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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/slab.h
parent4495c08e84729385774601b5146d51d9e5849f81 (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/slab.h')
-rw-r--r--mm/slab.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/slab.h b/mm/slab.h
index 65e7c3fcac72..9cfcf099709c 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -126,7 +126,7 @@ static inline unsigned long kmem_cache_flags(unsigned long object_size,
/* Legal flag mask for kmem_cache_create(), for various configurations */
#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
- SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
+ SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
#if defined(CONFIG_DEBUG_SLAB)
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
@@ -415,7 +415,7 @@ static inline size_t slab_ksize(const struct kmem_cache *s)
* back there or track user information then we can
* only use the space before that information.
*/
- if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
+ if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
return s->inuse;
/*
* Else we can use all the padding etc for the allocation