[PATCH v3 04/24] mm/balloon_compaction: improve comments for WARN_ON_ONCE(!b_dev_info)

[David Hildenbrand (Red Hat)]

Let's clarify a bit by extending the comments.

Signed-off-by: David Hildenbrand (Red Hat) <da...@kernel.org>
---
 mm/balloon_compaction.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 03c5dbabb1565..85eea88cea083 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -222,7 +222,11 @@ static void balloon_page_putback(struct page *page)
        struct balloon_dev_info *b_dev_info = balloon_page_device(page);
        unsigned long flags;
 
-       /* Isolated balloon pages cannot get deflated. */
+       /*
+        * When we isolated the page, the page was still inflated in a balloon
+        * device. As isolated balloon pages cannot get deflated, we still have
+        * a balloon device here.
+        */
        if (WARN_ON_ONCE(!b_dev_info))
                return;
 
@@ -241,7 +245,11 @@ static int balloon_page_migrate(struct page *newpage, 
struct page *page,
        VM_BUG_ON_PAGE(!PageLocked(page), page);
        VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
 
-       /* Isolated balloon pages cannot get deflated. */
+       /*
+        * When we isolated the page, the page was still inflated in a balloon
+        * device. As isolated balloon pages cannot get deflated, we still have
+        * a balloon device here.
+        */
        if (WARN_ON_ONCE(!balloon))
                return -EAGAIN;
 
-- 
2.52.0