diff options
Diffstat (limited to 'kernel/block/blk-integrity.c')
| -rw-r--r-- | kernel/block/blk-integrity.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/kernel/block/blk-integrity.c b/kernel/block/blk-integrity.c new file mode 100644 index 000000000..79ffb4855 --- /dev/null +++ b/kernel/block/blk-integrity.c @@ -0,0 +1,483 @@ +/* + * blk-integrity.c - Block layer data integrity extensions + * + * Copyright (C) 2007, 2008 Oracle Corporation + * Written by: Martin K. Petersen <martin.petersen@oracle.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, + * USA. + * + */ + +#include <linux/blkdev.h> +#include <linux/mempool.h> +#include <linux/bio.h> +#include <linux/scatterlist.h> +#include <linux/export.h> +#include <linux/slab.h> + +#include "blk.h" + +static struct kmem_cache *integrity_cachep; + +static const char *bi_unsupported_name = "unsupported"; + +/** + * 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(&ivprv, &iv)) + goto new_segment; + + if (!BIOVEC_SEG_BOUNDARY(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(&ivprv, &iv)) + goto new_segment; + + if (!BIOVEC_SEG_BOUNDARY(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->integrity; + struct blk_integrity *b2 = gd2->integrity; + + if (!b1 && !b2) + return 0; + + if (!b1 || !b2) + return -1; + + if (b1->interval != b2->interval) { + pr_err("%s: %s/%s protection interval %u != %u\n", + __func__, gd1->disk_name, gd2->disk_name, + b1->interval, b2->interval); + return -1; + } + + if (b1->tuple_size != b2->tuple_size) { + printk(KERN_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)) { + printk(KERN_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 (strcmp(b1->name, b2->name)) { + printk(KERN_ERR "%s: %s/%s type %s != %s\n", __func__, + gd1->disk_name, gd2->disk_name, + b1->name, b2->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; + + 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 blk_integrity *bi = + container_of(kobj, struct blk_integrity, kobj); + 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 blk_integrity *bi = + container_of(kobj, struct blk_integrity, kobj); + 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 != NULL && bi->name != NULL) + return sprintf(page, "%s\n", bi->name); + else + return sprintf(page, "none\n"); +} + +static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page) +{ + if (bi != NULL) + return sprintf(page, "%u\n", bi->tag_size); + else + return sprintf(page, "0\n"); +} + +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 = S_IRUGO }, + .show = integrity_format_show, +}; + +static struct integrity_sysfs_entry integrity_tag_size_entry = { + .attr = { .name = "tag_size", .mode = S_IRUGO }, + .show = integrity_tag_size_show, +}; + +static struct integrity_sysfs_entry integrity_verify_entry = { + .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR }, + .show = integrity_verify_show, + .store = integrity_verify_store, +}; + +static struct integrity_sysfs_entry integrity_generate_entry = { + .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR }, + .show = integrity_generate_show, + .store = integrity_generate_store, +}; + +static struct integrity_sysfs_entry integrity_device_entry = { + .attr = { .name = "device_is_integrity_capable", .mode = S_IRUGO }, + .show = integrity_device_show, +}; + +static struct attribute *integrity_attrs[] = { + &integrity_format_entry.attr, + &integrity_tag_size_entry.attr, + &integrity_verify_entry.attr, + &integrity_generate_entry.attr, + &integrity_device_entry.attr, + NULL, +}; + +static const struct sysfs_ops integrity_ops = { + .show = &integrity_attr_show, + .store = &integrity_attr_store, +}; + +static int __init blk_dev_integrity_init(void) +{ + integrity_cachep = kmem_cache_create("blkdev_integrity", + sizeof(struct blk_integrity), + 0, SLAB_PANIC, NULL); + return 0; +} +subsys_initcall(blk_dev_integrity_init); + +static void blk_integrity_release(struct kobject *kobj) +{ + struct blk_integrity *bi = + container_of(kobj, struct blk_integrity, kobj); + + kmem_cache_free(integrity_cachep, bi); +} + +static struct kobj_type integrity_ktype = { + .default_attrs = integrity_attrs, + .sysfs_ops = &integrity_ops, + .release = blk_integrity_release, +}; + +bool blk_integrity_is_initialized(struct gendisk *disk) +{ + struct blk_integrity *bi = blk_get_integrity(disk); + + return (bi && bi->name && strcmp(bi->name, bi_unsupported_name) != 0); +} +EXPORT_SYMBOL(blk_integrity_is_initialized); + +/** + * blk_integrity_register - Register a gendisk as being integrity-capable + * @disk: struct gendisk pointer to make integrity-aware + * @template: optional 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. If template is NULL the new profile is allocated but + * not filled out. See Documentation/block/data-integrity.txt. + */ +int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) +{ + struct blk_integrity *bi; + + BUG_ON(disk == NULL); + + if (disk->integrity == NULL) { + bi = kmem_cache_alloc(integrity_cachep, + GFP_KERNEL | __GFP_ZERO); + if (!bi) + return -1; + + if (kobject_init_and_add(&bi->kobj, &integrity_ktype, + &disk_to_dev(disk)->kobj, + "%s", "integrity")) { + kmem_cache_free(integrity_cachep, bi); + return -1; + } + + kobject_uevent(&bi->kobj, KOBJ_ADD); + + bi->flags |= BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE; + bi->interval = queue_logical_block_size(disk->queue); + disk->integrity = bi; + } else + bi = disk->integrity; + + /* Use the provided profile as template */ + if (template != NULL) { + bi->name = template->name; + bi->generate_fn = template->generate_fn; + bi->verify_fn = template->verify_fn; + bi->tuple_size = template->tuple_size; + bi->tag_size = template->tag_size; + bi->flags |= template->flags; + } else + bi->name = bi_unsupported_name; + + disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES; + + return 0; +} +EXPORT_SYMBOL(blk_integrity_register); + +/** + * blk_integrity_unregister - Remove block integrity profile + * @disk: disk whose integrity profile to deallocate + * + * Description: This function frees all memory used by the block + * integrity profile. To be called at device teardown. + */ +void blk_integrity_unregister(struct gendisk *disk) +{ + struct blk_integrity *bi; + + if (!disk || !disk->integrity) + return; + + disk->queue->backing_dev_info.capabilities &= ~BDI_CAP_STABLE_WRITES; + + bi = disk->integrity; + + kobject_uevent(&bi->kobj, KOBJ_REMOVE); + kobject_del(&bi->kobj); + kobject_put(&bi->kobj); + disk->integrity = NULL; +} +EXPORT_SYMBOL(blk_integrity_unregister); |