block/blk-ia-ranges.c - linux - Git at Google

 // 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 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 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,
 				   &q->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);
	// 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 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 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,
	&q->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);