mm: slub: make object_map_lock a raw_spinlock_t

Sebastian Andrzej Siewior · tehcaster · commit 94ef0304e2b8 · 2021-09-04T10:16:45.000+02:00
The variable object_map is protected by object_map_lock. The lock is always
acquired in debug code and within already atomic context

Make object_map_lock a raw_spinlock_t.

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
diff --git a/mm/slub.c b/mm/slub.c
@@ -452,7 +452,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 
 #ifdef CONFIG_SLUB_DEBUG
 static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
-static DEFINE_SPINLOCK(object_map_lock);
+static DEFINE_RAW_SPINLOCK(object_map_lock);
 
 static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
 		       struct page *page)
@@ -497,7 +497,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
 {
 	VM_BUG_ON(!irqs_disabled());
 
-	spin_lock(&object_map_lock);
+	raw_spin_lock(&object_map_lock);
 
 	__fill_map(object_map, s, page);
 
@@ -507,7 +507,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
 static void put_map(unsigned long *map) __releases(&object_map_lock)
 {
 	VM_BUG_ON(map != object_map);
-	spin_unlock(&object_map_lock);
+	raw_spin_unlock(&object_map_lock);
 }
 
 static inline unsigned int size_from_object(struct kmem_cache *s)

Original file line number	Diff line number	Diff line change
`@@ -452,7 +452,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache s, struct page page,`
`452`	`452`
`453`	`453`	`#ifdef CONFIG_SLUB_DEBUG`
`454`	`454`	`static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];`
`455`		`-static DEFINE_SPINLOCK(object_map_lock);`
	`455`	`+static DEFINE_RAW_SPINLOCK(object_map_lock);`
`456`	`456`
`457`	`457`	`static void __fill_map(unsigned long obj_map, struct kmem_cache s,`
`458`	`458`	`struct page *page)`
`@@ -497,7 +497,7 @@ static unsigned long get_map(struct kmem_cache s, struct page *page)`
`497`	`497`	`{`
`498`	`498`	`VM_BUG_ON(!irqs_disabled());`
`499`	`499`
`500`		`- spin_lock(&object_map_lock);`
	`500`	`+ raw_spin_lock(&object_map_lock);`
`501`	`501`
`502`	`502`	`__fill_map(object_map, s, page);`
`503`	`503`
`@@ -507,7 +507,7 @@ static unsigned long get_map(struct kmem_cache s, struct page *page)`
`507`	`507`	`static void put_map(unsigned long *map) __releases(&object_map_lock)`
`508`	`508`	`{`
`509`	`509`	`VM_BUG_ON(map != object_map);`
`510`		`- spin_unlock(&object_map_lock);`
	`510`	`+ raw_spin_unlock(&object_map_lock);`
`511`	`511`	`}`
`512`	`512`
`513`	`513`	`static inline unsigned int size_from_object(struct kmem_cache *s)`