diff options
| -rw-r--r-- | mm/slab.c | 40 |
1 files changed, 21 insertions, 19 deletions
diff --git a/mm/slab.c b/mm/slab.c index ff60a94142f..3318252f657 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -730,7 +730,10 @@ static inline void init_lock_keys(void) } #endif -/* Guard access to the cache-chain. */ +/* + * 1. Guard access to the cache-chain. + * 2. Protect sanity of cpu_online_map against cpu hotplug events + */ static DEFINE_MUTEX(cache_chain_mutex); static struct list_head cache_chain; @@ -1230,12 +1233,18 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, kfree(shared); free_alien_cache(alien); } - mutex_unlock(&cache_chain_mutex); break; case CPU_ONLINE: + mutex_unlock(&cache_chain_mutex); start_cpu_timer(cpu); break; #ifdef CONFIG_HOTPLUG_CPU + case CPU_DOWN_PREPARE: + mutex_lock(&cache_chain_mutex); + break; + case CPU_DOWN_FAILED: + mutex_unlock(&cache_chain_mutex); + break; case CPU_DEAD: /* * Even if all the cpus of a node are down, we don't free the @@ -1246,8 +1255,8 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb, * gets destroyed at kmem_cache_destroy(). */ /* fall thru */ +#endif case CPU_UP_CANCELED: - mutex_lock(&cache_chain_mutex); list_for_each_entry(cachep, &cache_chain, next) { struct array_cache *nc; struct array_cache *shared; @@ -1308,11 +1317,9 @@ free_array_cache: } mutex_unlock(&cache_chain_mutex); break; -#endif } return NOTIFY_OK; bad: - mutex_unlock(&cache_chain_mutex); return NOTIFY_BAD; } @@ -2098,11 +2105,9 @@ kmem_cache_create (const char *name, size_t size, size_t align, } /* - * Prevent CPUs from coming and going. - * lock_cpu_hotplug() nests outside cache_chain_mutex + * We use cache_chain_mutex to ensure a consistent view of + * cpu_online_map as well. Please see cpuup_callback */ - lock_cpu_hotplug(); - mutex_lock(&cache_chain_mutex); list_for_each_entry(pc, &cache_chain, next) { @@ -2325,7 +2330,6 @@ oops: panic("kmem_cache_create(): failed to create slab `%s'\n", name); mutex_unlock(&cache_chain_mutex); - unlock_cpu_hotplug(); return cachep; } EXPORT_SYMBOL(kmem_cache_create); @@ -2443,6 +2447,7 @@ out: return nr_freed; } +/* Called with cache_chain_mutex held to protect against cpu hotplug */ static int __cache_shrink(struct kmem_cache *cachep) { int ret = 0, i = 0; @@ -2473,9 +2478,13 @@ static int __cache_shrink(struct kmem_cache *cachep) */ int kmem_cache_shrink(struct kmem_cache *cachep) { + int ret; BUG_ON(!cachep || in_interrupt()); - return __cache_shrink(cachep); + mutex_lock(&cache_chain_mutex); + ret = __cache_shrink(cachep); + mutex_unlock(&cache_chain_mutex); + return ret; } EXPORT_SYMBOL(kmem_cache_shrink); @@ -2499,23 +2508,16 @@ void kmem_cache_destroy(struct kmem_cache *cachep) { BUG_ON(!cachep || in_interrupt()); - /* Don't let CPUs to come and go */ - lock_cpu_hotplug(); - /* Find the cache in the chain of caches. */ mutex_lock(&cache_chain_mutex); /* * the chain is never empty, cache_cache is never destroyed */ list_del(&cachep->next); - mutex_unlock(&cache_chain_mutex); - if (__cache_shrink(cachep)) { slab_error(cachep, "Can't free all objects"); - mutex_lock(&cache_chain_mutex); list_add(&cachep->next, &cache_chain); mutex_unlock(&cache_chain_mutex); - unlock_cpu_hotplug(); return; } @@ -2523,7 +2525,7 @@ void kmem_cache_destroy(struct kmem_cache *cachep) synchronize_rcu(); __kmem_cache_destroy(cachep); - unlock_cpu_hotplug(); + mutex_unlock(&cache_chain_mutex); } EXPORT_SYMBOL(kmem_cache_destroy); |