dm crypt: simplify crypt_config destruction logic

Use just one label and reuse common destructor for crypt target.

Parse remaining argv arguments in logic order.

Also do not ignore error values from IV init and set key functions.

No functional change in this patch except changed return codes
based on above.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-crypt.c

@@ -999,6 +999,45 @@ static int crypt_wipe_key(struct crypt_config *cc)
 	return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
 }
 
+static void crypt_dtr(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	ti->private = NULL;
+
+	if (!cc)
+		return;
+
+	if (cc->io_queue)
+		destroy_workqueue(cc->io_queue);
+	if (cc->crypt_queue)
+		destroy_workqueue(cc->crypt_queue);
+
+	if (cc->bs)
+		bioset_free(cc->bs);
+
+	if (cc->page_pool)
+		mempool_destroy(cc->page_pool);
+	if (cc->req_pool)
+		mempool_destroy(cc->req_pool);
+	if (cc->io_pool)
+		mempool_destroy(cc->io_pool);
+
+	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+		cc->iv_gen_ops->dtr(cc);
+
+	if (cc->tfm && !IS_ERR(cc->tfm))
+		crypto_free_ablkcipher(cc->tfm);
+
+	if (cc->dev)
+		dm_put_device(ti, cc->dev);
+
+	kfree(cc->iv_mode);
+
+	/* Must zero key material before freeing */
+	kzfree(cc);
+}
+
 /*
  * Construct an encryption mapping:
  * <cipher> <key> <iv_offset> <dev_path> <start>
@@ -1006,7 +1045,6 @@ static int crypt_wipe_key(struct crypt_config *cc)
 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
 	struct crypt_config *cc;
-	struct crypto_ablkcipher *tfm;
 	char *tmp;
 	char *cipher;
 	char *chainmode;
@@ -1014,6 +1052,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	char *ivopts;
 	unsigned int key_size;
 	unsigned long long tmpll;
+	int ret = -EINVAL;
 
 	if (argc != 5) {
 		ti->error = "Not enough arguments";
@@ -1032,12 +1071,13 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	key_size = strlen(argv[1]) >> 1;
 
  	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
-	if (cc == NULL) {
-		ti->error =
-			"Cannot allocate transparent encryption context";
+	if (!cc) {
+		ti->error = "Cannot allocate transparent encryption context";
 		return -ENOMEM;
 	}
 
+	ti->private = cc;
+
 	/* Compatibility mode for old dm-crypt cipher strings */
 	if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
 		chainmode = "cbc";
@@ -1046,35 +1086,36 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	if (strcmp(chainmode, "ecb") && !ivmode) {
 		ti->error = "This chaining mode requires an IV mechanism";
-		goto bad_cipher;
+		goto bad;
 	}
 
+	ret = -ENOMEM;
 	if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
 		     chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
 		ti->error = "Chain mode + cipher name is too long";
-		goto bad_cipher;
+		goto bad;
 	}
 
-	tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
-	if (IS_ERR(tfm)) {
+	cc->tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
+	if (IS_ERR(cc->tfm)) {
 		ti->error = "Error allocating crypto tfm";
-		goto bad_cipher;
+		goto bad;
 	}
 
 	strcpy(cc->cipher, cipher);
 	strcpy(cc->chainmode, chainmode);
-	cc->tfm = tfm;
 
-	if (crypt_set_key(cc, argv[1]) < 0) {
+	ret = crypt_set_key(cc, argv[1]);
+	if (ret < 0) {
 		ti->error = "Error decoding and setting key";
-		goto bad_ivmode;
+		goto bad;
 	}
 
 	/*
 	 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
 	 * See comments at iv code
 	 */
-
+	ret = -EINVAL;
 	if (ivmode == NULL)
 		cc->iv_gen_ops = NULL;
 	else if (strcmp(ivmode, "plain") == 0)
@@ -1089,20 +1130,28 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		cc->iv_gen_ops = &crypt_iv_null_ops;
 	else {
 		ti->error = "Invalid IV mode";
-		goto bad_ivmode;
+		goto bad;
 	}
 
-	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
-	    cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
-		goto bad_ivmode;
+	/* Allocate IV */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
+		ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
+		if (ret < 0) {
+			ti->error = "Error creating IV";
+			goto bad;
+		}
+	}
 
-	if (cc->iv_gen_ops && cc->iv_gen_ops->init &&
-	    cc->iv_gen_ops->init(cc) < 0) {
-		ti->error = "Error initialising IV";
-		goto bad_slab_pool;
+	/* Initialize IV (set keys for ESSIV etc) */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
+		ret = cc->iv_gen_ops->init(cc);
+		if (ret < 0) {
+			ti->error = "Error initialising IV";
+			goto bad;
+		}
 	}
 
-	cc->iv_size = crypto_ablkcipher_ivsize(tfm);
+	cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
 	if (cc->iv_size)
 		/* at least a 64 bit sector number should fit in our buffer */
 		cc->iv_size = max(cc->iv_size,
@@ -1116,62 +1165,65 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		}
 	}
 
