verity: remove entry_readahead

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 299 matching lines @@
         }
 
         /* Setup callback stubs */
         bht->read_cb = &dm_bht_read_callback_stub;
         bht->write_cb = &dm_bht_write_callback_stub;
 
         status = dm_bht_initialize_entries(bht);
         if (status)
                 goto bad_entries_alloc;
 
-        bht->entry_readahead = 0;
         return 0;
 
 bad_entries_alloc:
         while (bht->depth-- > 0)
                 kfree(bht->levels[bht->depth].entries);
 bad_node_count:
         kfree(bht->levels);
 bad_level_alloc:
 bad_block_count:
 bad_depth:
@@ skipping 673 matching lines @@
                 read_status = dm_bht_maybe_read_entries(bht, read_cb_ctx,
                                                         depth, entry_index,
                                                         1, false);
                 if (unlikely(read_status < 0)) {
                         DMCRIT("failure occurred reading entry %u depth %u",
                                entry_index, depth);
                         return read_status;
                 }
                 /* Accrue return code flags */
                 populated |= read_status;
-
-                /* Attempt to pull in up to entry_readahead extra entries on
-                 * this I/O call iff we're doing the read right now.  This
-                 * helps optimize sequential access to the mapped drive.
-                 */
-                if (bht->entry_readahead &&
-                    (read_status & DM_BHT_ENTRY_REQUESTED)) {
-                        unsigned int readahead_count;
-                        entry_index++;
-                        readahead_count = min(bht->entry_readahead,
-                                              level->count - entry_index);
-                        /* The result is completely ignored since this call is
-                         * critical for the current request.
-                         */
-                        if (readahead_count)
-                                dm_bht_maybe_read_entries(bht, read_cb_ctx,
-                                                          depth, entry_index,
-                                                          readahead_count,
-                                                          true);
-                }
         }
 
         /* All nodes are ready. The hash for the block_index can be verified */
         return populated;
 }
 EXPORT_SYMBOL(dm_bht_populate);
 
 
 /**
  * dm_bht_verify_block - checks that all nodes in the path for @block are valid
@@ skipping 109 matching lines @@
  * @bht:        pointer to a dm_bht_create()d bht
  * @write_cb:   callback function used for all write requests by @bht
  */
 void dm_bht_set_write_cb(struct dm_bht *bht, dm_bht_callback write_cb)
 {
         bht->write_cb = write_cb;
 }
 EXPORT_SYMBOL(dm_bht_set_write_cb);
 
 /**
- * dm_bht_set_entry_readahead - set verify mode
- * @bht:        pointer to a dm_bht_create()d bht
- * @readahead_count:    number of entries to readahead from a given level
- */
-void dm_bht_set_entry_readahead(struct dm_bht *bht,
-                                unsigned int readahead_count)
-{
-        bht->entry_readahead = readahead_count;
-}
-EXPORT_SYMBOL(dm_bht_set_entry_readahead);
-
-/**
  * dm_bht_set_root_hexdigest - sets an unverified root digest hash from hex
  * @bht:        pointer to a dm_bht_create()d bht
  * @hexdigest:  array of u8s containing the new digest in binary
  * Returns non-zero on error.  hexdigest should be NUL terminated.
  */
 int dm_bht_set_root_hexdigest(struct dm_bht *bht, const u8 *hexdigest)
 {
         if (!bht->root_digest) {
                 DMCRIT("No allocation for root digest. Call dm_bht_create");
                 return -1;
@@ skipping 33 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);
-