dm crypt: add async request mempool

dm-crypt: Use crypto ablkcipher interface

Introduce mempool for async crypto requests.

cc->req is used mainly during synchronous operations
(to prevent allocation and deallocation of the same object).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 43 insertions, 2 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 2da9b9536afb..79316580c780 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -80,10 +80,11 @@ struct crypt_config {
         sector_t start;
 
         /*
-         * pool for per bio private data and
-         * for encryption buffer pages
+         * pool for per bio private data, crypto requests and
+         * encryption requeusts/buffer pages
          */
         mempool_t *io_pool;
+        mempool_t *req_pool;
         mempool_t *page_pool;
         struct bio_set *bs;
 
@@ -101,6 +102,22 @@ struct crypt_config {
         sector_t iv_offset;
         unsigned int iv_size;
 
+        /*
+         * Layout of each crypto request:
+         *
+         *   struct ablkcipher_request
+         *      context
+         *      padding
+         *   struct dm_crypt_request
+         *      padding
+         *   IV
+         *
+         * The padding is added so that dm_crypt_request and the IV are
+         * correctly aligned.
+         */
+        unsigned int dmreq_start;
+        struct ablkcipher_request *req;
+
         char cipher[CRYPTO_MAX_ALG_NAME];
         char chainmode[CRYPTO_MAX_ALG_NAME];
         struct crypto_blkcipher *tfm;
@@ -377,6 +394,13 @@ static int crypt_convert_block(struct crypt_config *cc,
                                          ctx->sector);
 }
 
+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);
+}
+
 /*
  * Encrypt / decrypt data from one bio to another one (can be the same one)
  */
@@ -882,6 +906,17 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 goto bad_slab_pool;
         }
 
+        cc->dmreq_start = sizeof(struct ablkcipher_request);
+        cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
+
+        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;
+        }
+        cc->req = NULL;
+
         cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
         if (!cc->page_pool) {
                 ti->error = "Cannot allocate page mempool";
@@ -955,6 +990,8 @@ bad_device:
 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)
@@ -975,8 +1012,12 @@ static void crypt_dtr(struct dm_target *ti)
         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);