Merge tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - A major update for DM cache that reduces the latency for deciding
   whether blocks should migrate to/from the cache. The bio-prison-v2
   interface supports this improvement by enabling direct dispatch of
   work to workqueues rather than having to delay the actual work
   dispatch to the DM cache core. So the dm-cache policies are much more
   nimble by being able to drive IO as they see fit. One immediate
   benefit from the improved latency is a cache that should be much more
   adaptive to changing workloads.

 - Add a new DM integrity target that emulates a block device that has
   additional per-sector tags that can be used for storing integrity
   information.

 - Add a new authenticated encryption feature to the DM crypt target
   that builds on the capabilities provided by the DM integrity target.

 - Add MD interface for switching the raid4/5/6 journal mode and update
   the DM raid target to use it to enable aid4/5/6 journal write-back
   support.

 - Switch the DM verity target over to using the asynchronous hash
   crypto API (this helps work better with architectures that have
   access to off-CPU algorithm providers, which should reduce CPU
   utilization).

 - Various request-based DM and DM multipath fixes and improvements from
   Bart and Christoph.

 - A DM thinp target fix for a bio structure leak that occurs for each
   discard IFF discard passdown is enabled.

 - A fix for a possible deadlock in DM bufio and a fix to re-check the
   new buffer allocation watermark in the face of competing admin
   changes to the 'max_cache_size_bytes' tunable.

 - A couple DM core cleanups.

* tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits)
  dm bufio: check new buffer allocation watermark every 30 seconds
  dm bufio: avoid a possible ABBA deadlock
  dm mpath: make it easier to detect unintended I/O request flushes
  dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit()
  dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH
  dm: introduce enum dm_queue_mode to cleanup related code
  dm mpath: verify __pg_init_all_paths locking assumptions at runtime
  dm: verify suspend_locking assumptions at runtime
  dm block manager: remove an unused argument from dm_block_manager_create()
  dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue()
  dm mpath: delay requeuing while path initialization is in progress
  dm mpath: avoid that path removal can trigger an infinite loop
  dm mpath: split and rename activate_path() to prepare for its expanded use
  dm ioctl: prevent stack leak in dm ioctl call
  dm integrity: use previously calculated log2 of sectors_per_block
  dm integrity: use hex2bin instead of open-coded variant
  dm crypt: replace custom implementation of hex2bin()
  dm crypt: remove obsolete references to per-CPU state
  dm verity: switch to using asynchronous hash crypto API
  dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues
  ...

1 files changed, 141 insertions, 60 deletions

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 7335d8a3fc47..97de961a3bfc 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -93,81 +93,123 @@ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
 }
 
 /*
- * Wrapper for crypto_shash_init, which handles verity salting.
+ * Callback function for asynchrnous crypto API completion notification
  */
-static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc)
+static void verity_op_done(struct crypto_async_request *base, int err)
 {
-	int r;
+	struct verity_result *res = (struct verity_result *)base->data;
 
-	desc->tfm = v->tfm;
-	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+	if (err == -EINPROGRESS)
+		return;
 
-	r = crypto_shash_init(desc);
+	res->err = err;
+	complete(&res->completion);
+}
 
-	if (unlikely(r < 0)) {
-		DMERR("crypto_shash_init failed: %d", r);
-		return r;
-	}
+/*
+ * Wait for async crypto API callback
+ */
+static inline int verity_complete_op(struct verity_result *res, int ret)
+{
+	switch (ret) {
+	case 0:
+		break;
 
-	if (likely(v->version >= 1)) {
-		r = crypto_shash_update(desc, v->salt, v->salt_size);
+	case -EINPROGRESS:
+	case -EBUSY:
+		ret = wait_for_completion_interruptible(&res->completion);
+		if (!ret)
+			ret = res->err;
+		reinit_completion(&res->completion);
+		break;
 
-		if (unlikely(r < 0)) {
-			DMERR("crypto_shash_update failed: %d", r);
-			return r;
-		}
+	default:
+		DMERR("verity_wait_hash: crypto op submission failed: %d", ret);
 	}
 
-	return 0;
+	if (unlikely(ret < 0))
+		DMERR("verity_wait_hash: crypto op failed: %d", ret);
+
+	return ret;
 }
 
-static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc,
-			      const u8 *data, size_t len)
+static int verity_hash_update(struct dm_verity *v, struct ahash_request *req,
+				const u8 *data, size_t len,
+				struct verity_result *res)
 {
-	int r = crypto_shash_update(desc, data, len);
+	struct scatterlist sg;
 
