1 files changed, 137 insertions, 36 deletions

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 82662f5769c4..bb5da66da4c1 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -46,11 +46,12 @@ static unsigned int dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE
 
 module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, 0644);
 
-static DEFINE_STATIC_KEY_FALSE(use_tasklet_enabled);
+static DEFINE_STATIC_KEY_FALSE(use_bh_wq_enabled);
 
 struct dm_verity_prefetch_work {
 	struct work_struct work;
 	struct dm_verity *v;
+	unsigned short ioprio;
 	sector_t block;
 	unsigned int n_blocks;
 };
@@ -294,10 +295,11 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 	int r;
 	sector_t hash_block;
 	unsigned int offset;
+	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
 
 	verity_hash_at_level(v, block, level, &hash_block, &offset);
 
-	if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) {
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
 		data = dm_bufio_get(v->bufio, hash_block, &buf);
 		if (data == NULL) {
 			/*
@@ -307,8 +309,10 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 			 */
 			return -EAGAIN;
 		}
-	} else
-		data = dm_bufio_read(v->bufio, hash_block, &buf);
+	} else {
+		data = dm_bufio_read_with_ioprio(v->bufio, hash_block,
+						&buf, bio_prio(bio));
+	}
 
 	if (IS_ERR(data))
 		return PTR_ERR(data);
@@ -323,15 +327,14 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 
 		r = verity_hash(v, verity_io_hash_req(v, io),
 				data, 1 << v->hash_dev_block_bits,
-				verity_io_real_digest(v, io), !io->in_tasklet);
+				verity_io_real_digest(v, io), !io->in_bh);
 		if (unlikely(r < 0))
 			goto release_ret_r;
 
 		if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
 				  v->digest_size) == 0))
 			aux->hash_verified = 1;
-		else if (static_branch_unlikely(&use_tasklet_enabled) &&
-			 io->in_tasklet) {
+		else if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
 			/*
 			 * Error handling code (FEC included) cannot be run in a
 			 * tasklet since it may sleep, so fallback to work-queue.
@@ -482,6 +485,63 @@ int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
 	return 0;
 }
 
+static int verity_recheck_copy(struct dm_verity *v, struct dm_verity_io *io,
+			       u8 *data, size_t len)
+{
+	memcpy(data, io->recheck_buffer, len);
+	io->recheck_buffer += len;
+
+	return 0;
+}
+
+static noinline int verity_recheck(struct dm_verity *v, struct dm_verity_io *io,
+				   struct bvec_iter start, sector_t cur_block)
+{
+	struct page *page;
+	void *buffer;
+	int r;
+	struct dm_io_request io_req;
+	struct dm_io_region io_loc;
+
+	page = mempool_alloc(&v->recheck_pool, GFP_NOIO);
+	buffer = page_to_virt(page);
+
+	io_req.bi_opf = REQ_OP_READ;
+	io_req.mem.type = DM_IO_KMEM;
+	io_req.mem.ptr.addr = buffer;
+	io_req.notify.fn = NULL;
+	io_req.client = v->io;
+	io_loc.bdev = v->data_dev->bdev;
+	io_loc.sector = cur_block << (v->data_dev_block_bits - SECTOR_SHIFT);
+	io_loc.count = 1 << (v->data_dev_block_bits - SECTOR_SHIFT);
+	r = dm_io(&io_req, 1, &io_loc, NULL, IOPRIO_DEFAULT);
+	if (unlikely(r))
+		goto free_ret;
+
+	r = verity_hash(v, verity_io_hash_req(v, io), buffer,
+			1 << v->data_dev_block_bits,
+			verity_io_real_digest(v, io), true);
+	if (unlikely(r))
+		goto free_ret;
+
+	if (memcmp(verity_io_real_digest(v, io),
+		   verity_io_want_digest(v, io), v->digest_size)) {
+		r = -EIO;
+		goto free_ret;
+	}
+
+	io->recheck_buffer = buffer;
+	r = verity_for_bv_block(v, io, &start, verity_recheck_copy);
+	if (unlikely(r))
+		goto free_ret;
+
+	r = 0;
+free_ret:
+	mempool_free(page, &v->recheck_pool);
+
+	return r;
+}
+
 static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
 			  u8 *data, size_t len)
 {
@@ -508,16 +568,14 @@ static int verity_verify_io(struct dm_verity_io *io)
 {
 	bool is_zero;
 	struct dm_verity *v = io->v;
-#if defined(CONFIG_DM_VERITY_FEC)
 	struct bvec_iter start;
-#endif
 	struct bvec_iter iter_copy;
 	struct bvec_iter *iter;
 	struct crypto_wait wait;
 	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
 	unsigned int b;
 
