[PATCH v3.10-rt] slab: make kmem_cache_node's list_lock conditionally raw

[Paul Gortmaker <paul.gortmaker@windriver.com>]

The RT patch "mm-disable-slab-on-rt.patch" unconditionally
converts kmem_cache_node's list_lock into a raw lock.  As
of mainline commit ca34956b804b7554fc4e88826773380d9d5122a8
("slab: Common definition for kmem_cache_node") the definition
is shared -- but slab.c still thinks the lock is non raw.

At the moment SLAB depends on !RT_FULL, however with the lock
being raw for !RT_FULL, we can't build the SLAB + !RT_FULL
combination because of the above.  So only convert the lock if
SLAB is not enabled.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---

[Should be squished into mm-disable-slab-on-rt.patch ]

 mm/slab.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/slab.h b/mm/slab.h
index 2e6c8b7..fc3c097 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -247,7 +247,11 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
  * The slab lists for all objects.
  */
 struct kmem_cache_node {
+#ifdef CONFIG_SLAB
+	spinlock_t list_lock;
+#else
 	raw_spinlock_t list_lock;
+#endif
 
 #ifdef CONFIG_SLAB
 	struct list_head slabs_partial;	/* partial list first, better asm code */
-- 
1.8.1.2