--- /dev/null
+// 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);
+ ssize_t ret;
+
+ mutex_lock(&iar->queue->sysfs_lock);
+ ret = entry->show(iar, buf);
+ mutex_unlock(&iar->queue->sysfs_lock);
+
+ return ret;
+}
+
+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_ia_ranges - register with sysfs a set of independent
+ * access ranges
+ * @disk: Target disk
+ * @new_iars: New set of independent access ranges
+ *
+ * Register with sysfs a set of independent access ranges for @disk.
+ * If @new_iars is not NULL, this set of ranges is registered and the old set
+ * specified by q->ia_ranges is unregistered. Otherwise, q->ia_ranges is
+ * registered if it is not already.
+ */
+int disk_register_independent_access_ranges(struct gendisk *disk,
+ struct blk_independent_access_ranges *new_iars)
+{
+ struct request_queue *q = disk->queue;
+ struct blk_independent_access_ranges *iars;
+ int i, ret;
+
+ lockdep_assert_held(&q->sysfs_dir_lock);
+ lockdep_assert_held(&q->sysfs_lock);
+
+ /* If a new range set is specified, unregister the old one */
+ if (new_iars) {
+ if (q->ia_ranges)
+ disk_unregister_independent_access_ranges(disk);
+ q->ia_ranges = new_iars;
+ }
+
+ iars = q->ia_ranges;
+ 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) {
+ q->ia_ranges = NULL;
+ kfree(iars);
+ return ret;
+ }
+
+ for (i = 0; i < iars->nr_ia_ranges; i++) {
+ iars->ia_range[i].queue = q;
+ 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 = q->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);
+ }
+
+ q->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;
+
+ /*
+ * 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->queue->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;
+
+ if (WARN_ON_ONCE(iars && !iars->nr_ia_ranges)) {
+ kfree(iars);
+ iars = NULL;
+ }
+
+ mutex_lock(&q->sysfs_dir_lock);
+ mutex_lock(&q->sysfs_lock);
+
+ if (iars) {
+ if (!disk_check_ia_ranges(disk, iars)) {
+ kfree(iars);
+ iars = NULL;
+ goto reg;
+ }
+
+ if (!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, so only swap in the
+ * new set and free the old one.
+ */
+reg:
+ if (blk_queue_registered(q)) {
+ disk_register_independent_access_ranges(disk, iars);
+ } else {
+ swap(q->ia_ranges, iars);
+ kfree(iars);
+ }
+
+unlock:
+ mutex_unlock(&q->sysfs_lock);
+ mutex_unlock(&q->sysfs_dir_lock);
+}
+EXPORT_SYMBOL_GPL(disk_set_independent_access_ranges);
projects / users / jedix / linux-maple.git / commitdiff