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// SPDX-License-Identifier: GPL-2.0
/*
* blk-integrity.c - Block layer data integrity extensions
*
* Copyright (C) 2007, 2008 Oracle Corporation
* Written by: Martin K. Petersen <martin.petersen@oracle.com>
*/
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/mempool.h>
#include <linux/bio.h>
#include <linux/scatterlist.h>
#include <linux/export.h>
#include <linux/slab.h>
#include "blk.h"
/**
* blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
* @q: request queue
* @bio: bio with integrity metadata attached
*
* Description: Returns the number of elements required in a
* scatterlist corresponding to the integrity metadata in a bio.
*/
int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
{
struct bio_vec iv, ivprv = { NULL };
unsigned int segments = 0;
unsigned int seg_size = 0;
struct bvec_iter iter;
int prev = 0;
bio_for_each_integrity_vec(iv, bio, iter) {
if (prev) {
if (!biovec_phys_mergeable(q, &ivprv, &iv))
goto new_segment;
if (seg_size + iv.bv_len > queue_max_segment_size(q))
goto new_segment;
seg_size += iv.bv_len;
} else {
new_segment:
segments++;
seg_size = iv.bv_len;
}
prev = 1;
ivprv = iv;
}
return segments;
}
EXPORT_SYMBOL(blk_rq_count_integrity_sg);
/**
* blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
* @q: request queue
* @bio: bio with integrity metadata attached
* @sglist: target scatterlist
*
* Description: Map the integrity vectors in request into a
* scatterlist. The scatterlist must be big enough to hold all
* elements. I.e. sized using blk_rq_count_integrity_sg().
*/
int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
struct scatterlist *sglist)
{
struct bio_vec iv, ivprv = { NULL };
struct scatterlist *sg = NULL;
unsigned int segments = 0;
struct bvec_iter iter;
int prev = 0;
bio_for_each_integrity_vec(iv, bio, iter) {
if (prev) {
if (!biovec_phys_mergeable(q, &ivprv, &iv))
goto new_segment;
if (sg->length + iv.bv_len > queue_max_segment_size(q))
goto new_segment;
sg->length += iv.bv_len;
} else {
new_segment:
if (!sg)
sg = sglist;
else {
sg_unmark_end(sg);
sg = sg_next(sg);
}
sg_set_page(sg, iv.bv_page, iv.bv_len, iv.bv_offset);
segments++;
}
prev = 1;
ivprv = iv;
}
if (sg)
sg_mark_end(sg);
return segments;
}
EXPORT_SYMBOL(blk_rq_map_integrity_sg);
/**
* blk_integrity_compare - Compare integrity profile of two disks
* @gd1: Disk to compare
* @gd2: Disk to compare
*
* Description: Meta-devices like DM and MD need to verify that all
* sub-devices use the same integrity format before advertising to
* upper layers that they can send/receive integrity metadata. This
* function can be used to check whether two gendisk devices have
* compatible integrity formats.
