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