[PATCH 01/2] bcache: add code comments for bch_btree_node_get() and __bch_btree_node_alloc()

[PATCH 01/2] bcache: add code comments for bch_btree_node_get() and __bch_btree_node_alloc()

[Coly Li]

This patch adds code comments to bch_btree_node_get() and
__bch_btree_node_alloc() that NULL pointer will not be returned and it
is unnecessary to check NULL pointer by the callers of these routines.

Signed-off-by: Coly Li <colyli@suse.de>
---
 drivers/md/bcache/btree.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 79f1fa4a0d55..de3019972b35 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1000,6 +1000,9 @@ static struct btree *mca_alloc(struct cache_set *c, struct btree_op *op,
  *
  * The btree node will have either a read or a write lock held, depending on
  * level and op->lock.
+ *
+ * Note: Only error code or btree pointer will be returned, it is unncessary
+ *       for callers to check NULL pointer.
  */
 struct btree *bch_btree_node_get(struct cache_set *c, struct btree_op *op,
 				 struct bkey *k, int level, bool write,
@@ -1111,6 +1114,10 @@ static void btree_node_free(struct btree *b)
 	mutex_unlock(&b->c->bucket_lock);
 }
 
+/*
+ * Only error code or btree pointer will be returned, it is unncessary for
+ * callers to check NULL pointer.
+ */
 struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
 				     int level, bool wait,
 				     struct btree *parent)
-- 
2.35.3

[PATCH 2/2] bcache: avoid NULL checking to c->root in run_cache_set()

[Coly Li]

In run_cache_set() after c->root returned from bch_btree_node_get(), it
is checked by IS_ERR_OR_NULL(). Indeed it is unncessary to check NULL
because bch_btree_node_get() will not return NULL pointer to caller.

This patch replaces IS_ERR_OR_NULL() by IS_ERR() for the above reason.

Signed-off-by: Coly Li <colyli@suse.de>
---
 drivers/md/bcache/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index c7ecc7058d77..bfe1685dbae5 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2018,7 +2018,7 @@ static int run_cache_set(struct cache_set *c)
 		c->root = bch_btree_node_get(c, NULL, k,
 					     j->btree_level,
 					     true, NULL);
-		if (IS_ERR_OR_NULL(c->root))
+		if (IS_ERR(c->root))
 			goto err;
 
 		list_del_init(&c->root->list);
-- 
2.35.3