-	if (unlikely(r < 0))
-		DMERR("crypto_shash_update failed: %d", r);
+	sg_init_one(&sg, data, len);
+	ahash_request_set_crypt(req, &sg, NULL, len);
+
+	return verity_complete_op(res, crypto_ahash_update(req));
+}
+
+/*
+ * Wrapper for crypto_ahash_init, which handles verity salting.
+ */
+static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,
+				struct verity_result *res)
+{
+	int r;
+
+	ahash_request_set_tfm(req, v->tfm);
+	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
+					CRYPTO_TFM_REQ_MAY_BACKLOG,
+					verity_op_done, (void *)res);
+	init_completion(&res->completion);
+
+	r = verity_complete_op(res, crypto_ahash_init(req));
+
+	if (unlikely(r < 0)) {
+		DMERR("crypto_ahash_init failed: %d", r);
+		return r;
+	}
+
+	if (likely(v->version >= 1))
+		r = verity_hash_update(v, req, v->salt, v->salt_size, res);
 
 	return r;
 }
 
-static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc,
-			     u8 *digest)
+static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,
+			     u8 *digest, struct verity_result *res)
 {
 	int r;
 
 	if (unlikely(!v->version)) {
-		r = crypto_shash_update(desc, v->salt, v->salt_size);
+		r = verity_hash_update(v, req, v->salt, v->salt_size, res);
 
 		if (r < 0) {
-			DMERR("crypto_shash_update failed: %d", r);
-			return r;
+			DMERR("verity_hash_final failed updating salt: %d", r);
+			goto out;
 		}
 	}
 
-	r = crypto_shash_final(desc, digest);
-
-	if (unlikely(r < 0))
-		DMERR("crypto_shash_final failed: %d", r);
-
+	ahash_request_set_crypt(req, NULL, digest, 0);
+	r = verity_complete_op(res, crypto_ahash_final(req));
+out:
 	return r;
 }
 
-int verity_hash(struct dm_verity *v, struct shash_desc *desc,
+int verity_hash(struct dm_verity *v, struct ahash_request *req,
 		const u8 *data, size_t len, u8 *digest)
 {
 	int r;
+	struct verity_result res;
 
-	r = verity_hash_init(v, desc);
+	r = verity_hash_init(v, req, &res);
 	if (unlikely(r < 0))
-		return r;
+		goto out;
 
-	r = verity_hash_update(v, desc, data, len);
+	r = verity_hash_update(v, req, data, len, &res);
 	if (unlikely(r < 0))
-		return r;
+		goto out;
+
+	r = verity_hash_final(v, req, digest, &res);
 
-	return verity_hash_final(v, desc, digest);
+out:
+	return r;
 }
 
 static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
@@ -275,7 +317,7 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 			goto release_ret_r;
 		}
 
-		r = verity_hash(v, verity_io_hash_desc(v, io),
+		r = verity_hash(v, verity_io_hash_req(v, io),
 				data, 1 << v->hash_dev_block_bits,
 				verity_io_real_digest(v, io));
 		if (unlikely(r < 0))
@@ -344,6 +386,49 @@ out:
 }
 
 /*
+ * Calculates the digest for the given bio
+ */
+int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io,
+			struct bvec_iter *iter, struct verity_result *res)
+{
+	unsigned int todo = 1 << v->data_dev_block_bits;
+	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
+	struct scatterlist sg;
+	struct ahash_request *req = verity_io_hash_req(v, io);
+
+	do {
+		int r;
+		unsigned int len;
+		struct bio_vec bv = bio_iter_iovec(bio, *iter);
+
+		sg_init_table(&sg, 1);
+
+		len = bv.bv_len;
+
+		if (likely(len >= todo))
+			len = todo;
+		/*
+		 * Operating on a single page at a time looks suboptimal
+		 * until you consider the typical block size is 4,096B.
+		 * Going through this loops twice should be very rare.
+		 */
+		sg_set_page(&sg, bv.bv_page, len, bv.bv_offset);
+		ahash_request_set_crypt(req, &sg, NULL, len);
+		r = verity_complete_op(res, crypto_ahash_update(req));
+
+		if (unlikely(r < 0)) {
+			DMERR("verity_for_io_block crypto op failed: %d", r);
+			return r;
+		}
+
+		bio_advance_iter(bio, iter, len);
+		todo -= len;
+	} while (todo);
+
+	return 0;
+}
+
+/*
  * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec
  * starting from iter.
  */
@@ -381,12 +466,6 @@ int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
 	return 0;
 }
 
