mm/slub.c: remove validation on cpu_slab in __flush_cpu_slab()

cpu_slab is a per cpu variable which is allocated in all or none.  If a
cpu_slab failed to be allocated, the slub is not usable.

We could use cpu_slab without validation in __flush_cpu_slab().

Link: http://lkml.kernel.org/r/20181103141218.22844-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/slub.c b/mm/slub.c
index 08740c3..3fd791c 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2317,12 +2317,10 @@ static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
 {
        struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 
-       if (likely(c)) {
-               if (c->page)
-                       flush_slab(s, c);
+       if (c->page)
+               flush_slab(s, c);
 
-               unfreeze_partials(s, c);
-       }
+       unfreeze_partials(s, c);
 }
 
 static void flush_cpu_slab(void *d)