CHROMIUM: verity: only requeue if necessary

include/linux/dm-bht.h

 /*
  * 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 GPLv2.
  */
 #ifndef __LINUX_DM_BHT_H
 #define __LINUX_DM_BHT_H
@@ skipping 111 matching lines @@
 /* Basic accessors for struct dm_bht */
 sector_t dm_bht_sectors(const struct dm_bht *bht);
 void dm_bht_set_entry_readahead(struct dm_bht *bht,
                                 unsigned int readahead_count);
 void dm_bht_set_read_cb(struct dm_bht *bht, dm_bht_callback read_cb);
 void dm_bht_set_write_cb(struct dm_bht *bht, dm_bht_callback write_cb);
 int dm_bht_set_root_hexdigest(struct dm_bht *bht, const u8 *hexdigest);
 int dm_bht_root_hexdigest(struct dm_bht *bht, u8 *hexdigest, int available);
 
 /* Functions for loading in data from disk for verification */
+bool dm_bht_is_populated(struct dm_bht *bht, unsigned int block_index);
 int dm_bht_populate(struct dm_bht *bht, void *read_cb_ctx,
                     unsigned int block_index);
 int dm_bht_verify_block(struct dm_bht *bht, unsigned int block_index,
                         const void *block);
 
 /* Functions for creating struct dm_bhts on disk.  A newly created dm_bht
  * should not be directly used for verification. (It should be repopulated.)
  * In addition, these functions aren't meant to be called in parallel.
  */
 int dm_bht_compute(struct dm_bht *bht, void *read_cb_ctx);
 int dm_bht_sync(struct dm_bht *bht, void *write_cb_ctx);
 int dm_bht_store_block(struct dm_bht *bht, unsigned int block_index,
                        u8 *block_data);
 int dm_bht_zeroread_callback(void *ctx, sector_t start, u8 *dst, sector_t count,
                              struct dm_bht_entry *entry);
 void dm_bht_read_completed(struct dm_bht_entry *entry, int status);
 void dm_bht_write_completed(struct dm_bht_entry *entry, int status);
 #endif  /* __LINUX_DM_BHT_H */