-	if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) {
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
 		/*
 		 * Copy the iterator in case we need to restart
 		 * verification in a work-queue.
@@ -557,14 +615,11 @@ static int verity_verify_io(struct dm_verity_io *io)
 			continue;
 		}
 
-		r = verity_hash_init(v, req, &wait, !io->in_tasklet);
+		r = verity_hash_init(v, req, &wait, !io->in_bh);
 		if (unlikely(r < 0))
 			return r;
 
-#if defined(CONFIG_DM_VERITY_FEC)
-		if (verity_fec_is_enabled(v))
-			start = *iter;
-#endif
+		start = *iter;
 		r = verity_for_io_block(v, io, iter, &wait);
 		if (unlikely(r < 0))
 			return r;
@@ -579,13 +634,16 @@ static int verity_verify_io(struct dm_verity_io *io)
 			if (v->validated_blocks)
 				set_bit(cur_block, v->validated_blocks);
 			continue;
-		} else if (static_branch_unlikely(&use_tasklet_enabled) &&
-			   io->in_tasklet) {
+		} else if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
 			/*
 			 * Error handling code (FEC included) cannot be run in a
 			 * tasklet since it may sleep, so fallback to work-queue.
 			 */
 			return -EAGAIN;
+		} else if (verity_recheck(v, io, start, cur_block) == 0) {
+			if (v->validated_blocks)
+				set_bit(cur_block, v->validated_blocks);
+			continue;
 #if defined(CONFIG_DM_VERITY_FEC)
 		} else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
 					     cur_block, NULL, &start) == 0) {
@@ -630,7 +688,7 @@ static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
 	bio->bi_end_io = io->orig_bi_end_io;
 	bio->bi_status = status;
 
-	if (!static_branch_unlikely(&use_tasklet_enabled) || !io->in_tasklet)
+	if (!static_branch_unlikely(&use_bh_wq_enabled) || !io->in_bh)
 		verity_fec_finish_io(io);
 
 	bio_endio(bio);
@@ -640,11 +698,28 @@ static void verity_work(struct work_struct *w)
 {
 	struct dm_verity_io *io = container_of(w, struct dm_verity_io, work);
 
-	io->in_tasklet = false;
+	io->in_bh = false;
 
 	verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
 }
 
+static void verity_bh_work(struct work_struct *w)
+{
+	struct dm_verity_io *io = container_of(w, struct dm_verity_io, bh_work);
+	int err;
+
+	io->in_bh = true;
+	err = verity_verify_io(io);
+	if (err == -EAGAIN || err == -ENOMEM) {
+		/* fallback to retrying with work-queue */
+		INIT_WORK(&io->work, verity_work);
+		queue_work(io->v->verify_wq, &io->work);
+		return;
+	}
+
+	verity_finish_io(io, errno_to_blk_status(err));
+}
+
 static void verity_end_io(struct bio *bio)
 {
 	struct dm_verity_io *io = bio->bi_private;
@@ -657,8 +732,13 @@ static void verity_end_io(struct bio *bio)
 		return;
 	}
 
-	INIT_WORK(&io->work, verity_work);
-	queue_work(io->v->verify_wq, &io->work);
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->v->use_bh_wq) {
+		INIT_WORK(&io->bh_work, verity_bh_work);
+		queue_work(system_bh_wq, &io->bh_work);
+	} else {
+		INIT_WORK(&io->work, verity_work);
+		queue_work(io->v->verify_wq, &io->work);
+	}
 }
 
 /*
@@ -696,14 +776,16 @@ static void verity_prefetch_io(struct work_struct *work)
 				hash_block_end = v->hash_blocks - 1;
 		}
 no_prefetch_cluster:
-		dm_bufio_prefetch(v->bufio, hash_block_start,
-				  hash_block_end - hash_block_start + 1);
+		dm_bufio_prefetch_with_ioprio(v->bufio, hash_block_start,
+					hash_block_end - hash_block_start + 1,
+					pw->ioprio);
 	}
 
 	kfree(pw);
 }
 
-static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
+static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io,
+				   unsigned short ioprio)
 {
 	sector_t block = io->block;
 	unsigned int n_blocks = io->n_blocks;
@@ -731,6 +813,7 @@ static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
 	pw->v = v;
 	pw->block = block;
 	pw->n_blocks = n_blocks;
+	pw->ioprio = ioprio;
 	queue_work(v->verify_wq, &pw->work);
 }
 
