@@ -352,15 +352,14 @@ void bch_btree_keys_init(struct btree_keys *b, const struct btree_keys_ops *ops,
b->nsets = 0;
b->last_set_unwritten = 0;
- /* XXX: shouldn't be needed */
- for (i = 0; i < MAX_BSETS; i++)
- b->set[i].size = 0;
/*
- * Second loop starts at 1 because b->keys[0]->data is the memory we
- * allocated
+ * struct btree_keys in embedded in struct btree, and struct
+ * bset_tree is embedded into struct btree_keys. They are all
+ * initialized as 0 by kzalloc() in mca_bucket_alloc(), and
+ * b->set[0].data is allocated in bch_btree_keys_alloc(), so we
+ * don't have to initiate b->set[].size and b->set[].data here
+ * any more.
*/
- for (i = 1; i < MAX_BSETS; i++)
- b->set[i].data = NULL;
}
EXPORT_SYMBOL(bch_btree_keys_init);
@@ -600,6 +600,10 @@ static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
static struct btree *mca_bucket_alloc(struct cache_set *c,
struct bkey *k, gfp_t gfp)
{
+ /*
+ * kzalloc() is necessary here for initialization,
+ * see code comments in bch_btree_keys_init().
+ */
struct btree *b = kzalloc(sizeof(struct btree), gfp);
if (!b)
return NULL;
Function bch_btree_keys_init() initializes b->set[].size and b->set[].data to zero. As the code comments indicates, these code indeed is unncessary, because both struct btree_keys and struct bset_tree are nested embedded into struct btree, when struct btree is filled with 0 bits by kzalloc() in mca_bucket_alloc(), b->set[].size and b->set[].data are initialized to 0 (a.k.a NULL) already. This patch removes the redundant code, and add comments in bch_btree_keys_init() and mca_bucket_alloc() to explain why it's safe. Signed-off-by: Coly Li <colyli@suse.de> --- drivers/md/bcache/bset.c | 13 ++++++------- drivers/md/bcache/btree.c | 4 ++++ 2 files changed, 10 insertions(+), 7 deletions(-)