diff options
Diffstat (limited to 'block/blk-ia-ranges.c')
| -rw-r--r-- | block/blk-ia-ranges.c | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/block/blk-ia-ranges.c b/block/blk-ia-ranges.c new file mode 100644 index 000000000000..c246c425d0d7 --- /dev/null +++ b/block/blk-ia-ranges.c @@ -0,0 +1,348 @@ +// 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); |