Revert "verity: pull up maybe_read_entry"
This reverts commit 1b11b6793110da756e4c153b860f1870c7687072
The commit seems to cause unit test failures in a VM
Change-Id: I4739a7bdca2b2228cc7c5f8eecf407e56fc7e62a
Reviewed-on: http://gerrit.chromium.org/gerrit/4282
Tested-by: Chris Masone <cmasone@chromium.org>
Tested-by: Will Drewry <wad@chromium.org>
Reviewed-by: Will Drewry <wad@chromium.org>
diff --git a/dm-bht.c b/dm-bht.c
index a9968c0..7467455 100644
--- a/dm-bht.c
+++ b/dm-bht.c
@@ -459,6 +459,70 @@
}
EXPORT_SYMBOL(dm_bht_write_completed);
+/* dm_bht_maybe_read_entry
+ * Attempts to atomically acquire an entry, allocate any needed
+ * memory, and issues the I/O callback to load the hash from disk.
+ * Return value is negative on error. When positive, it is the state
+ * value.
+ */
+static int dm_bht_maybe_read_entry(struct dm_bht *bht, void *ctx,
+ unsigned int depth, unsigned int index)
+{
+ struct dm_bht_level *level = &bht->levels[depth];
+ struct dm_bht_entry *entry = &level->entries[index];
+ sector_t current_sector = level->sector + to_sector(index * PAGE_SIZE);
+ struct page *node_page;
+ int state;
+
+ BUG_ON(depth >= bht->depth);
+
+ /* XXX: hardcoding PAGE_SIZE means that a perfectly valid image
+ * on one system may not work on a different kernel.
+ * TODO(wad) abstract PAGE_SIZE with a bht->entry_size or
+ * at least a define and ensure bht->entry_size is
+ * sector aligned at least.
+ */
+
+ /* If the entry's state is UNALLOCATED, then we'll claim it
+ * for allocation and loading.
+ */
+ state = atomic_cmpxchg(&entry->state,
+ DM_BHT_ENTRY_UNALLOCATED,
+ DM_BHT_ENTRY_PENDING);
+ DMDEBUG("dm_bht_maybe_read_entry(d=%u,ei=%u): ei=%lu, state=%d",
+ depth, index, (unsigned long)(entry - level->entries), state);
+
+ if (state != DM_BHT_ENTRY_UNALLOCATED)
+ goto out;
+
+ state = DM_BHT_ENTRY_REQUESTED;
+
+ /* Current entry is claimed for allocation and loading */
+ node_page = (struct page *) mempool_alloc(bht->entry_pool, GFP_NOIO);
+ if (!node_page)
+ goto nomem;
+ /* dm-bht guarantees page-aligned memory for callbacks. */
+ entry->nodes = page_address(node_page);
+
+ /* TODO(wad) error check callback here too */
+ DMDEBUG("dm_bht_maybe_read_entry(d=%u,ei=%u): reading %lu",
+ depth, index, (unsigned long)(entry - level->entries));
+ bht->read_cb(ctx, current_sector, entry->nodes,
+ to_sector(PAGE_SIZE), entry);
+
+out:
+ if (state <= DM_BHT_ENTRY_ERROR)
+ DMCRIT("entry %u is in an error state", index);
+
+ return state;
+
+nomem:
+ DMCRIT("failed to allocate memory for entry->nodes from pool");
+ return -ENOMEM;
+
+
+}
+
/* dm_bht_verify_path
* Verifies the path. Returns 0 on ok.
*/
@@ -652,18 +716,13 @@
for (i = 0; i < level->count; i++, entry++) {
unsigned int count = bht->node_count;
- struct page *pg;
- pg = (struct page *) mempool_alloc(bht->entry_pool,
- GFP_NOIO);
- if (!pg) {
+ r = dm_bht_maybe_read_entry(bht, read_cb_ctx, depth, i);
+ if (r < 0) {
DMCRIT("an error occurred while reading entry");
goto out;
}
- entry->nodes = page_address(pg);
- atomic_set(&entry->state, DM_BHT_ENTRY_READY);
-
if (i == (level->count - 1))
count = child_level->count % bht->node_count;
if (count == 0)
@@ -768,63 +827,38 @@
/**
* dm_bht_populate - reads entries from disk needed to verify a given block
* @bht: pointer to a dm_bht_create()d bht
- * @ctx: context used for all read_cb calls on this request
+ * @read_cb_ctx:context used for all read_cb calls on this request
* @block_index:specific block data is expected from
*
- * Returns negative value on error. Returns 0 on success.