*/
int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
{
struct blk_integrity *b1 = &gd1->queue->integrity;
struct blk_integrity *b2 = &gd2->queue->integrity;
if (!b1->profile && !b2->profile)
return 0;
if (!b1->profile || !b2->profile)
return -1;
if (b1->interval_exp != b2->interval_exp) {
pr_err("%s: %s/%s protection interval %u != %u\n",
__func__, gd1->disk_name, gd2->disk_name,
1 << b1->interval_exp, 1 << b2->interval_exp);
return -1;
}
if (b1->tuple_size != b2->tuple_size) {
pr_err("%s: %s/%s tuple sz %u != %u\n", __func__,
gd1->disk_name, gd2->disk_name,
b1->tuple_size, b2->tuple_size);
return -1;
}
if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) {
pr_err("%s: %s/%s tag sz %u != %u\n", __func__,
gd1->disk_name, gd2->disk_name,
b1->tag_size, b2->tag_size);
return -1;
}
if (b1->profile != b2->profile) {
pr_err("%s: %s/%s type %s != %s\n", __func__,
gd1->disk_name, gd2->disk_name,
b1->profile->name, b2->profile->name);
return -1;
}
return 0;
}
EXPORT_SYMBOL(blk_integrity_compare);
bool blk_integrity_merge_rq(struct request_queue *q, struct request *req,
struct request *next)
{
if (blk_integrity_rq(req) == 0 && blk_integrity_rq(next) == 0)
return true;
if (blk_integrity_rq(req) == 0 || blk_integrity_rq(next) == 0)
return false;
if (bio_integrity(req->bio)->bip_flags !=
bio_integrity(next->bio)->bip_flags)
return false;
if (req->nr_integrity_segments + next->nr_integrity_segments >
q->limits.max_integrity_segments)
return false;
if (integrity_req_gap_back_merge(req, next->bio))
return false;
return true;
}
EXPORT_SYMBOL(blk_integrity_merge_rq);
bool blk_integrity_merge_bio(struct request_queue *q, struct request *req,
struct bio *bio)
{
int nr_integrity_segs;
struct bio *next = bio->bi_next;
if (blk_integrity_rq(req) == 0 && bio_integrity(bio) == NULL)
return true;
if (blk_integrity_rq(req) == 0 || bio_integrity(bio) == NULL)
return false;
if (bio_integrity(req->bio)->bip_flags != bio_integrity(bio)->bip_flags)
return false;
bio->bi_next = NULL;
nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
bio->bi_next = next;
if (req->nr_integrity_segments + nr_integrity_segs >
q->limits.max_integrity_segments)
return false;
req->nr_integrity_segments += nr_integrity_segs;
return true;
}
EXPORT_SYMBOL(blk_integrity_merge_bio);
struct integrity_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct blk_integrity *, char *);
ssize_t (*store)(struct blk_integrity *, const char *, size_t);
};
static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
char *page)
{
struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
struct blk_integrity *bi = &disk->queue->integrity;
struct integrity_sysfs_entry *entry =
container_of(attr, struct integrity_sysfs_entry, attr);
return entry->show(bi, page);
}
static ssize_t integrity_attr_store(struct kobject *kobj,
struct attribute *attr, const char *page,
size_t count)
{
struct gendisk *disk = container_of(kobj, struct gendisk, integrity_kobj);
struct blk_integrity *bi = &disk->queue->integrity;
struct integrity_sysfs_entry *entry =
container_of(attr, struct integrity_sysfs_entry, attr);
ssize_t ret = 0;
if (entry->store)
ret = entry->store(bi, page, count);
return ret;
}
static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
{
if (bi->profile && bi->profile->name)
return sprintf(page, "%s\n", bi->profile->name);
else
return sprintf(page, "none\n");
}
static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
{
return sprintf(page, "%u\n", bi->tag_size);
}
static ssize_t integrity_interval_show(struct blk_integrity *bi, char *page)
{
return sprintf(page, "%u\n",
bi->interval_exp ? 1 << bi->interval_exp : 0);
}
static ssize_t integrity_verify_store(struct blk_integrity *bi,
const char *page, size_t count)
{
char *p = (char *) page;
unsigned long val = simple_strtoul(p, &p, 10);
if (val)
bi->flags |= BLK_INTEGRITY_VERIFY;
else
bi->flags &= ~BLK_INTEGRITY_VERIFY;
return count;
}
static ssize_t integrity_verify_show(struct blk_integrity *bi, char *page)
{
return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_VERIFY) != 0);
}
static ssize_t integrity_generate_store(struct blk_integrity *bi,
const char *page, size_t count)
{
char *p = (char *) page;
unsigned long val = simple_strtoul(p, &p, 10);