-static int verity_bv_hash_update(struct dm_verity *v, struct dm_verity_io *io,
-				 u8 *data, size_t len)
-{
-	return verity_hash_update(v, verity_io_hash_desc(v, io), data, len);
-}
-
 static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
 			  u8 *data, size_t len)
 {
@@ -403,10 +482,11 @@ static int verity_verify_io(struct dm_verity_io *io)
 	struct dm_verity *v = io->v;
 	struct bvec_iter start;
 	unsigned b;
+	struct verity_result res;
 
 	for (b = 0; b < io->n_blocks; b++) {
 		int r;
-		struct shash_desc *desc = verity_io_hash_desc(v, io);
+		struct ahash_request *req = verity_io_hash_req(v, io);
 
 		r = verity_hash_for_block(v, io, io->block + b,
 					  verity_io_want_digest(v, io),
@@ -427,16 +507,17 @@ static int verity_verify_io(struct dm_verity_io *io)
 			continue;
 		}
 
-		r = verity_hash_init(v, desc);
+		r = verity_hash_init(v, req, &res);
 		if (unlikely(r < 0))
 			return r;
 
 		start = io->iter;
-		r = verity_for_bv_block(v, io, &io->iter, verity_bv_hash_update);
+		r = verity_for_io_block(v, io, &io->iter, &res);
 		if (unlikely(r < 0))
 			return r;
 
-		r = verity_hash_final(v, desc, verity_io_real_digest(v, io));
+		r = verity_hash_final(v, req, verity_io_real_digest(v, io),
+					&res);
 		if (unlikely(r < 0))
 			return r;
 
@@ -705,7 +786,7 @@ static void verity_dtr(struct dm_target *ti)
 	kfree(v->zero_digest);
 
 	if (v->tfm)
-		crypto_free_shash(v->tfm);
+		crypto_free_ahash(v->tfm);
 
 	kfree(v->alg_name);
 
@@ -723,7 +804,7 @@ static void verity_dtr(struct dm_target *ti)
 static int verity_alloc_zero_digest(struct dm_verity *v)
 {
 	int r = -ENOMEM;
-	struct shash_desc *desc;
+	struct ahash_request *req;
 	u8 *zero_data;
 
 	v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
@@ -731,9 +812,9 @@ static int verity_alloc_zero_digest(struct dm_verity *v)
 	if (!v->zero_digest)
 		return r;
 
-	desc = kmalloc(v->shash_descsize, GFP_KERNEL);
+	req = kmalloc(v->ahash_reqsize, GFP_KERNEL);
 
-	if (!desc)
+	if (!req)
 		return r; /* verity_dtr will free zero_digest */
 
 	zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
@@ -741,11 +822,11 @@ static int verity_alloc_zero_digest(struct dm_verity *v)
 	if (!zero_data)
 		goto out;
 
-	r = verity_hash(v, desc, zero_data, 1 << v->data_dev_block_bits,
+	r = verity_hash(v, req, zero_data, 1 << v->data_dev_block_bits,
 			v->zero_digest);
 
 out:
-	kfree(desc);
+	kfree(req);
 	kfree(zero_data);
 
 	return r;
@@ -923,21 +1004,21 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		goto bad;
 	}
 
-	v->tfm = crypto_alloc_shash(v->alg_name, 0, 0);
+	v->tfm = crypto_alloc_ahash(v->alg_name, 0, 0);
 	if (IS_ERR(v->tfm)) {
 		ti->error = "Cannot initialize hash function";
 		r = PTR_ERR(v->tfm);
 		v->tfm = NULL;
 		goto bad;
 	}
-	v->digest_size = crypto_shash_digestsize(v->tfm);
+	v->digest_size = crypto_ahash_digestsize(v->tfm);
 	if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
 		ti->error = "Digest size too big";
 		r = -EINVAL;
 		goto bad;
 	}
-	v->shash_descsize =
-		sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm);
+	v->ahash_reqsize = sizeof(struct ahash_request) +
+		crypto_ahash_reqsize(v->tfm);
 
 	v->root_digest = kmalloc(v->digest_size, GFP_KERNEL);
 	if (!v->root_digest) {
@@ -1037,7 +1118,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	}
 
 	ti->per_io_data_size = sizeof(struct dm_verity_io) +
-				v->shash_descsize + v->digest_size * 2;
+				v->ahash_reqsize + v->digest_size * 2;
 
 	r = verity_fec_ctr(v);
 	if (r)