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slub: Allow removal of slab caches during boot

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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 <benh@kernel.crashing.org>
Cc: Roland Dreier <rdreier@cisco.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This commit is contained in:
Christoph Lameter 2010-07-19 11:39:11 -05:00 committed by Pekka Enberg
parent e438444de8
commit 2bce648584
1 changed files with 15 additions and 9 deletions
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24
mm/slub.c
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@ -2491,7 +2491,6 @@ void kmem_cache_destroy(struct kmem_cache *s)
s->refcount--; s->refcount--;
if (!s->refcount) { if (!s->refcount) {
list_del(&s->list); list_del(&s->list);
up_write(&slub_lock);
if (kmem_cache_close(s)) { if (kmem_cache_close(s)) {
printk(KERN_ERR "SLUB %s: %s called for cache that " printk(KERN_ERR "SLUB %s: %s called for cache that "
"still has objects.\n", s->name, __func__); "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) if (s->flags & SLAB_DESTROY_BY_RCU)
rcu_barrier(); rcu_barrier();
sysfs_slab_remove(s); sysfs_slab_remove(s);
} else }
up_write(&slub_lock); up_write(&slub_lock);
} }
EXPORT_SYMBOL(kmem_cache_destroy); 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->objsize = max(s->objsize, (int)size);
s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
up_write(&slub_lock);
if (sysfs_slab_alias(s, name)) { if (sysfs_slab_alias(s, name)) {
down_write(&slub_lock);
s->refcount--; s->refcount--;
up_write(&slub_lock);
goto err; goto err;
} }
up_write(&slub_lock);
return s; 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, if (kmem_cache_open(s, GFP_KERNEL, name,
size, align, flags, ctor)) { size, align, flags, ctor)) {
list_add(&s->list, &slab_caches); list_add(&s->list, &slab_caches);
up_write(&slub_lock);
if (sysfs_slab_add(s)) { if (sysfs_slab_add(s)) {
down_write(&slub_lock);
list_del(&s->list); list_del(&s->list);
up_write(&slub_lock);
kfree(s); kfree(s);
goto err; goto err;
} }
up_write(&slub_lock);
return s; return s;
} }
kfree(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) 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_uevent(&s->kobj, KOBJ_REMOVE);
kobject_del(&s->kobj); kobject_del(&s->kobj);
kobject_put(&s->kobj); kobject_put(&s->kobj);
@ -4543,8 +4545,11 @@ static int __init slab_sysfs_init(void)
struct kmem_cache *s; struct kmem_cache *s;
int err; int err;
down_write(&slub_lock);
slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj); slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
if (!slab_kset) { if (!slab_kset) {
up_write(&slub_lock);
printk(KERN_ERR "Cannot register slab subsystem.\n"); printk(KERN_ERR "Cannot register slab subsystem.\n");
return -ENOSYS; return -ENOSYS;
} }
@ -4569,6 +4574,7 @@ static int __init slab_sysfs_init(void)
kfree(al); kfree(al);
} }
up_write(&slub_lock);
resiliency_test(); resiliency_test();
return 0; return 0;
} }