if (val)
bi->flags |= BLK_INTEGRITY_GENERATE;
else
bi->flags &= ~BLK_INTEGRITY_GENERATE;
return count;
}
static ssize_t integrity_generate_show(struct blk_integrity *bi, char *page)
{
return sprintf(page, "%d\n", (bi->flags & BLK_INTEGRITY_GENERATE) != 0);
}
static ssize_t integrity_device_show(struct blk_integrity *bi, char *page)
{
return sprintf(page, "%u\n",
(bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) != 0);
}
static struct integrity_sysfs_entry integrity_format_entry = {
.attr = { .name = "format", .mode = 0444 },
.show = integrity_format_show,
};
static struct integrity_sysfs_entry integrity_tag_size_entry = {
.attr = { .name = "tag_size", .mode = 0444 },
.show = integrity_tag_size_show,
};
static struct integrity_sysfs_entry integrity_interval_entry = {
.attr = { .name = "protection_interval_bytes", .mode = 0444 },
.show = integrity_interval_show,
};
static struct integrity_sysfs_entry integrity_verify_entry = {
.attr = { .name = "read_verify", .mode = 0644 },
.show = integrity_verify_show,
.store = integrity_verify_store,
};
static struct integrity_sysfs_entry integrity_generate_entry = {
.attr = { .name = "write_generate", .mode = 0644 },
.show = integrity_generate_show,
.store = integrity_generate_store,
};
static struct integrity_sysfs_entry integrity_device_entry = {
.attr = { .name = "device_is_integrity_capable", .mode = 0444 },
.show = integrity_device_show,
};
static struct attribute *integrity_attrs[] = {
&integrity_format_entry.attr,
&integrity_tag_size_entry.attr,
&integrity_interval_entry.attr,
&integrity_verify_entry.attr,
&integrity_generate_entry.attr,
&integrity_device_entry.attr,
NULL,
};
ATTRIBUTE_GROUPS(integrity);
static const struct sysfs_ops integrity_ops = {
.show = &integrity_attr_show,
.store = &integrity_attr_store,
};
static struct kobj_type integrity_ktype = {
.default_groups = integrity_groups,
.sysfs_ops = &integrity_ops,
};
static blk_status_t blk_integrity_nop_fn(struct blk_integrity_iter *iter)
{
return BLK_STS_OK;
}
static void blk_integrity_nop_prepare(struct request *rq)
{
}
static void blk_integrity_nop_complete(struct request *rq,
unsigned int nr_bytes)
{
}
static const struct blk_integrity_profile nop_profile = {
.name = "nop",
.generate_fn = blk_integrity_nop_fn,
.verify_fn = blk_integrity_nop_fn,
.prepare_fn = blk_integrity_nop_prepare,
.complete_fn = blk_integrity_nop_complete,
};
/**
* blk_integrity_register - Register a gendisk as being integrity-capable
* @disk: struct gendisk pointer to make integrity-aware
* @template: block integrity profile to register
*
* Description: When a device needs to advertise itself as being able to
* send/receive integrity metadata it must use this function to register
* the capability with the block layer. The template is a blk_integrity
* struct with values appropriate for the underlying hardware. See
* Documentation/block/data-integrity.rst.
*/
void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
{
struct blk_integrity *bi = &disk->queue->integrity;
bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
template->flags;
bi->interval_exp = template->interval_exp ? :
ilog2(queue_logical_block_size(disk->queue));
bi->profile = template->profile ? template->profile : &nop_profile;
bi->tuple_size = template->tuple_size;
bi->tag_size = template->tag_size;
disk->queue->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
}
EXPORT_SYMBOL(blk_integrity_register);
/**
* blk_integrity_unregister - Unregister block integrity profile
* @disk: disk whose integrity profile to unregister
*
* Description: This function unregisters the integrity capability from
* a block device.
*/
void blk_integrity_unregister(struct gendisk *disk)
{
disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
}
EXPORT_SYMBOL(blk_integrity_unregister);
void blk_integrity_add(struct gendisk *disk)
{
if (kobject_init_and_add(&disk->integrity_kobj, &integrity_ktype,
&disk_to_dev(disk)->kobj, "%s", "integrity"))
return;
kobject_uevent(&disk->integrity_kobj, KOBJ_ADD);
}
void blk_integrity_del(struct gendisk *disk)
{
kobject_uevent(&disk->integrity_kobj, KOBJ_REMOVE);
kobject_del(&disk->integrity_kobj);
kobject_put(&disk->integrity_kobj);
}