[PATCH -next v2] mm: zswap: update comment for struct zswap_entry

[Xiu Jianfeng <xiujianfeng@huaweicloud.com>]

From: Xiu Jianfeng <xiujianfeng@huawei.com>

Since commit 0bb488498c98 ("mm: zswap: remove zswap_header"), the
'offset' has been replaced by swpentry, update the comment for it,
and also add comment for 'objcg'.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>

---
v2: reword the comment
---
 mm/zswap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index 5b56d38e7339..1e17f11a7896 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -182,7 +182,7 @@ struct zswap_pool {
  * page within zswap.
  *
  * rbnode - links the entry into red-black tree for the appropriate swap type
- * offset - the swap offset for the entry.  Index into the red-black tree.
+ * swpentry - associated swap entry, the offset indexes into the red-black tree
  * refcount - the number of outstanding reference to the entry. This is needed
  *            to protect against premature freeing of the entry by code
  *            concurrent calls to load, invalidate, and writeback.  The lock
@@ -195,6 +195,7 @@ struct zswap_pool {
  * pool - the zswap_pool the entry's data is in
  * handle - zpool allocation handle that stores the compressed page data
  * value - value of the same-value filled pages which have same content
+ * objcg - the obj_cgroup that the compressed memory is charged to
  * lru - handle to the pool's lru used to evict pages.
  */
 struct zswap_entry {
-- 
2.34.1