libfec: remove verity validation cache
Caching block validation results increases libfec memory usage and
does not provide comparable benefits in normal use cases, which do
not involve re-reading the same blocks.
Change-Id: I71ac47a7059b350b16e32207932004f3f147abcb
diff --git a/libfec/fec_verity.cpp b/libfec/fec_verity.cpp
index 7537530..8de25ef 100644
--- a/libfec/fec_verity.cpp
+++ b/libfec/fec_verity.cpp
@@ -136,30 +136,12 @@
}
/* computes a verity hash for FEC_BLOCKSIZE bytes from buffer `block' and
- compres it to the expected value in `expected'; if `index' has a value
- different from `VERITY_NO_CACHE', uses `f->cache' to cache the results */
-bool verity_check_block(fec_handle *f, uint64_t index, const uint8_t *expected,
+ compares it to the expected value in `expected' */
+bool verity_check_block(fec_handle *f, const uint8_t *expected,
const uint8_t *block)
{
check(f);
-
- if (index != VERITY_NO_CACHE) {
- pthread_mutex_lock(&f->mutex);
- auto cached = f->cache.find(index);
-
- if (cached != f->cache.end()) {
- verity_block_info vbi = *(cached->second);
-
- f->lru.erase(cached->second);
- f->lru.push_front(vbi);
- f->cache[index] = f->lru.begin();
-
- pthread_mutex_unlock(&f->mutex);
- return vbi.valid;
- }
-
- pthread_mutex_unlock(&f->mutex);
- }
+ check(block);
uint8_t hash[SHA256_DIGEST_LENGTH];
@@ -169,26 +151,7 @@
}
check(expected);
- bool valid = !memcmp(expected, hash, SHA256_DIGEST_LENGTH);
-
- if (index != VERITY_NO_CACHE) {
- pthread_mutex_lock(&f->mutex);
-
- verity_block_info vbi;
- vbi.index = index;
- vbi.valid = valid;
-
- if (f->lru.size() >= VERITY_CACHE_BLOCKS) {
- f->cache.erase(f->lru.rbegin()->index);
- f->lru.pop_back();
- }
-
- f->lru.push_front(vbi);
- f->cache[index] = f->lru.begin();
- pthread_mutex_unlock(&f->mutex);
- }
-
- return valid;
+ return !memcmp(expected, hash, SHA256_DIGEST_LENGTH);
}
/* reads a verity hash and the corresponding data block using error correction,
@@ -244,10 +207,10 @@
/* validate the root hash */
if (!raw_pread(f, data, FEC_BLOCKSIZE, hash_offset) ||
- !verity_check_block(f, VERITY_NO_CACHE, root, data)) {
+ !verity_check_block(f, root, data)) {
/* try to correct */
if (!ecc_read_hashes(f, 0, NULL, hash_offset, data) ||
- !verity_check_block(f, VERITY_NO_CACHE, root, data)) {
+ !verity_check_block(f, root, data)) {
error("root hash invalid");
return -1;
} else if (f->mode & O_RDWR &&
@@ -312,12 +275,12 @@
return -1;
}
- if (!verity_check_block(f, VERITY_NO_CACHE, hash, data)) {
+ if (!verity_check_block(f, hash, data)) {
/* try to correct */
if (!ecc_read_hashes(f,
hash_offset + j * SHA256_DIGEST_LENGTH, hash,
data_offset + j * FEC_BLOCKSIZE, data) ||
- !verity_check_block(f, VERITY_NO_CACHE, hash, data)) {
+ !verity_check_block(f, hash, data)) {
error("invalid hash tree: hash_offset %" PRIu64 ", "
"data_offset %" PRIu64 ", block %u",
hash_offset, data_offset, j);