@@ -18,6 +18,7 @@
#include <linux/crypto.h>
#include <linux/workqueue.h>
#include <linux/backing-dev.h>
+#include <linux/percpu.h>
#include <asm/atomic.h>
#include <linux/scatterlist.h>
#include <asm/page.h>
@@ -77,11 +78,15 @@ struct crypt_iv_operations {
};
struct iv_essiv_private {
- struct crypto_cipher *tfm;
struct crypto_hash *hash_tfm;
u8 *salt;
};
+/* Duplicated per CPU state for cipher */
+struct iv_essiv_private_cpu {
+ struct crypto_cipher *tfm;
+};
+
struct iv_benbi_private {
int shift;
};
@@ -91,6 +96,18 @@ struct iv_benbi_private {
* and encrypts / decrypts at the same time.
*/
enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
+
+/* Duplicated per CPU state for cipher */
+struct crypt_cpu {
+ struct ablkcipher_request *req;
+ struct crypto_ablkcipher *tfm;
+ struct iv_essiv_private_cpu ie;
+};
+
+/*
+ * The fields in here must be read only after initialization,
+ * changing state should be in crypt_cpu.
+ */
struct crypt_config {
struct dm_dev *dev;
sector_t start;
@@ -103,10 +120,6 @@ struct crypt_config {
mempool_t *req_pool;
mempool_t *page_pool;
struct bio_set *bs;
-
- struct workqueue_struct *io_queue;
- struct workqueue_struct *crypt_queue;
-
/*
* crypto related data
*/
@@ -120,6 +133,12 @@ struct crypt_config {
unsigned int iv_size;
/*
+ * Duplicated per cpu state. Access through
+ * per_cpu_ptr() only.
+ */
+ struct crypt_cpu __percpu *cpu;
+
+ /*
* Layout of each crypto request:
*
* struct ablkcipher_request
@@ -133,25 +152,44 @@ struct crypt_config {
* correctly aligned.
*/
unsigned int dmreq_start;
- struct ablkcipher_request *req;
char cipher[CRYPTO_MAX_ALG_NAME];
char chainmode[CRYPTO_MAX_ALG_NAME];
- struct crypto_ablkcipher *tfm;
unsigned long flags;
unsigned int key_size;
u8 key[0];
};
+/* RED-PEN scale with number of cpus? */
#define MIN_IOS 16
#define MIN_POOL_PAGES 32
#define MIN_BIO_PAGES 8
+/* Protect creation of a new crypt queue */
+static DEFINE_MUTEX(queue_setup_lock);
+static struct workqueue_struct *crypt_workqueue;
+static struct workqueue_struct *io_workqueue;
+static DEFINE_PER_CPU(struct task_struct *, io_wq_cpu);
+
static struct kmem_cache *_crypt_io_pool;
static void clone_init(struct dm_crypt_io *, struct bio *);
static void kcryptd_queue_crypt(struct dm_crypt_io *io);
+static struct crypt_cpu *crypt_me(struct crypt_config *cc)
+{
+ return this_cpu_ptr(cc->cpu);
+}
+
+/* Use this for cipher attributes that are the same for all cpus */
+static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
+{
+ struct crypto_ablkcipher *tfm;
+ /* cpu doesn't matter, output is always the same */
+ tfm = __this_cpu_ptr(cc->cpu)->tfm;
+ return tfm;
+}
+
/*
* Different IV generation algorithms:
*
@@ -198,7 +236,7 @@ static int crypt_iv_essiv_init(struct crypt_config *cc)
struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
struct hash_desc desc;
struct scatterlist sg;
- int err;
+ int err, n, cpu;
sg_init_one(&sg, cc->key, cc->key_size);
desc.tfm = essiv->hash_tfm;
@@ -208,8 +246,18 @@ static int crypt_iv_essiv_init(struct crypt_config *cc)
if (err)
return err;
- return crypto_cipher_setkey(essiv->tfm, essiv->salt,
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+
+ n = crypto_cipher_setkey(cs->ie.tfm, essiv->salt,
crypto_hash_digestsize(essiv->hash_tfm));
+ if (n) {
+ err = n;
+ break;
+ }
+ }
+
+ return err;
}
/* Wipe salt and reset key derived from volume key */
@@ -217,24 +265,70 @@ static int crypt_iv_essiv_wipe(struct crypt_config *cc)
{
struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
+ int cpu, err, n;
memset(essiv->salt, 0, salt_size);
- return crypto_cipher_setkey(essiv->tfm, essiv->salt, salt_size);
+ err = 0;
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+ n = crypto_cipher_setkey(cs->ie.tfm, essiv->salt, salt_size);
+ if (n)
+ err = n;
+ }
+ return err;
+}
+
+/* Set up per cpu cipher state */
+static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
+ struct dm_target *ti,
+ u8 *salt, unsigned saltsize)
+{
+ struct crypto_cipher *essiv_tfm;
+ int err;
+
+ /* Setup the essiv_tfm with the given salt */
+ essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(essiv_tfm)) {
+ ti->error = "Error allocating crypto tfm for ESSIV";
+ return essiv_tfm;
+ }
+
+ if (crypto_cipher_blocksize(essiv_tfm) !=
+ crypto_ablkcipher_ivsize(any_tfm(cc))) {
+ ti->error = "Block size of ESSIV cipher does "
+ "not match IV size of block cipher";
+ crypto_free_cipher(essiv_tfm);