+	ret = -ENOMEM;
 	cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
 	if (!cc->io_pool) {
 		ti->error = "Cannot allocate crypt io mempool";
-		goto bad_slab_pool;
+		goto bad;
 	}
 
 	cc->dmreq_start = sizeof(struct ablkcipher_request);
-	cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
+	cc->dmreq_start += crypto_ablkcipher_reqsize(cc->tfm);
 	cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
-	cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
+	cc->dmreq_start += crypto_ablkcipher_alignmask(cc->tfm) &
 			   ~(crypto_tfm_ctx_alignment() - 1);
 
 	cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
 			sizeof(struct dm_crypt_request) + cc->iv_size);
 	if (!cc->req_pool) {
 		ti->error = "Cannot allocate crypt request mempool";
-		goto bad_req_pool;
+		goto bad;
 	}
 	cc->req = NULL;
 
 	cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
 	if (!cc->page_pool) {
 		ti->error = "Cannot allocate page mempool";
-		goto bad_page_pool;
+		goto bad;
 	}
 
 	cc->bs = bioset_create(MIN_IOS, 0);
 	if (!cc->bs) {
 		ti->error = "Cannot allocate crypt bioset";
-		goto bad_bs;
+		goto bad;
 	}
 
+	ret = -EINVAL;
 	if (sscanf(argv[2], "%llu", &tmpll) != 1) {
 		ti->error = "Invalid iv_offset sector";
-		goto bad_device;
+		goto bad;
 	}
 	cc->iv_offset = tmpll;
 
+	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
+		ti->error = "Device lookup failed";
+		goto bad;
+	}
+
 	if (sscanf(argv[4], "%llu", &tmpll) != 1) {
 		ti->error = "Invalid device sector";
-		goto bad_device;
+		goto bad;
 	}
 	cc->start = tmpll;
 
-	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
-		ti->error = "Device lookup failed";
-		goto bad_device;
-	}
-
+	ret = -ENOMEM;
 	if (ivmode && cc->iv_gen_ops) {
 		if (ivopts)
 			*(ivopts - 1) = ':';
 		cc->iv_mode = kstrdup(ivmode, GFP_KERNEL);
 		if (!cc->iv_mode) {
 			ti->error = "Error kmallocing iv_mode string";
-			goto bad_ivmode_string;
+			goto bad;
 		}
 	} else
 		cc->iv_mode = NULL;
@@ -1179,67 +1231,21 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	cc->io_queue = create_singlethread_workqueue("kcryptd_io");
 	if (!cc->io_queue) {
 		ti->error = "Couldn't create kcryptd io queue";
-		goto bad_io_queue;
+		goto bad;
 	}
 
 	cc->crypt_queue = create_singlethread_workqueue("kcryptd");
 	if (!cc->crypt_queue) {
 		ti->error = "Couldn't create kcryptd queue";
-		goto bad_crypt_queue;
+		goto bad;
 	}
 
 	ti->num_flush_requests = 1;
-	ti->private = cc;
 	return 0;
 
-bad_crypt_queue:
-	destroy_workqueue(cc->io_queue);
-bad_io_queue:
-	kfree(cc->iv_mode);
-bad_ivmode_string:
-	dm_put_device(ti, cc->dev);
-bad_device:
-	bioset_free(cc->bs);
-bad_bs:
-	mempool_destroy(cc->page_pool);
-bad_page_pool:
-	mempool_destroy(cc->req_pool);
-bad_req_pool:
-	mempool_destroy(cc->io_pool);
-bad_slab_pool:
-	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
-		cc->iv_gen_ops->dtr(cc);
-bad_ivmode:
-	crypto_free_ablkcipher(tfm);
-bad_cipher:
-	/* Must zero key material before freeing */
-	kzfree(cc);
-	return -EINVAL;
-}
-
-static void crypt_dtr(struct dm_target *ti)
-{
-	struct crypt_config *cc = (struct crypt_config *) ti->private;
-
-	destroy_workqueue(cc->io_queue);
-	destroy_workqueue(cc->crypt_queue);
-
-	if (cc->req)
-		mempool_free(cc->req, cc->req_pool);
-
-	bioset_free(cc->bs);
-	mempool_destroy(cc->page_pool);
-	mempool_destroy(cc->req_pool);
-	mempool_destroy(cc->io_pool);
-
-	kfree(cc->iv_mode);
-	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
-		cc->iv_gen_ops->dtr(cc);
-	crypto_free_ablkcipher(cc->tfm);
-	dm_put_device(ti, cc->dev);
-
-	/* Must zero key material before freeing */
-	kzfree(cc);
+bad:
+	crypt_dtr(ti);
+	return ret;
 }
 
 static int crypt_map(struct dm_target *ti, struct bio *bio,