+ * Returns negative value on error.
*/
-int dm_bht_populate(struct dm_bht *bht, void *ctx,
+int dm_bht_populate(struct dm_bht *bht, void *read_cb_ctx,
unsigned int block_index)
{
- unsigned int depth;
- int state = 0;
+ unsigned int depth, entry_index;
+ int status, populated = 0;
BUG_ON(block_index >= bht->block_count);
DMDEBUG("dm_bht_populate(%u)", block_index);
for (depth = 0; depth < bht->depth; ++depth) {
- struct dm_bht_level *level;
- struct dm_bht_entry *entry;
- unsigned int index;
- struct page *pg;
+ entry_index = dm_bht_index_at_level(bht, depth, block_index);
+ status = dm_bht_maybe_read_entry(bht, read_cb_ctx, depth,
+ entry_index);
+ if (status < 0)
+ goto read_error;
- entry = dm_bht_get_entry(bht, depth, block_index);
- state = atomic_cmpxchg(&entry->state,
- DM_BHT_ENTRY_UNALLOCATED,
- DM_BHT_ENTRY_PENDING);
-
- if (state <= DM_BHT_ENTRY_ERROR)
- goto error_state;
-
- if (state != DM_BHT_ENTRY_UNALLOCATED)
- continue;
-
- /* Current entry is claimed for allocation and loading */
- pg = (struct page *) mempool_alloc(bht->entry_pool, GFP_NOIO);
- if (!pg)
- goto nomem;
-
- /* dm-bht guarantees page-aligned memory for callbacks. */
- entry->nodes = page_address(pg);
-
- /* TODO(wad) error check callback here too */
-
- level = &bht->levels[depth];
- index = dm_bht_index_at_level(bht, depth, block_index);
- bht->read_cb(ctx, level->sector + to_sector(index * PAGE_SIZE),
- entry->nodes, to_sector(PAGE_SIZE), entry);
+ /* Accrue return code flags */
+ populated |= status;
}
- return 0;
+ return populated;
-error_state:
- DMCRIT("block %u at depth %u is in an error state", block_index, depth);
- return state;
+read_error:
+ DMCRIT("failure reading entry %u depth %u", entry_index, depth);
+ return status;
-nomem:
- DMCRIT("failed to allocate memory for entry->nodes from pool");
- return -ENOMEM;
}
EXPORT_SYMBOL(dm_bht_populate);
diff --git a/dm-bht.h b/dm-bht.h
index 44a1c02..21d5e34 100644
--- a/dm-bht.h
+++ b/dm-bht.h
@@ -25,6 +25,9 @@
#define DM_BHT_ENTRY_VERIFIED 8 /* 'nodes' has been checked against parent */
#define DM_BHT_ENTRY_READY 4 /* 'nodes' is loaded and available */
#define DM_BHT_ENTRY_PENDING 2 /* 'nodes' is being loaded */
+#define DM_BHT_ENTRY_REQUESTED 1 /* non-state response indicating entry is
+ * pending because of the current call
+ */
#define DM_BHT_ENTRY_UNALLOCATED 0 /* untouched */
#define DM_BHT_ENTRY_ERROR -1 /* entry is unsuitable for use */
#define DM_BHT_ENTRY_ERROR_IO -2 /* I/O error on load */
diff --git a/dm-bht_unittest.cc b/dm-bht_unittest.cc
index 3725009..396b446 100644
--- a/dm-bht_unittest.cc
+++ b/dm-bht_unittest.cc
@@ -140,7 +140,7 @@
EXPECT_GE(dm_bht_populate(bht_.get(),
reinterpret_cast<void *>(this),
blocks),
- DM_BHT_ENTRY_PENDING);
+ DM_BHT_ENTRY_REQUESTED);
// Since we're testing synchronously, a second run through should yield
// READY.
EXPECT_GE(dm_bht_populate(bht_.get(),
