| /* |
| * bio-integrity.c - bio data integrity extensions |
| * |
| * Copyright (C) 2007, 2008, 2009 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/export.h> |
| #include <linux/bio.h> |
| #include <linux/workqueue.h> |
| #include <linux/slab.h> |
| #include "blk.h" |
| |
| #define BIP_INLINE_VECS 4 |
| |
| static struct kmem_cache *bip_slab; |
| static struct workqueue_struct *kintegrityd_wq; |
| |
| void blk_flush_integrity(void) |
| { |
| flush_workqueue(kintegrityd_wq); |
| } |
| |
| /** |
| * bio_integrity_alloc - Allocate integrity payload and attach it to bio |
| * @bio: bio to attach integrity metadata to |
| * @gfp_mask: Memory allocation mask |
| * @nr_vecs: Number of integrity metadata scatter-gather elements |
| * |
| * Description: This function prepares a bio for attaching integrity |
| * metadata. nr_vecs specifies the maximum number of pages containing |
| * integrity metadata that can be attached. |
| */ |
| struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, |
| gfp_t gfp_mask, |
| unsigned int nr_vecs) |
| { |
| struct bio_integrity_payload *bip; |
| struct bio_set *bs = bio->bi_pool; |
| unsigned inline_vecs; |
| |
| if (!bs || !bs->bio_integrity_pool) { |
| bip = kmalloc(sizeof(struct bio_integrity_payload) + |
| sizeof(struct bio_vec) * nr_vecs, gfp_mask); |
| inline_vecs = nr_vecs; |
| } else { |
| bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask); |
| inline_vecs = BIP_INLINE_VECS; |
| } |
| |
| if (unlikely(!bip)) |
| return ERR_PTR(-ENOMEM); |
| |
| memset(bip, 0, sizeof(*bip)); |
| |
| if (nr_vecs > inline_vecs) { |
| unsigned long idx = 0; |
| |
| bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx, |
| bs->bvec_integrity_pool); |
| if (!bip->bip_vec) |
| goto err; |
| bip->bip_max_vcnt = bvec_nr_vecs(idx); |
| bip->bip_slab = idx; |
| } else { |
| bip->bip_vec = bip->bip_inline_vecs; |
| bip->bip_max_vcnt = inline_vecs; |
| } |
| |
| bip->bip_bio = bio; |
| bio->bi_integrity = bip; |
| bio->bi_opf |= REQ_INTEGRITY; |
| |
| return bip; |
| err: |
| mempool_free(bip, bs->bio_integrity_pool); |
| return ERR_PTR(-ENOMEM); |
| } |
| EXPORT_SYMBOL(bio_integrity_alloc); |
| |
| /** |
| * bio_integrity_free - Free bio integrity payload |
| * @bio: bio containing bip to be freed |
| * |
| * Description: Used to free the integrity portion of a bio. Usually |
| * called from bio_free(). |
| */ |
| static void bio_integrity_free(struct bio *bio) |
| { |
| struct bio_integrity_payload *bip = bio_integrity(bio); |
| struct bio_set *bs = bio->bi_pool; |
| |
| if (bip->bip_flags & BIP_BLOCK_INTEGRITY) |
| kfree(page_address(bip->bip_vec->bv_page) + |
| bip->bip_vec->bv_offset); |
| |
| if (bs && bs->bio_integrity_pool) { |
| bvec_free(bs->bvec_integrity_pool, bip->bip_vec, bip->bip_slab); |
| |
| mempool_free(bip, bs->bio_integrity_pool); |
| } else { |
| kfree(bip); |
| } |
| |
| bio->bi_integrity = NULL; |
| bio->bi_opf &= ~REQ_INTEGRITY; |
| } |
| |
| /** |
| * bio_integrity_add_page - Attach integrity metadata |
| * @bio: bio to update |
| * @page: page containing integrity metadata |
| * @len: number of bytes of integrity metadata in page |
| * @offset: start offset within page |
| * |
| * Description: Attach a page containing integrity metadata to bio. |
| */ |
| int bio_integrity_add_page(struct bio *bio, struct page *page, |
| unsigned int len, unsigned int offset) |
| { |
| struct bio_integrity_payload *bip = bio_integrity(bio); |
| struct bio_vec *iv; |
| |
| if (bip->bip_vcnt >= bip->bip_max_vcnt) { |
| printk(KERN_ERR "%s: bip_vec full\n", __func__); |
| return 0; |
| } |
| |
| iv = bip->bip_vec + bip->bip_vcnt; |
| |
| if (bip->bip_vcnt && |
