diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-01-18 02:53:44 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 11:42:36 -0700 |
| commit | 5f0d5a3ae7cff0d7fa943c199c3a2e44f23e1fac (patch) | |
| tree | b7ba2116923723e193dfe7c633ec10056c6b1b53 /mm/slub.c | |
| parent | 4495c08e84729385774601b5146d51d9e5849f81 (diff) | |
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.c | 12 |
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); |