/* * 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/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" 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);