crypto: nx - fix limits to sg lists for AES-CTR

This patch updates the nx-aes-ctr implementation to perform several
hyper calls if needed in order to always respect the length limits for
scatter/gather lists.

Two different limits are considered:

 - "ibm,max-sg-len": maximum number of bytes of each scatter/gather
   list.

 - "ibm,max-sync-cop":
    - The total number of bytes that a scatter/gather list can hold.
    - The maximum number of elements that a scatter/gather list can have.

Reviewed-by: Joy Latten <jmlatten@linux.vnet.ibm.com>
Signed-off-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 31 insertions, 19 deletions

diff --git a/drivers/crypto/nx/nx-aes-ctr.c b/drivers/crypto/nx/nx-aes-ctr.c
index 80dee8d58659..a37d009dc75c 100644
--- a/drivers/crypto/nx/nx-aes-ctr.c
+++ b/drivers/crypto/nx/nx-aes-ctr.c
@@ -89,33 +89,45 @@ static int ctr_aes_nx_crypt(struct blkcipher_desc *desc,
         struct nx_crypto_ctx *nx_ctx = crypto_blkcipher_ctx(desc->tfm);
         struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
         unsigned long irq_flags;
+        unsigned int processed = 0, to_process;
+        u32 max_sg_len;
         int rc;
 
         spin_lock_irqsave(&nx_ctx->lock, irq_flags);
 
-        if (nbytes > nx_ctx->ap->databytelen) {
-                rc = -EINVAL;
-                goto out;
-        }
+        max_sg_len = min_t(u32, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
+                           nx_ctx->ap->sglen);
 
-        rc = nx_build_sg_lists(nx_ctx, desc, dst, src, nbytes, 0,
-                               csbcpb->cpb.aes_ctr.iv);
-        if (rc)
-                goto out;
+        do {
+                to_process = min_t(u64, nbytes - processed,
+                                   nx_ctx->ap->databytelen);
+                to_process = min_t(u64, to_process,
+                                   NX_PAGE_SIZE * (max_sg_len - 1));
+                to_process = to_process & ~(AES_BLOCK_SIZE - 1);
 
-        if (!nx_ctx->op.inlen || !nx_ctx->op.outlen) {
-                rc = -EINVAL;
-                goto out;
-        }
+                rc = nx_build_sg_lists(nx_ctx, desc, dst, src, to_process,
+                                       processed, csbcpb->cpb.aes_ctr.iv);
+                if (rc)
+                        goto out;
+
+                if (!nx_ctx->op.inlen || !nx_ctx->op.outlen) {
+                        rc = -EINVAL;
+                        goto out;
+                }
+
+                rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
+                                   desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+                if (rc)
+                        goto out;
+
+                memcpy(desc->info, csbcpb->cpb.aes_cbc.cv, AES_BLOCK_SIZE);
 
-        rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
-                           desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP);
-        if (rc)
-                goto out;
+                atomic_inc(&(nx_ctx->stats->aes_ops));
+                atomic64_add(csbcpb->csb.processed_byte_count,
+                             &(nx_ctx->stats->aes_bytes));
 
-        atomic_inc(&(nx_ctx->stats->aes_ops));
-        atomic64_add(csbcpb->csb.processed_byte_count,
-                     &(nx_ctx->stats->aes_bytes));
+                processed += to_process;
+        } while (processed < nbytes);
 out:
         spin_unlock_irqrestore(&nx_ctx->lock, irq_flags);
         return rc;