linux-kernel - [PATCH v3 28/35] mm, slab: make flush_slab() possible to call with irqs enabled

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: <20210729132132.19691-29-vbabka@suse.cz>
Date:   Thu, 29 Jul 2021 15:21:25 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Christoph Lameter <cl@...ux.com>,
        David Rientjes <rientjes@...gle.com>,
        Pekka Enberg <penberg@...nel.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>
Cc:     Mike Galbraith <efault@....de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Jann Horn <jannh@...gle.com>, Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH v3 28/35] mm, slab: make flush_slab() possible to call with irqs enabled

Currently flush_slab() is always called with disabled IRQs if it's needed, but
the following patches will change that, so add a parameter to control IRQ
disabling within the function, which only protects the kmem_cache_cpu
manipulation and not the call to deactivate_slab() which doesn't need it.

Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
---
 mm/slub.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index edda419ec260..9fbc5396f3e1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2477,16 +2477,28 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
 #endif	/* CONFIG_SLUB_CPU_PARTIAL */
 }
 
-static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
+static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c,
+			      bool lock)
 {
-	void *freelist = c->freelist;
-	struct page *page = c->page;
+	unsigned long flags;
+	void *freelist;
+	struct page *page;
+
+	if (lock)
+		local_irq_save(flags);
+
+	freelist = c->freelist;
+	page = c->page;
 
 	c->page = NULL;
 	c->freelist = NULL;
 	c->tid = next_tid(c->tid);
 
-	deactivate_slab(s, page, freelist);
+	if (lock)
+		local_irq_restore(flags);
+
+	if (page)
+		deactivate_slab(s, page, freelist);
 
 	stat(s, CPUSLAB_FLUSH);
 }
@@ -2496,7 +2508,7 @@ static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
 	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 
 	if (c->page)
-		flush_slab(s, c);
+		flush_slab(s, c, false);
 
 	unfreeze_partials_cpu(s, c);
 }
@@ -2512,7 +2524,7 @@ static void flush_cpu_slab(void *d)
 	struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
 
 	if (c->page)
-		flush_slab(s, c);
+		flush_slab(s, c, false);
 
 	unfreeze_partials(s);
 }
-- 
2.32.0