| bvec_gap_to_prev(bio->bi_disk->queue, |
| &bip->bip_vec[bip->bip_vcnt - 1], offset)) |
| return 0; |
| |
| iv->bv_page = page; |
| iv->bv_len = len; |
| iv->bv_offset = offset; |
| bip->bip_vcnt++; |
| |
| return len; |
| } |
| EXPORT_SYMBOL(bio_integrity_add_page); |
| |
| /** |
| * bio_integrity_intervals - Return number of integrity intervals for a bio |
| * @bi: blk_integrity profile for device |
| * @sectors: Size of the bio in 512-byte sectors |
| * |
| * Description: The block layer calculates everything in 512 byte |
| * sectors but integrity metadata is done in terms of the data integrity |
| * interval size of the storage device. Convert the block layer sectors |
| * to the appropriate number of integrity intervals. |
| */ |
| static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi, |
| unsigned int sectors) |
| { |
| return sectors >> (bi->interval_exp - 9); |
| } |
| |
| static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi, |
| unsigned int sectors) |
| { |
| return bio_integrity_intervals(bi, sectors) * bi->tuple_size; |
| } |
| |
| /** |
| * bio_integrity_process - Process integrity metadata for a bio |
| * @bio: bio to generate/verify integrity metadata for |
| * @proc_iter: iterator to process |
| * @proc_fn: Pointer to the relevant processing function |
| */ |
| static blk_status_t bio_integrity_process(struct bio *bio, |
| struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn) |
| { |
| struct blk_integrity *bi = blk_get_integrity(bio->bi_disk); |
| struct blk_integrity_iter iter; |
| struct bvec_iter bviter; |
| struct bio_vec bv; |
| struct bio_integrity_payload *bip = bio_integrity(bio); |
| blk_status_t ret = BLK_STS_OK; |
| void *prot_buf = page_address(bip->bip_vec->bv_page) + |
| bip->bip_vec->bv_offset; |
| |
| iter.disk_name = bio->bi_disk->disk_name; |
| iter.interval = 1 << bi->interval_exp; |
| iter.seed = proc_iter->bi_sector; |
| iter.prot_buf = prot_buf; |
| |
| __bio_for_each_segment(bv, bio, bviter, *proc_iter) { |
| void *kaddr = kmap_atomic(bv.bv_page); |
| |
| iter.data_buf = kaddr + bv.bv_offset; |
| iter.data_size = bv.bv_len; |
| |
| ret = proc_fn(&iter); |
| if (ret) { |
| kunmap_atomic(kaddr); |
| return ret; |
| } |
| |
| kunmap_atomic(kaddr); |
| } |
| return ret; |
| } |
| |
| /** |
| * bio_integrity_prep - Prepare bio for integrity I/O |
| * @bio: bio to prepare |
| * |
| * Description: Checks if the bio already has an integrity payload attached. |
| * If it does, the payload has been generated by another kernel subsystem, |
| * and we just pass it through. Otherwise allocates integrity payload. |
| * The bio must have data direction, target device and start sector set priot |
| * to calling. In the WRITE case, integrity metadata will be generated using |
| * the block device's integrity function. In the READ case, the buffer |
| * will be prepared for DMA and a suitable end_io handler set up. |
| */ |
| bool bio_integrity_prep(struct bio *bio) |
| { |
| struct bio_integrity_payload *bip; |
| struct blk_integrity *bi = blk_get_integrity(bio->bi_disk); |
| struct request_queue *q = bio->bi_disk->queue; |
| void *buf; |
| unsigned long start, end; |
| unsigned int len, nr_pages; |
| unsigned int bytes, offset, i; |
| unsigned int intervals; |
| blk_status_t status; |
| |
| if (!bi) |
| return true; |
| |
| if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE) |
| return true; |
| |
| if (!bio_sectors(bio)) |
| return true; |
| |
| /* Already protected? */ |
| if (bio_integrity(bio)) |
| return true; |
| |
| if (bio_data_dir(bio) == READ) { |
| if (!bi->profile->verify_fn || |
| !(bi->flags & BLK_INTEGRITY_VERIFY)) |