+ return ERR_PTR(-EINVAL);
+ }
+ err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
+ if (err) {
+ ti->error = "Failed to set key for ESSIV cipher";
+ crypto_free_cipher(essiv_tfm);
+ return ERR_PTR(err);
+ }
+
+ return essiv_tfm;
}
static void crypt_iv_essiv_dtr(struct crypt_config *cc)
{
+ int cpu;
struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
- crypto_free_cipher(essiv->tfm);
- essiv->tfm = NULL;
-
crypto_free_hash(essiv->hash_tfm);
essiv->hash_tfm = NULL;
kzfree(essiv->salt);
essiv->salt = NULL;
+
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+ if (cs->ie.tfm) {
+ crypto_free_cipher(cs->ie.tfm);
+ cs->ie.tfm = NULL;
+ }
+ }
}
static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
@@ -244,6 +338,7 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
struct crypto_hash *hash_tfm = NULL;
u8 *salt = NULL;
int err;
+ int cpu;
if (!opts) {
ti->error = "Digest algorithm missing for ESSIV mode";
@@ -265,30 +360,22 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
goto bad;
}
- /* Allocate essiv_tfm */
- essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(essiv_tfm)) {
- ti->error = "Error allocating crypto tfm for ESSIV";
- err = PTR_ERR(essiv_tfm);
- goto bad;
- }
- if (crypto_cipher_blocksize(essiv_tfm) !=
- crypto_ablkcipher_ivsize(cc->tfm)) {
- ti->error = "Block size of ESSIV cipher does "
- "not match IV size of block cipher";
- err = -EINVAL;
- goto bad;
- }
-
cc->iv_gen_private.essiv.salt = salt;
- cc->iv_gen_private.essiv.tfm = essiv_tfm;
cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
+ for_each_possible_cpu (cpu) {
+ essiv_tfm = setup_essiv_cpu(cc, ti, salt,
+ crypto_hash_digestsize(hash_tfm));
+ if (IS_ERR(essiv_tfm)) {
+ kfree(salt);
+ crypt_iv_essiv_dtr(cc);
+ return PTR_ERR(essiv_tfm);
+ }
+ per_cpu_ptr(cc->cpu, cpu)->ie.tfm = essiv_tfm;
+ }
return 0;
bad:
- if (essiv_tfm && !IS_ERR(essiv_tfm))
- crypto_free_cipher(essiv_tfm);
if (hash_tfm && !IS_ERR(hash_tfm))
crypto_free_hash(hash_tfm);
kfree(salt);
@@ -299,14 +386,14 @@ static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
memset(iv, 0, cc->iv_size);
*(u64 *)iv = cpu_to_le64(sector);
- crypto_cipher_encrypt_one(cc->iv_gen_private.essiv.tfm, iv, iv);
+ crypto_cipher_encrypt_one(crypt_me(cc)->ie.tfm, iv, iv);
return 0;
}
static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
const char *opts)
{
- unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
+ unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
int log = ilog2(bs);
/* we need to calculate how far we must shift the sector count
@@ -415,7 +502,7 @@ static int crypt_convert_block(struct crypt_config *cc,
dmreq = dmreq_of_req(cc, req);
iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
- crypto_ablkcipher_alignmask(cc->tfm) + 1);
+ crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
dmreq->ctx = ctx;
sg_init_table(&dmreq->sg_in, 1);
@@ -460,13 +547,14 @@ static void kcryptd_async_done(struct crypto_async_request *async_req,
static void crypt_alloc_req(struct crypt_config *cc,
struct convert_context *ctx)
{
- if (!cc->req)
- cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
- ablkcipher_request_set_tfm(cc->req, cc->tfm);
- ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+ struct crypt_cpu *cs = crypt_me(cc);
+ if (!cs->req)
+ cs->req = mempool_alloc(cc->req_pool, GFP_NOIO);
+ ablkcipher_request_set_tfm(cs->req, cs->tfm);
+ ablkcipher_request_set_callback(cs->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
kcryptd_async_done,
- dmreq_of_req(cc, cc->req));
+ dmreq_of_req(cc, cs->req));
}
/*
@@ -475,6 +563,7 @@ static void crypt_alloc_req(struct crypt_config *cc,
static int crypt_convert(struct crypt_config *cc,
struct convert_context *ctx)
{
+ struct crypt_cpu *cs = crypt_me(cc);
int r;
atomic_set(&ctx->pending, 1);
@@ -486,7 +575,7 @@ static int crypt_convert(struct crypt_config *cc,
atomic_inc(&ctx->pending);
- r = crypt_convert_block(cc, ctx, cc->req);
+ r = crypt_convert_block(cc, ctx, cs->req);
switch (r) {
/* async */
@@ -495,7 +584,7 @@ static int crypt_convert(struct crypt_config *cc,
INIT_COMPLETION(ctx->restart);
/* fall through*/
case -EINPROGRESS:
- cc->req = NULL;
+ cs->req = NULL;
ctx->sector++;
continue;
@@ -654,6 +743,9 @@ static void crypt_dec_pending(struct dm_crypt_io *io)
* They must be separated as otherwise the final stages could be
* starved by new requests which can block in the first stages due
* to memory allocation.
