity(disk);
sector_t sector = 0;
int i;
if (WARN_ON_ONCE(!iars->nr_ia_ranges))
return false;
/*
* While sorting the ranges in increasing LBA order, check that the
* ranges do not overlap, that there are no sector holes and that all
* sectors belong to one range.
*/
for (i = 0; i < iars->nr_ia_ranges; i++) {
tmp = disk_find_ia_range(iars, sector);
if (!tmp || tmp->sector != sector) {
pr_warn("Invalid non-contiguous independent access ranges\n");
return false;
}
iar = &iars->ia_range[i];
if (tmp != iar) {
swap(iar->sector, tmp->sector);
swap(iar->nr_sectors, tmp->nr_sectors);
}
sector += iar->nr_sectors;
}
if (sector != capacity) {
pr_warn("Independent access ranges do not match disk capacity\n");
return false;
}
return true;
}
static bool disk_ia_ranges_changed(struct gendisk *disk,
struct blk_independent_access_ranges *new)
{
struct blk_independent_access_ranges *old = disk->ia_ranges;
int i;
if (!old)
return true;
if (old->nr_ia_ranges != new->nr_ia_ranges)
return true;
for (i = 0; i < old->nr_ia_ranges; i++) {
if (new->ia_range[i].sector != old->ia_range[i].sector ||
new->ia_range[i].nr_sectors != old->ia_range[i].nr_sectors)
return true;
}
return false;
}
/**
* disk_alloc_independent_access_ranges - Allocate an independent access ranges
* data structure
* @disk: target disk
* @nr_ia_ranges: Number of independent access ranges
*
* Allocate a struct blk_independent_access_ranges structure with @nr_ia_ranges
* access range descriptors.
*/
struct blk_independent_access_ranges *
disk_alloc_independent_access_ranges(struct gendisk *disk, int nr_ia_ranges)
{
struct blk_independent_access_ranges *iars;
iars = kzalloc_node(struct_size(iars, ia_range, nr_ia_ranges),
GFP_KERNEL, disk->queue->node);
if (iars)
iars->nr_ia_ranges = nr_ia_ranges;
return iars;
}
EXPORT_SYMBOL_GPL(disk_alloc_independent_access_ranges);
/**
* disk_set_independent_access_ranges - Set a disk independent access ranges
* @disk: target disk
* @iars: independent access ranges structure
*
* Set the independent access ranges information of the request queue
* of @disk to @iars. If @iars is NULL and the independent access ranges
* structure already set is cleared. If there are no differences between
* @iars and the independent access ranges structure already set, @iars
* is freed.
*/
void disk_set_independent_access_ranges(struct gendisk *disk,
struct blk_independent_access_ranges *iars)
{
struct request_queue *q = disk->queue;
mutex_lock(&q->sysfs_dir_lock);
mutex_lock(&q->sysfs_lock);
if (iars && !disk_check_ia_ranges(disk, iars)) {
kfree(iars);
iars = NULL;
}
if (iars && !disk_ia_ranges_changed(disk, iars)) {
kfree(iars);
goto unlock;
}
/*
* This may be called for a registered queue. E.g. during a device
* revalidation. If that is the case, we need to unregister the old
* set of independent access ranges and register the new set. If the
* queue is not registered, registration of the device request queue
* will register the independent access ranges.
*/
disk_unregister_independent_access_ranges(disk);
disk->ia_ranges = iars;
if (blk_queue_registered(q))
disk_register_independent_access_ranges(disk);
unlock:
mutex_unlock(&q->sysfs_lock);
mutex_unlock(&q->sysfs_dir_lock);
}
EXPORT_SYMBOL_GPL(disk_set_independent_access_ranges);
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