| return true; |
| } else { |
| if (!bi->profile->generate_fn || |
| !(bi->flags & BLK_INTEGRITY_GENERATE)) |
| return true; |
| } |
| intervals = bio_integrity_intervals(bi, bio_sectors(bio)); |
| |
| /* Allocate kernel buffer for protection data */ |
| len = intervals * bi->tuple_size; |
| buf = kmalloc(len, GFP_NOIO | q->bounce_gfp); |
| status = BLK_STS_RESOURCE; |
| if (unlikely(buf == NULL)) { |
| printk(KERN_ERR "could not allocate integrity buffer\n"); |
| goto err_end_io; |
| } |
| |
| end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| start = ((unsigned long) buf) >> PAGE_SHIFT; |
| nr_pages = end - start; |
| |
| /* Allocate bio integrity payload and integrity vectors */ |
| bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages); |
| if (IS_ERR(bip)) { |
| printk(KERN_ERR "could not allocate data integrity bioset\n"); |
| kfree(buf); |
| status = BLK_STS_RESOURCE; |
| goto err_end_io; |
| } |
| |
| bip->bip_flags |= BIP_BLOCK_INTEGRITY; |
| bip->bip_iter.bi_size = len; |
| bip_set_seed(bip, bio->bi_iter.bi_sector); |
| |
| if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM) |
| bip->bip_flags |= BIP_IP_CHECKSUM; |
| |
| /* Map it */ |
| offset = offset_in_page(buf); |
| for (i = 0 ; i < nr_pages ; i++) { |
| int ret; |
| bytes = PAGE_SIZE - offset; |
| |
| if (len <= 0) |
| break; |
| |
| if (bytes > len) |
| bytes = len; |
| |
| ret = bio_integrity_add_page(bio, virt_to_page(buf), |
| bytes, offset); |
| |
| if (ret == 0) |
| return false; |
| |
| if (ret < bytes) |
| break; |
| |
| buf += bytes; |
| len -= bytes; |
| offset = 0; |
| } |
| |
| /* Auto-generate integrity metadata if this is a write */ |
| if (bio_data_dir(bio) == WRITE) { |
| bio_integrity_process(bio, &bio->bi_iter, |
| bi->profile->generate_fn); |
| } |
| return true; |
| |
| err_end_io: |
| bio->bi_status = status; |
| bio_endio(bio); |
| return false; |
| |
| } |
| EXPORT_SYMBOL(bio_integrity_prep); |
| |
| /** |
| * bio_integrity_verify_fn - Integrity I/O completion worker |
| * @work: Work struct stored in bio to be verified |
| * |
| * Description: This workqueue function is called to complete a READ |
| * request. The function verifies the transferred integrity metadata |
| * and then calls the original bio end_io function. |
| */ |
| static void bio_integrity_verify_fn(struct work_struct *work) |
| { |
| struct bio_integrity_payload *bip = |
| container_of(work, struct bio_integrity_payload, bip_work); |
| struct bio *bio = bip->bip_bio; |
| struct blk_integrity *bi = blk_get_integrity(bio->bi_disk); |
| struct bvec_iter iter = bio->bi_iter; |
| |
| /* |
| * At the moment verify is called bio's iterator was advanced |
| * during split and completion, we need to rewind iterator to |
| * it's original position. |
| */ |
| if (bio_rewind_iter(bio, &iter, iter.bi_done)) { |
| bio->bi_status = bio_integrity_process(bio, &iter, |
| bi->profile->verify_fn); |
| } else { |
| bio->bi_status = BLK_STS_IOERR; |
| } |
| |
| bio_integrity_free(bio); |
| bio_endio(bio); |
| } |
| |
| /** |
| * __bio_integrity_endio - Integrity I/O completion function |
| * @bio: Protected bio |
| * @error: Pointer to errno |
| * |
| * Description: Completion for integrity I/O |
| * |
| * Normally I/O completion is done in interrupt context. However, |
| * verifying I/O integrity is a time-consuming task which must be run |
| * in process context. This function postpones completion |
| * accordingly. |
| */ |
| bool __bio_integrity_endio(struct bio *bio) |
| { |
| if (bio_op(bio) == REQ_OP_READ && !bio->bi_status) { |
| struct bio_integrity_payload *bip = bio_integrity(bio); |
| |
