bcachefs: Add some unlikely() annotations

Add a few easy unlikely() optimizations. These are mainly worthwhile
because the compiler will (usually) put the branch-not-taken path at the
end of the function, meaning better icache utilization.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

2 files changed, 11 insertions, 9 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 727e505730cc..742391e9ba17 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -540,15 +540,17 @@ bch2_trans_start_alloc_update(struct btree_trans *trans, struct btree_iter *iter
 			     BTREE_ITER_INTENT);
 	k = bch2_btree_iter_peek_slot(iter);
 	ret = bkey_err(k);
-	if (ret) {
-		bch2_trans_iter_exit(trans, iter);
-		return ERR_PTR(ret);
-	}
+	if (unlikely(ret))
+		goto err;
 
 	a = bch2_alloc_to_v4_mut_inlined(trans, k);
-	if (IS_ERR(a))
-		bch2_trans_iter_exit(trans, iter);
+	ret = PTR_ERR_OR_ZERO(a);
+	if (unlikely(ret))
+		goto err;
 	return a;
+err:
+	bch2_trans_iter_exit(trans, iter);
+	return ERR_PTR(ret);
 }
 
 int bch2_alloc_read(struct bch_fs *c)
diff --git a/fs/bcachefs/bkey.c b/fs/bcachefs/bkey.c
index 0ee38d25c1d0..6ad4b818f9a5 100644
--- a/fs/bcachefs/bkey.c
+++ b/fs/bcachefs/bkey.c
@@ -497,18 +497,18 @@ enum bkey_pack_pos_ret bch2_bkey_pack_pos_lossy(struct bkey_packed *out,
 		     le64_to_cpu(f->field_offset[BKEY_FIELD_INODE])))
 		return BKEY_PACK_POS_FAIL;
 
-	if (!set_inc_field_lossy(&state, BKEY_FIELD_INODE, in.inode)) {
+	if (unlikely(!set_inc_field_lossy(&state, BKEY_FIELD_INODE, in.inode))) {
 		in.offset	= KEY_OFFSET_MAX;
 		in.snapshot	= KEY_SNAPSHOT_MAX;
 		exact = false;
 	}
 
-	if (!set_inc_field_lossy(&state, BKEY_FIELD_OFFSET, in.offset)) {
+	if (unlikely(!set_inc_field_lossy(&state, BKEY_FIELD_OFFSET, in.offset))) {
 		in.snapshot	= KEY_SNAPSHOT_MAX;
 		exact = false;
 	}
 
-	if (!set_inc_field_lossy(&state, BKEY_FIELD_SNAPSHOT, in.snapshot))
+	if (unlikely(!set_inc_field_lossy(&state, BKEY_FIELD_SNAPSHOT, in.snapshot)))
 		exact = false;
 
 	pack_state_finish(&state, out);