@@ -773,7 +856,7 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 
 	verity_fec_init_io(io);
 
-	verity_submit_prefetch(v, io);
+	verity_submit_prefetch(v, io, bio_prio(bio));
 
 	submit_bio_noacct(bio);
 
@@ -822,7 +905,7 @@ static void verity_status(struct dm_target *ti, status_type_t type,
 			args++;
 		if (v->validated_blocks)
 			args++;
-		if (v->use_tasklet)
+		if (v->use_bh_wq)
 			args++;
 		if (v->signature_key_desc)
 			args += DM_VERITY_ROOT_HASH_VERIFICATION_OPTS;
@@ -849,7 +932,7 @@ static void verity_status(struct dm_target *ti, status_type_t type,
 			DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
 		if (v->validated_blocks)
 			DMEMIT(" " DM_VERITY_OPT_AT_MOST_ONCE);
-		if (v->use_tasklet)
+		if (v->use_bh_wq)
 			DMEMIT(" " DM_VERITY_OPT_TASKLET_VERIFY);
 		sz = verity_fec_status_table(v, sz, result, maxlen);
 		if (v->signature_key_desc)
@@ -941,6 +1024,10 @@ static void verity_dtr(struct dm_target *ti)
 	if (v->verify_wq)
 		destroy_workqueue(v->verify_wq);
 
+	mempool_exit(&v->recheck_pool);
+	if (v->io)
+		dm_io_client_destroy(v->io);
+
 	if (v->bufio)
 		dm_bufio_client_destroy(v->bufio);
 
@@ -964,8 +1051,8 @@ static void verity_dtr(struct dm_target *ti)
 
 	kfree(v->signature_key_desc);
 
-	if (v->use_tasklet)
-		static_branch_dec(&use_tasklet_enabled);
+	if (v->use_bh_wq)
+		static_branch_dec(&use_bh_wq_enabled);
 
 	kfree(v);
 
@@ -1099,8 +1186,8 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
 			continue;
 
 		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_TASKLET_VERIFY)) {
-			v->use_tasklet = true;
-			static_branch_inc(&use_tasklet_enabled);
+			v->use_bh_wq = true;
+			static_branch_inc(&use_bh_wq_enabled);
 			continue;
 
 		} else if (verity_is_fec_opt_arg(arg_name)) {
@@ -1271,7 +1358,7 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	v->tfm = crypto_alloc_ahash(v->alg_name, 0,
-				    v->use_tasklet ? CRYPTO_ALG_ASYNC : 0);
+				    v->use_bh_wq ? CRYPTO_ALG_ASYNC : 0);
 	if (IS_ERR(v->tfm)) {
 		ti->error = "Cannot initialize hash function";
 		r = PTR_ERR(v->tfm);
@@ -1379,10 +1466,24 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 	v->hash_blocks = hash_position;
 
+	r = mempool_init_page_pool(&v->recheck_pool, 1, 0);
+	if (unlikely(r)) {
+		ti->error = "Cannot allocate mempool";
+		goto bad;
+	}
+
+	v->io = dm_io_client_create();
+	if (IS_ERR(v->io)) {
+		r = PTR_ERR(v->io);
+		v->io = NULL;
+		ti->error = "Cannot allocate dm io";
+		goto bad;
+	}
+
 	v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
 		1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
 		dm_bufio_alloc_callback, NULL,
-		v->use_tasklet ? DM_BUFIO_CLIENT_NO_SLEEP : 0);
+		v->use_bh_wq ? DM_BUFIO_CLIENT_NO_SLEEP : 0);
 	if (IS_ERR(v->bufio)) {
 		ti->error = "Cannot initialize dm-bufio";
 		r = PTR_ERR(v->bufio);
@@ -1401,7 +1502,7 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	 * reducing wait times when reading from a dm-verity device.
 	 *
 	 * Also as required for the "try_verify_in_tasklet" feature: WQ_HIGHPRI
-	 * allows verify_wq to preempt softirq since verification in tasklet
+	 * allows verify_wq to preempt softirq since verification in BH workqueue
 	 * will fall-back to using it for error handling (or if the bufio cache
 	 * doesn't have required hashes).
 	 */
@@ -1485,8 +1586,8 @@ int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, unsigned i
 
 static struct target_type verity_target = {
 	.name		= "verity",
-	.features	= DM_TARGET_IMMUTABLE,
-	.version	= {1, 9, 0},
+	.features	= DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
+	.version	= {1, 10, 0},
 	.module		= THIS_MODULE,
 	.ctr		= verity_ctr,
 	.dtr		= verity_dtr,