+ *
+ * The work is done per CPU global for all dmcrypt instances.
+ * They should not depend on each other and do not block.
*/
static void crypt_endio(struct bio *clone, int error)
{
@@ -735,6 +827,7 @@ static void kcryptd_io(struct work_struct *work)
{
struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
+ __this_cpu_write(io_wq_cpu, current);
if (bio_data_dir(io->base_bio) == READ)
kcryptd_io_read(io);
else
@@ -743,10 +836,23 @@ static void kcryptd_io(struct work_struct *work)
static void kcryptd_queue_io(struct dm_crypt_io *io)
{
- struct crypt_config *cc = io->target->private;
+ int cpu;
+
+ /*
+ * Since we only have a single worker per CPU in extreme
+ * cases there might be nesting (dm-crypt on another dm-crypt)
+ * To avoid deadlock run the work directly then.
+ */
+ cpu = get_cpu();
+ if (per_cpu(io_wq_cpu, cpu) == current && !in_interrupt()) {
+ put_cpu();
+ kcryptd_io(&io->work);
+ return;
+ }
INIT_WORK(&io->work, kcryptd_io);
- queue_work(cc->io_queue, &io->work);
+ queue_work(io_workqueue, &io->work);
+ put_cpu();
}
static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
@@ -927,10 +1033,8 @@ static void kcryptd_crypt(struct work_struct *work)
static void kcryptd_queue_crypt(struct dm_crypt_io *io)
{
- struct crypt_config *cc = io->target->private;
-
INIT_WORK(&io->work, kcryptd_crypt);
- queue_work(cc->crypt_queue, &io->work);
+ queue_work(crypt_workqueue, &io->work);
}
/*
@@ -974,6 +1078,21 @@ static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
}
}
+static int crypt_setkey_allcpus(struct crypt_config *cc)
+{
+ int cpu, n, err;
+
+ err = 0;
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+ n = crypto_ablkcipher_setkey(cs->tfm, cc->key, cc->key_size);
+ if (n)
+ err = n;
+ }
+ return err;
+}
+
+
static int crypt_set_key(struct crypt_config *cc, char *key)
{
unsigned key_size = strlen(key) >> 1;
@@ -989,14 +1108,48 @@ static int crypt_set_key(struct crypt_config *cc, char *key)
set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
- return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
+ return crypt_setkey_allcpus(cc);
}
static int crypt_wipe_key(struct crypt_config *cc)
{
clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
memset(&cc->key, 0, cc->key_size * sizeof(u8));
- return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
+ return crypt_setkey_allcpus(cc);
+}
+
+/* Use a global per-CPU encryption workqueue for all mounts */
+static int crypt_create_workqueues(void)
+{
+ int ret = 0;
+
+ /* Module unload cleans up on error */
+ mutex_lock(&queue_setup_lock);
+ if (!crypt_workqueue) {
+ crypt_workqueue = create_workqueue("dmcrypt");
+ if (!crypt_workqueue)
+ ret = -ENOMEM;
+ }
+ if (!io_workqueue) {
+ io_workqueue = create_workqueue("dmcrypt-io");
+ if (!io_workqueue)
+ ret = -ENOMEM;
+ }
+ mutex_unlock(&queue_setup_lock);
+ return ret;
+}
+
+static void crypt_dtr_cpus(struct crypt_config *cc)
+{
+ int cpu;
+
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+ if (cs->tfm) {
+ crypto_free_ablkcipher(cs->tfm);
+ cs->tfm = NULL;
+ }
+ }
}
/*
@@ -1014,6 +1167,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
char *ivopts;
unsigned int key_size;
unsigned long long tmpll;
+ int cpu;
if (argc != 5) {
ti->error = "Not enough arguments";
@@ -1038,7 +1192,13 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
return -ENOMEM;
}
- /* Compatibility mode for old dm-crypt cipher strings */
