[merged mm-stable] mm-zswap-tighten-up-entry-invalidation.patch removed from -mm tree

[merged mm-stable] mm-zswap-tighten-up-entry-invalidation.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: zswap: tighten up entry invalidation
has been removed from the -mm tree.  Its filename was
     mm-zswap-tighten-up-entry-invalidation.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: mm: zswap: tighten up entry invalidation
Date: Thu, 27 Jul 2023 12:22:24 -0400

Removing a zswap entry from the tree is tied to an explicit operation
that's supposed to drop the base reference: swap invalidation, exclusive
load, duplicate store.  Don't silently remove the entry on final put, but
instead warn if an entry is in tree without reference.

While in that diff context, convert a BUG_ON to a WARN_ON_ONCE.  No need
to crash on a refcount underflow.

Link: https://lkml.kernel.org/r/20230727162343.1415598-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zswap.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/zswap.c~mm-zswap-tighten-up-entry-invalidation
+++ a/mm/zswap.c
@@ -417,9 +417,9 @@ static void zswap_entry_put(struct zswap
 {
 	int refcount = --entry->refcount;
 
-	BUG_ON(refcount < 0);
+	WARN_ON_ONCE(refcount < 0);
 	if (refcount == 0) {
-		zswap_rb_erase(&tree->rbroot, entry);
+		WARN_ON_ONCE(!RB_EMPTY_NODE(&entry->rbnode));
 		zswap_free_entry(entry);
 	}
 }
_

Patches currently in -mm which might be from hannes@cmpxchg.org are