[linux-block.git] / block / blk-ia-ranges.c

// 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);
Commit	Line	Data
a2247f19 DLM	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Block device concurrent positioning ranges.
	4	*
	5	* Copyright (C) 2021 Western Digital Corporation or its Affiliates.
	6	*/
	7	#include <linux/kernel.h>
	8	#include <linux/blkdev.h>
	9	#include <linux/slab.h>
	10	#include <linux/init.h>
	11
	12	#include "blk.h"
	13
	14	static ssize_t
	15	blk_ia_range_sector_show(struct blk_independent_access_range *iar,
	16	char *buf)
	17	{
	18	return sprintf(buf, "%llu\n", iar->sector);
	19	}
	20
	21	static ssize_t
	22	blk_ia_range_nr_sectors_show(struct blk_independent_access_range *iar,
	23	char *buf)
	24	{
	25	return sprintf(buf, "%llu\n", iar->nr_sectors);
	26	}
	27
	28	struct blk_ia_range_sysfs_entry {
	29	struct attribute attr;
	30	ssize_t (show)(struct blk_independent_access_range iar, char *buf);
	31	};
	32
	33	static struct blk_ia_range_sysfs_entry blk_ia_range_sector_entry = {
	34	.attr = { .name = "sector", .mode = 0444 },
	35	.show = blk_ia_range_sector_show,
	36	};
	37
	38	static struct blk_ia_range_sysfs_entry blk_ia_range_nr_sectors_entry = {
	39	.attr = { .name = "nr_sectors", .mode = 0444 },
	40	.show = blk_ia_range_nr_sectors_show,
	41	};
	42
	43	static struct attribute *blk_ia_range_attrs[] = {
	44	&blk_ia_range_sector_entry.attr,
	45	&blk_ia_range_nr_sectors_entry.attr,
	46	NULL,
	47	};
	48	ATTRIBUTE_GROUPS(blk_ia_range);
	49
	50	static ssize_t blk_ia_range_sysfs_show(struct kobject *kobj,
	51	struct attribute attr, char buf)
	52	{
	53	struct blk_ia_range_sysfs_entry *entry =
	54	container_of(attr, struct blk_ia_range_sysfs_entry, attr);
	55	struct blk_independent_access_range *iar =
	56	container_of(kobj, struct blk_independent_access_range, kobj);
a2247f19	57
41e46b3c	58	return entry->show(iar, buf);
a2247f19 DLM	59	}
	60
	61	static const struct sysfs_ops blk_ia_range_sysfs_ops = {
	62	.show = blk_ia_range_sysfs_show,
	63	};
	64
	65	/*
	66	* Independent access range entries are not freed individually, but alltogether
	67	* with struct blk_independent_access_ranges and its array of ranges. Since
	68	* kobject_add() takes a reference on the parent kobject contained in
	69	* struct blk_independent_access_ranges, the array of independent access range
	70	* entries cannot be freed until kobject_del() is called for all entries.
	71	* So we do not need to do anything here, but still need this no-op release
	72	* operation to avoid complaints from the kobject code.
	73	*/
	74	static void blk_ia_range_sysfs_nop_release(struct kobject *kobj)
	75	{
	76	}
	77
5f622417	78	static const struct kobj_type blk_ia_range_ktype = {
a2247f19 DLM	79	.sysfs_ops = &blk_ia_range_sysfs_ops,
	80	.default_groups = blk_ia_range_groups,
	81	.release = blk_ia_range_sysfs_nop_release,
	82	};
	83
	84	/*
	85	* This will be executed only after all independent access range entries are
	86	* removed with kobject_del(), at which point, it is safe to free everything,
	87	* including the array of ranges.
