CHROMIUM: verity: remove compare_hash layer

drivers/md/dm-bht.c

  /*
  * Copyright (C) 2010 The Chromium OS Authors <chromium-os-dev@chromium.org>
  *
  * Device-Mapper block hash tree interface.
  * See Documentation/device-mapper/dm-bht.txt for details.
  *
  * This file is released under the GPL.
  */
 
 #include <asm/atomic.h>
@@ skipping 505 matching lines @@
 
         return state;
 
 nomem:
         DMCRIT("failed to allocate memory for entry->nodes from pool");
         return -ENOMEM;
 
 
 }
 
-static int dm_bht_compare_hash(struct dm_bht *bht, u8 *known, u8 *computed)
-{
-        return memcmp(known, computed, bht->digest_size);
-}
-
 /* dm_bht_verify_path
  * Verifies the path. Returns 0 on ok.
  */
 static int dm_bht_verify_path(struct dm_bht *bht, unsigned int block_index,
                               struct page *pg, unsigned int offset)
 {
         unsigned int depth = bht->depth;
         u8 digest[DM_BHT_MAX_DIGEST_SIZE];
         struct dm_bht_entry *entry;
         u8 *node;
         int state;
 
         do {
                 /* Need to check that the hash of the current block is accurate
                  * in its parent.
                  */
                 entry = dm_bht_get_entry(bht, depth - 1, block_index);
                 state = atomic_read(&entry->state);
                 /* This call is only safe if all nodes along the path
                  * are already populated (i.e. READY) via dm_bht_populate.
                  */
                 BUG_ON(state < DM_BHT_ENTRY_READY);
                 node = dm_bht_get_node(bht, entry, depth, block_index);
 
                 if (dm_bht_compute_hash(bht, pg, offset, digest) ||
-                    dm_bht_compare_hash(bht, digest, node))
+                    memcmp(digest, node, bht->digest_size))
                         goto mismatch;
 
                 /* Keep the containing block of hashes to be verified in the
                  * next pass.
                  */
                 pg = virt_to_page(entry->nodes);
                 offset = 0;
         } while (--depth > 0 && state != DM_BHT_ENTRY_VERIFIED);
 
         if (depth == 0 && state != DM_BHT_ENTRY_VERIFIED) {
                 if (dm_bht_compute_hash(bht, pg, offset, digest) ||
-                    dm_bht_compare_hash(bht, digest, bht->root_digest))
+                    memcmp(digest, bht->root_digest, bht->digest_size))
                         goto mismatch;
                 atomic_set(&entry->state, DM_BHT_ENTRY_VERIFIED);
         }
 
         /* Mark path to leaf as verified. */
         for (depth++; depth < bht->depth; depth++) {
                 entry = dm_bht_get_entry(bht, depth, block_index);
                 /* At this point, entry can only be in VERIFIED or READY state.
                  * So it is safe to use atomic_set instead of atomic_cmpxchg.
                  */
@@ skipping 437 matching lines @@
         if (!bht->root_digest) {
                 DMERR("no root digest exists to export");
                 if (available > 0)
                         *hexdigest = 0;
                 return -1;
         }
         dm_bht_bin_to_hex(bht->root_digest, hexdigest, bht->digest_size);
         return 0;
 }
 EXPORT_SYMBOL(dm_bht_root_hexdigest);