--- /dev/null
+/*
+ * 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>
+
+#define BIP_INLINE_VECS 4
+
+static struct kmem_cache *bip_slab;
+static struct workqueue_struct *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 long idx = BIO_POOL_NONE;
+ unsigned inline_vecs;
+
+ if (!bs) {
+ 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 NULL;
+
+ memset(bip, 0, sizeof(*bip));
+
+ if (nr_vecs > inline_vecs) {
+ 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);
+ } else {
+ bip->bip_vec = bip->bip_inline_vecs;
+ bip->bip_max_vcnt = inline_vecs;
+ }
+
+ bip->bip_slab = idx;
+ bip->bip_bio = bio;
+ bio->bi_integrity = bip;
+ bio->bi_rw |= REQ_INTEGRITY;
+
+ return bip;
+err:
+ mempool_free(bip, bs->bio_integrity_pool);
+ return NULL;
+}
+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().
+ */
+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) {
+ if (bip->bip_slab != BIO_POOL_NONE)
+ 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;
+}
+EXPORT_SYMBOL(bio_integrity_free);
+
+/**
+ * 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;
+
+ 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_enabled - Check whether integrity can be passed
+ * @bio: bio to check
+ *
+ * Description: Determines whether bio_integrity_prep() can be called
+ * on this bio or not. bio data direction and target device must be
+ * set prior to calling. The functions honors the write_generate and
+ * read_verify flags in sysfs.
+ */
+bool bio_integrity_enabled(struct bio *bio)
+{
+ struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+
+ if (!bio_is_rw(bio))
+ return false;
+
+ /* Already protected? */
+ if (bio_integrity(bio))
+ return false;
+
+ if (bi == NULL)
+ return false;
+
+ if (bio_data_dir(bio) == READ && bi->verify_fn != NULL &&
+ (bi->flags & BLK_INTEGRITY_VERIFY))
+ return true;
+
+ if (bio_data_dir(bio) == WRITE && bi->generate_fn != NULL &&
+ (bi->flags & BLK_INTEGRITY_GENERATE))
+ return true;
+
+ return false;
+}
+EXPORT_SYMBOL(bio_integrity_enabled);
+
+/**
+ * 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 >> (ilog2(bi->interval) - 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_fn: Pointer to the relevant processing function
+ */
+static int bio_integrity_process(struct bio *bio,
+ integrity_processing_fn *proc_fn)
+{
+ struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+ struct blk_integrity_iter iter;
+ struct bvec_iter bviter;
+ struct bio_vec bv;
+ struct bio_integrity_payload *bip = bio_integrity(bio);
+ unsigned int ret = 0;
+ void *prot_buf = page_address(bip->bip_vec->bv_page) +
+ bip->bip_vec->bv_offset;
+
+ iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
+ iter.interval = bi->interval;
+ iter.seed = bip_get_seed(bip);
+ iter.prot_buf = prot_buf;
+
+ bio_for_each_segment(bv, bio, bviter) {
+ 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: Allocates a buffer for integrity metadata, maps the
+ * pages and attaches them to a bio. 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.
+ */
+int bio_integrity_prep(struct bio *bio)
+{
+ struct bio_integrity_payload *bip;
+ struct blk_integrity *bi;
+ struct request_queue *q;
+ void *buf;
+ unsigned long start, end;
+ unsigned int len, nr_pages;
+ unsigned int bytes, offset, i;
+ unsigned int intervals;
+
+ bi = bdev_get_integrity(bio->bi_bdev);
+ q = bdev_get_queue(bio->bi_bdev);
+ BUG_ON(bi == NULL);
+ BUG_ON(bio_integrity(bio));
+
+ 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);
+ if (unlikely(buf == NULL)) {
+ printk(KERN_ERR "could not allocate integrity buffer\n");
+ return -ENOMEM;
+ }
+
+ 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 (unlikely(bip == NULL)) {
+ printk(KERN_ERR "could not allocate data integrity bioset\n");
+ kfree(buf);
+ return -EIO;
+ }
+
+ 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 0;
+
+ if (ret < bytes)
+ break;
+
+ buf += bytes;
+ len -= bytes;
+ offset = 0;
+ }
+
+ /* Install custom I/O completion handler if read verify is enabled */
+ if (bio_data_dir(bio) == READ) {
+ bip->bip_end_io = bio->bi_end_io;
+ bio->bi_end_io = bio_integrity_endio;
+ }
+
+ /* Auto-generate integrity metadata if this is a write */
+ if (bio_data_dir(bio) == WRITE)
+ bio_integrity_process(bio, bi->generate_fn);
+
+ return 0;
+}
+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 = bdev_get_integrity(bio->bi_bdev);
+ int error;
+
+ error = bio_integrity_process(bio, bi->verify_fn);
+
+ /* Restore original bio completion handler */
+ bio->bi_end_io = bip->bip_end_io;
+ bio_endio_nodec(bio, error);
+}
+
+/**
+ * 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.
+ */
+void bio_integrity_endio(struct bio *bio, int error)
+{
+ struct bio_integrity_payload *bip = bio_integrity(bio);
+
+ BUG_ON(bip->bip_bio != bio);
+
+ /* In case of an I/O error there is no point in verifying the
+ * integrity metadata. Restore original bio end_io handler
+ * and run it.
+ */
+ if (error) {
+ bio->bi_end_io = bip->bip_end_io;
+ bio_endio_nodec(bio, error);
+
+ return;
+ }
+
+ INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
+ queue_work(kintegrityd_wq, &bip->bip_work);
+}
+EXPORT_SYMBOL(bio_integrity_endio);
+
+/**
+ * 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 = bdev_get_integrity(bio->bi_bdev);
+ unsigned bytes = bio_integrity_bytes(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
+ * @offset: offset to first data sector
+ * @sectors: number of data sectors
+ *
+ * Description: Used to trim the integrity vector in a cloned bio.
+ * The ivec will be advanced corresponding to 'offset' data sectors
+ * and the length will be truncated corresponding to 'len' data
+ * sectors.
+ */
+void bio_integrity_trim(struct bio *bio, unsigned int offset,
+ unsigned int sectors)
+{
+ struct bio_integrity_payload *bip = bio_integrity(bio);
+ struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+
+ bio_integrity_advance(bio, offset << 9);
+ bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
+}
+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 (bip == NULL)
+ return -EIO;
+
+ 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);
+}
Code Review / kvmfornfv.git / blobdiff