	88	*/
	89	static void blk_ia_ranges_sysfs_release(struct kobject *kobj)
	90	{
	91	struct blk_independent_access_ranges *iars =
	92	container_of(kobj, struct blk_independent_access_ranges, kobj);
	93
	94	kfree(iars);
	95	}
	96
5f622417	97	static const struct kobj_type blk_ia_ranges_ktype = {
a2247f19 DLM	98	.release = blk_ia_ranges_sysfs_release,
	99	};
	100
	101	/**
438cd742 JA	102	* disk_register_independent_access_ranges - register with sysfs a set of
438cd742 JA	103	* independent access ranges
a2247f19	104	* @disk: Target disk
a2247f19 DLM	105	*
a2247f19 DLM	106	* Register with sysfs a set of independent access ranges for @disk.
a2247f19	107	*/
22d0c408	108	int disk_register_independent_access_ranges(struct gendisk *disk)
a2247f19	109	{
22d0c408	110	struct blk_independent_access_ranges *iars = disk->ia_ranges;
a2247f19	111	struct request_queue *q = disk->queue;
a2247f19 DLM	112	int i, ret;
	113
	114	lockdep_assert_held(&q->sysfs_dir_lock);
	115	lockdep_assert_held(&q->sysfs_lock);
	116
a2247f19 DLM	117	if (!iars)
	118	return 0;
	119
	120	/*
	121	* At this point, iars is the new set of sector access ranges that needs
	122	* to be registered with sysfs.
	123	*/
	124	WARN_ON(iars->sysfs_registered);
	125	ret = kobject_init_and_add(&iars->kobj, &blk_ia_ranges_ktype,
2bd85221 CH	126	&disk->queue_kobj, "%s",
2bd85221 CH	127	"independent_access_ranges");
a2247f19	128	if (ret) {
6a27d28c	129	disk->ia_ranges = NULL;
83114df3	130	kobject_put(&iars->kobj);
a2247f19 DLM	131	return ret;
	132	}
	133
	134	for (i = 0; i < iars->nr_ia_ranges; i++) {
a2247f19 DLM	135	ret = kobject_init_and_add(&iars->ia_range[i].kobj,
	136	&blk_ia_range_ktype, &iars->kobj,
	137	"%d", i);
	138	if (ret) {
	139	while (--i >= 0)
	140	kobject_del(&iars->ia_range[i].kobj);
	141	kobject_del(&iars->kobj);
	142	kobject_put(&iars->kobj);
	143	return ret;
	144	}
	145	}
	146
	147	iars->sysfs_registered = true;
	148
	149	return 0;
	150	}
	151
	152	void disk_unregister_independent_access_ranges(struct gendisk *disk)
	153	{
	154	struct request_queue *q = disk->queue;
6a27d28c	155	struct blk_independent_access_ranges *iars = disk->ia_ranges;
a2247f19 DLM	156	int i;
	157
	158	lockdep_assert_held(&q->sysfs_dir_lock);
	159	lockdep_assert_held(&q->sysfs_lock);
	160
	161	if (!iars)
	162	return;
	163
	164	if (iars->sysfs_registered) {
	165	for (i = 0; i < iars->nr_ia_ranges; i++)
	166	kobject_del(&iars->ia_range[i].kobj);
	167	kobject_del(&iars->kobj);
	168	kobject_put(&iars->kobj);
	169	} else {
	170	kfree(iars);
	171	}
	172
6a27d28c	173	disk->ia_ranges = NULL;
a2247f19 DLM	174	}
	175
	176	static struct blk_independent_access_range *
	177	disk_find_ia_range(struct blk_independent_access_ranges *iars,
	178	sector_t sector)
	179	{
	180	struct blk_independent_access_range *iar;
	181	int i;
	182
	183	for (i = 0; i < iars->nr_ia_ranges; i++) {
	184	iar = &iars->ia_range[i];
	185	if (sector >= iar->sector &&
	186	sector < iar->sector + iar->nr_sectors)
	187	return iar;
	188	}
	189
	190	return NULL;
	191	}
	192
	193	static bool disk_check_ia_ranges(struct gendisk *disk,
	194	struct blk_independent_access_ranges *iars)
	195	{
	196	struct blk_independent_access_range iar, tmp;
	197	sector_t capacity = get_capacity(disk);
	198	sector_t sector = 0;
	199	int i;
	200
22d0c408 CH	201	if (WARN_ON_ONCE(!iars->nr_ia_ranges))
	202	return false;
	203
a2247f19 DLM	204	/*
	205	* While sorting the ranges in increasing LBA order, check that the
	206	* ranges do not overlap, that there are no sector holes and that all
	207	* sectors belong to one range.
