1 files changed, 492 insertions, 0 deletions

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
new file mode 100644
index 000000000..2e22a3f74
--- /dev/null
+++ b/block/bio-integrity.c
@@ -0,0 +1,492 @@
+/*
+ * 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);
+}
+
+void __bio_integrity_free(struct bio_set *bs, struct bio_integrity_payload *bip)
+{
+	if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
+		if (bip->bip_vec)
+			bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
+				  bip->bip_slab);
+		mempool_free(bip, &bs->bio_integrity_pool);
+	} else {
+		kfree(bip);
+	}
+}
+
+/**
+ * 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 || !mempool_initialized(&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:
+	__bio_integrity_free(bs, bip);
+	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);
+
+	__bio_integrity_free(bs, 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_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) {
+			printk(KERN_ERR "could not attach integrity payload\n");
+			status = BLK_STS_RESOURCE;
+			goto err_end_io;
+		}
+
+		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
+ *
+ * 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)
+{
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+
+	if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
+	    (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
+		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 += bio_integrity_intervals(bi, 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 (mempool_initialized(&bs->bio_integrity_pool))
+		return 0;
+
+	if (mempool_init_slab_pool(&bs->bio_integrity_pool,
+				   pool_size, bip_slab))
+		return -1;
+
+	if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
+		mempool_exit(&bs->bio_integrity_pool);
+		return -1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(bioset_integrity_create);
+
+void bioset_integrity_free(struct bio_set *bs)
+{
+	mempool_exit(&bs->bio_integrity_pool);
+	mempool_exit(&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);
+}