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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-01-18 02:53:44 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-18 11:42:36 -0700
commit5f0d5a3ae7cff0d7fa943c199c3a2e44f23e1fac (patch)
treeb7ba2116923723e193dfe7c633ec10056c6b1b53 /mm/slub.c
parent4495c08e84729385774601b5146d51d9e5849f81 (diff)
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mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU
A group of Linux kernel hackers reported chasing a bug that resulted from their assumption that SLAB_DESTROY_BY_RCU provided an existence guarantee, that is, that no block from such a slab would be reallocated during an RCU read-side critical section. Of course, that is not the case. Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire slab of blocks. However, there is a phrase for this, namely "type safety". This commit therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order to avoid future instances of this sort of confusion. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <linux-mm@kvack.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> [ paulmck: Add comments mentioning the old name, as requested by Eric Dumazet, in order to help people familiar with the old name find the new one. ] Acked-by: David Rientjes <rientjes@google.com>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 7f4bc7027ed5..57e5156f02be 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1687,7 +1687,7 @@ static void rcu_free_slab(struct rcu_head *h)
static void free_slab(struct kmem_cache *s, struct page *page)
{
- if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
+ if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
struct rcu_head *head;
if (need_reserve_slab_rcu) {
@@ -2963,7 +2963,7 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
* slab_free_freelist_hook() could have put the items into quarantine.
* If so, no need to free them.
*/
- if (s->flags & SLAB_KASAN && !(s->flags & SLAB_DESTROY_BY_RCU))
+ if (s->flags & SLAB_KASAN && !(s->flags & SLAB_TYPESAFE_BY_RCU))
return;
do_slab_free(s, page, head, tail, cnt, addr);
}
@@ -3433,7 +3433,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
* the slab may touch the object after free or before allocation
* then we should never poison the object itself.
*/
- if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
+ if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
!s->ctor)
s->flags |= __OBJECT_POISON;
else
@@ -3455,7 +3455,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
*/
s->inuse = size;
- if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
+ if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
s->ctor)) {
/*
* Relocate free pointer after the object if it is not
@@ -3537,7 +3537,7 @@ static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
s->reserved = 0;
- if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
+ if (need_reserve_slab_rcu && (s->flags & SLAB_TYPESAFE_BY_RCU))
s->reserved = sizeof(struct rcu_head);
if (!calculate_sizes(s, -1))
@@ -5042,7 +5042,7 @@ SLAB_ATTR_RO(cache_dma);
static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
{
- return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
+ return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
}
SLAB_ATTR_RO(destroy_by_rcu);