	208	*/
	209	for (i = 0; i < iars->nr_ia_ranges; i++) {
	210	tmp = disk_find_ia_range(iars, sector);
	211	if (!tmp \|\| tmp->sector != sector) {
	212	pr_warn("Invalid non-contiguous independent access ranges\n");
	213	return false;
	214	}
	215
	216	iar = &iars->ia_range[i];
	217	if (tmp != iar) {
	218	swap(iar->sector, tmp->sector);
	219	swap(iar->nr_sectors, tmp->nr_sectors);
	220	}
	221
	222	sector += iar->nr_sectors;
	223	}
	224
	225	if (sector != capacity) {
	226	pr_warn("Independent access ranges do not match disk capacity\n");
	227	return false;
	228	}
	229
	230	return true;
	231	}
	232
	233	static bool disk_ia_ranges_changed(struct gendisk *disk,
	234	struct blk_independent_access_ranges *new)
	235	{
6a27d28c	236	struct blk_independent_access_ranges *old = disk->ia_ranges;
a2247f19 DLM	237	int i;
	238
	239	if (!old)
	240	return true;
	241
	242	if (old->nr_ia_ranges != new->nr_ia_ranges)
	243	return true;
	244
	245	for (i = 0; i < old->nr_ia_ranges; i++) {
	246	if (new->ia_range[i].sector != old->ia_range[i].sector \|\|
	247	new->ia_range[i].nr_sectors != old->ia_range[i].nr_sectors)
	248	return true;
	249	}
	250
	251	return false;
	252	}
	253
	254	/**
	255	* disk_alloc_independent_access_ranges - Allocate an independent access ranges
	256	* data structure
	257	* @disk: target disk
	258	* @nr_ia_ranges: Number of independent access ranges
	259	*
	260	* Allocate a struct blk_independent_access_ranges structure with @nr_ia_ranges
	261	* access range descriptors.
	262	*/
	263	struct blk_independent_access_ranges *
	264	disk_alloc_independent_access_ranges(struct gendisk *disk, int nr_ia_ranges)
	265	{
	266	struct blk_independent_access_ranges *iars;
	267
	268	iars = kzalloc_node(struct_size(iars, ia_range, nr_ia_ranges),
	269	GFP_KERNEL, disk->queue->node);
	270	if (iars)
	271	iars->nr_ia_ranges = nr_ia_ranges;
	272	return iars;
	273	}
	274	EXPORT_SYMBOL_GPL(disk_alloc_independent_access_ranges);
	275
	276	/**
	277	* disk_set_independent_access_ranges - Set a disk independent access ranges
	278	* @disk: target disk
	279	* @iars: independent access ranges structure
	280	*
	281	* Set the independent access ranges information of the request queue
	282	* of @disk to @iars. If @iars is NULL and the independent access ranges
	283	* structure already set is cleared. If there are no differences between
	284	* @iars and the independent access ranges structure already set, @iars
	285	* is freed.
	286	*/
	287	void disk_set_independent_access_ranges(struct gendisk *disk,
	288	struct blk_independent_access_ranges *iars)
	289	{
	290	struct request_queue *q = disk->queue;
	291
22d0c408 CH	292	mutex_lock(&q->sysfs_dir_lock);
	293	mutex_lock(&q->sysfs_lock);
	294	if (iars && !disk_check_ia_ranges(disk, iars)) {
a2247f19 DLM	295	kfree(iars);
	296	iars = NULL;
	297	}
22d0c408 CH	298	if (iars && !disk_ia_ranges_changed(disk, iars)) {
	299	kfree(iars);
	300	goto unlock;
a2247f19 DLM	301	}
	302
	303	/*
	304	* This may be called for a registered queue. E.g. during a device
	305	* revalidation. If that is the case, we need to unregister the old
	306	* set of independent access ranges and register the new set. If the
	307	* queue is not registered, registration of the device request queue
22d0c408	308	* will register the independent access ranges.
a2247f19	309	*/
22d0c408 CH	310	disk_unregister_independent_access_ranges(disk);
	311	disk->ia_ranges = iars;
	312	if (blk_queue_registered(q))
	313	disk_register_independent_access_ranges(disk);
a2247f19 DLM	314	unlock:
	315	mutex_unlock(&q->sysfs_lock);
	316	mutex_unlock(&q->sysfs_dir_lock);
	317	}
	318	EXPORT_SYMBOL_GPL(disk_set_independent_access_ranges);