From 2bce64858442149784f6c8803c9095a8556320a2 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Mon, 19 Jul 2010 11:39:11 -0500 Subject: [PATCH] slub: Allow removal of slab caches during boot Serialize kmem_cache_create and kmem_cache_destroy using the slub_lock. Only possible after the use of the slub_lock during dynamic dma creation has been removed. Then make sure that the setup of the slab sysfs entries does not race with kmem_cache_create and kmem_cache destroy. If a slab cache is removed before we have setup sysfs then simply skip over the sysfs handling. Cc: Benjamin Herrenschmidt Cc: Roland Dreier Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- mm/slub.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index f0f403693bd9..fb6518efe1ed 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2491,7 +2491,6 @@ void kmem_cache_destroy(struct kmem_cache *s) s->refcount--; if (!s->refcount) { list_del(&s->list); - up_write(&slub_lock); if (kmem_cache_close(s)) { printk(KERN_ERR "SLUB %s: %s called for cache that " "still has objects.\n", s->name, __func__); @@ -2500,8 +2499,8 @@ void kmem_cache_destroy(struct kmem_cache *s) if (s->flags & SLAB_DESTROY_BY_RCU) rcu_barrier(); sysfs_slab_remove(s); - } else - up_write(&slub_lock); + } + up_write(&slub_lock); } EXPORT_SYMBOL(kmem_cache_destroy); @@ -3227,14 +3226,12 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, */ s->objsize = max(s->objsize, (int)size); s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); - up_write(&slub_lock); if (sysfs_slab_alias(s, name)) { - down_write(&slub_lock); s->refcount--; - up_write(&slub_lock); goto err; } + up_write(&slub_lock); return s; } @@ -3243,14 +3240,12 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, if (kmem_cache_open(s, GFP_KERNEL, name, size, align, flags, ctor)) { list_add(&s->list, &slab_caches); - up_write(&slub_lock); if (sysfs_slab_add(s)) { - down_write(&slub_lock); list_del(&s->list); - up_write(&slub_lock); kfree(s); goto err; } + up_write(&slub_lock); return s; } kfree(s); @@ -4498,6 +4493,13 @@ static int sysfs_slab_add(struct kmem_cache *s) static void sysfs_slab_remove(struct kmem_cache *s) { + if (slab_state < SYSFS) + /* + * Sysfs has not been setup yet so no need to remove the + * cache from sysfs. + */ + return; + kobject_uevent(&s->kobj, KOBJ_REMOVE); kobject_del(&s->kobj); kobject_put(&s->kobj); @@ -4543,8 +4545,11 @@ static int __init slab_sysfs_init(void) struct kmem_cache *s; int err; + down_write(&slub_lock); + slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj); if (!slab_kset) { + up_write(&slub_lock); printk(KERN_ERR "Cannot register slab subsystem.\n"); return -ENOSYS; } @@ -4569,6 +4574,7 @@ static int __init slab_sysfs_init(void) kfree(al); } + up_write(&slub_lock); resiliency_test(); return 0; }