+ cc->cpu = alloc_percpu(struct crypt_cpu);
+ if (!cc->cpu) {
+ ti->error = "Cannot allocate per cpu state";
+ goto bad_percpu;
+ }
+
+ /* Compatiblity mode for old dm-crypt cipher strings */
if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
chainmode = "cbc";
ivmode = "plain";
@@ -1055,15 +1215,18 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_cipher;
}
- tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
- if (IS_ERR(tfm)) {
- ti->error = "Error allocating crypto tfm";
- goto bad_cipher;
+ for_each_possible_cpu (cpu) {
+ tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
+ if (IS_ERR(tfm)) {
+ ti->error = "Error allocating crypto tfm";
+ goto bad_ivmode;
+ }
+ per_cpu_ptr(cc->cpu, cpu)->tfm = tfm;
}
+ tfm = any_tfm(cc);
strcpy(cc->cipher, cipher);
strcpy(cc->chainmode, chainmode);
- cc->tfm = tfm;
if (crypt_set_key(cc, argv[1]) < 0) {
ti->error = "Error decoding and setting key";
@@ -1134,7 +1297,6 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
ti->error = "Cannot allocate crypt request mempool";
goto bad_req_pool;
}
- cc->req = NULL;
cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
if (!cc->page_pool) {
@@ -1148,6 +1310,14 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_bs;
}
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+ if (crypto_ablkcipher_setkey(cs->tfm, cc->key, key_size) < 0) {
+ ti->error = "Error setting key";
+ goto bad_device;
+ }
+ }
+
if (sscanf(argv[2], "%llu", &tmpll) != 1) {
ti->error = "Invalid iv_offset sector";
goto bad_device;
@@ -1177,25 +1347,16 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
} else
cc->iv_mode = NULL;
- cc->io_queue = create_singlethread_workqueue("kcryptd_io");
- if (!cc->io_queue) {
- ti->error = "Couldn't create kcryptd io queue";
- goto bad_io_queue;
- }
-
- cc->crypt_queue = create_singlethread_workqueue("kcryptd");
- if (!cc->crypt_queue) {
- ti->error = "Couldn't create kcryptd queue";
- goto bad_crypt_queue;
+ if (crypt_create_workqueues() < 0) {
+ ti->error = "Couldn't create kcrypt work queues";
+ goto bad_queues;
}
ti->num_flush_requests = 1;
ti->private = cc;
return 0;
-bad_crypt_queue:
- destroy_workqueue(cc->io_queue);
-bad_io_queue:
+bad_queues:
kfree(cc->iv_mode);
bad_ivmode_string:
dm_put_device(ti, cc->dev);
@@ -1211,8 +1372,10 @@ 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);
+ crypt_dtr_cpus(cc);
bad_cipher:
+ free_percpu(cc->cpu);
+bad_percpu:
/* Must zero key material before freeing */
kzfree(cc);
return -EINVAL;
@@ -1220,13 +1383,14 @@ bad_cipher:
static void crypt_dtr(struct dm_target *ti)
{
+ int cpu;
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);
+ for_each_possible_cpu (cpu) {
+ struct crypt_cpu *cs = per_cpu_ptr(cc->cpu, cpu);
+ if (cs->req)
+ mempool_free(cs->req, cc->req_pool);
+ }
bioset_free(cc->bs);
mempool_destroy(cc->page_pool);
@@ -1236,9 +1400,11 @@ static void crypt_dtr(struct dm_target *ti)
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);
+ crypt_dtr_cpus(cc);
dm_put_device(ti, cc->dev);
+ free_percpu(cc->cpu);
+
/* Must zero key material before freeing */
kzfree(cc);
}
@@ -1428,6 +1594,10 @@ static void __exit dm_crypt_exit(void)
{
dm_unregister_target(&crypt_target);
kmem_cache_destroy(_crypt_io_pool);
+ if (crypt_workqueue)
+ destroy_workqueue(crypt_workqueue);
+ if (io_workqueue)
+ destroy_workqueue(io_workqueue);
}
module_init(dm_crypt_init);