[PATCH v2] slub: clarify kmem_cache_refill_sheaf() comments

[Hao Li <hao.li@linux.dev>]

In the in-place refill case, some objects may already have been added
before the function returns -ENOMEM.
Clarify this behavior and polish the rest of the comment for readability.

Signed-off-by: Hao Li <hao.li@linux.dev>
---
Thanks Harry for suggestions on v1!
---
 mm/slub.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 4927407c9699..a45eb1bd2ce5 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5120,12 +5120,15 @@ void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
 }
 
 /*
- * refill a sheaf previously returned by kmem_cache_prefill_sheaf to at least
- * the given size
+ * Refill a sheaf previously returned by kmem_cache_prefill_sheaf to at least
+ * the given size.
  *
- * the sheaf might be replaced by a new one when requesting more than
- * s->sheaf_capacity objects if such replacement is necessary, but the refill
- * fails (returning -ENOMEM), the existing sheaf is left intact
+ * Return: 0 on success. The sheaf will contain at least @size objects.
+ * The sheaf might be replaced with a new one if more than sheaf->capacity
+ * objects are requested.
+ *
+ * Return: -ENOMEM on failure. The refill might partially fill the existing
+ * sheaf or leave it unchanged, but it will not replace the existing sheaf.
  *
  * In practice we always refill to full sheaf's capacity.
  */
-- 
2.50.1