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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-01-18 11:53:44 +0100
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-18 20:42:36 +0200
commit5f0d5a3ae7cff0d7fa943c199c3a2e44f23e1fac (patch)
treeb7ba2116923723e193dfe7c633ec10056c6b1b53 /mm/rmap.c
parentLinux 4.11-rc2 (diff)
downloadlinux-5f0d5a3ae7cff0d7fa943c199c3a2e44f23e1fac.tar.xz
linux-5f0d5a3ae7cff0d7fa943c199c3a2e44f23e1fac.zip
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/rmap.c')
-rw-r--r--mm/rmap.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 49ed681ccc7b..8ffd59df8a3f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -430,7 +430,7 @@ static void anon_vma_ctor(void *data)
void __init anon_vma_init(void)
{
anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma),
- 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC|SLAB_ACCOUNT,
+ 0, SLAB_TYPESAFE_BY_RCU|SLAB_PANIC|SLAB_ACCOUNT,
anon_vma_ctor);
anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain,
SLAB_PANIC|SLAB_ACCOUNT);
@@ -481,7 +481,7 @@ struct anon_vma *page_get_anon_vma(struct page *page)
* If this page is still mapped, then its anon_vma cannot have been
* freed. But if it has been unmapped, we have no security against the
* anon_vma structure being freed and reused (for another anon_vma:
- * SLAB_DESTROY_BY_RCU guarantees that - so the atomic_inc_not_zero()
+ * SLAB_TYPESAFE_BY_RCU guarantees that - so the atomic_inc_not_zero()
* above cannot corrupt).
*/
if (!page_mapped(page)) {