linux-kernel - [RFC PATCH v4 5/9] slub: Introduce freeze

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20231031140741.79387-6-chengming.zhou@linux.dev>
Date:   Tue, 31 Oct 2023 14:07:37 +0000
From:   chengming.zhou@...ux.dev
To:     vbabka@...e.cz, cl@...ux.com, penberg@...nel.org,
        willy@...radead.org
Cc:     rientjes@...gle.com, iamjoonsoo.kim@....com,
        akpm@...ux-foundation.org, roman.gushchin@...ux.dev,
        42.hyeyoo@...il.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, chengming.zhou@...ux.dev,
        Chengming Zhou <zhouchengming@...edance.com>
Subject: [RFC PATCH v4 5/9] slub: Introduce freeze_slab()

From: Chengming Zhou <zhouchengming@...edance.com>

We will have unfrozen slabs out of the node partial list later, so we
need a freeze_slab() function to freeze the partial slab and get its
freelist.

Signed-off-by: Chengming Zhou <zhouchengming@...edance.com>
Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
---
 mm/slub.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index 1880b483350e..edf567971679 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3098,6 +3098,33 @@ static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
 	return freelist;
 }
 
+/*
+ * Freeze the partial slab and return the pointer to the freelist.
+ */
+static inline void *freeze_slab(struct kmem_cache *s, struct slab *slab)
+{
+	struct slab new;
+	unsigned long counters;
+	void *freelist;
+
+	do {
+		freelist = slab->freelist;
+		counters = slab->counters;
+
+		new.counters = counters;
+		VM_BUG_ON(new.frozen);
+
+		new.inuse = slab->objects;
+		new.frozen = 1;
+
+	} while (!slab_update_freelist(s, slab,
+		freelist, counters,
+		NULL, new.counters,
+		"freeze_slab"));
+
+	return freelist;
+}
+
 /*
  * Slow path. The lockless freelist is empty or we need to perform
  * debugging duties.
-- 
2.20.1