| INIT_WORK(&bip->bip_work, bio_integrity_verify_fn); |
| queue_work(kintegrityd_wq, &bip->bip_work); |
| return false; |
| } |
| |
| bio_integrity_free(bio); |
| return true; |
| } |
| |
| /** |
| * bio_integrity_advance - Advance integrity vector |
| * @bio: bio whose integrity vector to update |
| * @bytes_done: number of data bytes that have been completed |
| * |
| * Description: This function calculates how many integrity bytes the |
| * number of completed data bytes correspond to and advances the |
| * integrity vector accordingly. |
| */ |
| void bio_integrity_advance(struct bio *bio, unsigned int bytes_done) |
| { |
| struct bio_integrity_payload *bip = bio_integrity(bio); |
| struct blk_integrity *bi = blk_get_integrity(bio->bi_disk); |
| unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9); |
| |
| bip->bip_iter.bi_sector += bytes_done >> 9; |
| bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes); |
| } |
| EXPORT_SYMBOL(bio_integrity_advance); |
| |
| /** |
| * bio_integrity_trim - Trim integrity vector |
| * @bio: bio whose integrity vector to update |
| * |
| * Description: Used to trim the integrity vector in a cloned bio. |
| */ |
| void bio_integrity_trim(struct bio *bio) |
| { |
| struct bio_integrity_payload *bip = bio_integrity(bio); |
| struct blk_integrity *bi = blk_get_integrity(bio->bi_disk); |
| |
| bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio)); |
| } |
| EXPORT_SYMBOL(bio_integrity_trim); |
| |
| /** |
| * bio_integrity_clone - Callback for cloning bios with integrity metadata |
| * @bio: New bio |
| * @bio_src: Original bio |
| * @gfp_mask: Memory allocation mask |
| * |
| * Description: Called to allocate a bip when cloning a bio |
| */ |
| int bio_integrity_clone(struct bio *bio, struct bio *bio_src, |
| gfp_t gfp_mask) |
| { |
| struct bio_integrity_payload *bip_src = bio_integrity(bio_src); |
| struct bio_integrity_payload *bip; |
| |
| BUG_ON(bip_src == NULL); |
| |
| bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt); |
| if (IS_ERR(bip)) |
| return PTR_ERR(bip); |
| |
| memcpy(bip->bip_vec, bip_src->bip_vec, |
| bip_src->bip_vcnt * sizeof(struct bio_vec)); |
| |
| bip->bip_vcnt = bip_src->bip_vcnt; |
| bip->bip_iter = bip_src->bip_iter; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(bio_integrity_clone); |
| |
| int bioset_integrity_create(struct bio_set *bs, int pool_size) |
| { |
| if (bs->bio_integrity_pool) |
| return 0; |
| |
| bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab); |
| if (!bs->bio_integrity_pool) |
| return -1; |
| |
| bs->bvec_integrity_pool = biovec_create_pool(pool_size); |
| if (!bs->bvec_integrity_pool) { |
| mempool_destroy(bs->bio_integrity_pool); |
| return -1; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(bioset_integrity_create); |
| |
| void bioset_integrity_free(struct bio_set *bs) |
| { |
| if (bs->bio_integrity_pool) |
| mempool_destroy(bs->bio_integrity_pool); |
| |
| if (bs->bvec_integrity_pool) |
| mempool_destroy(bs->bvec_integrity_pool); |
| } |
| EXPORT_SYMBOL(bioset_integrity_free); |
| |
| void __init bio_integrity_init(void) |
| { |
| /* |
| * kintegrityd won't block much but may burn a lot of CPU cycles. |
| * Make it highpri CPU intensive wq with max concurrency of 1. |
| */ |
| kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM | |
| WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1); |
| if (!kintegrityd_wq) |
| panic("Failed to create kintegrityd\n"); |
| |
| bip_slab = kmem_cache_create("bio_integrity_payload", |
| sizeof(struct bio_integrity_payload) + |
| sizeof(struct bio_vec) * BIP_INLINE_VECS, |
| 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
| } |