mm/slab: delete cache_alloc_debugcheck_before()

It only does a might_sleep_if(GFP_RECLAIM) check, which is already covered
by the might_alloc() in slab_pre_alloc_hook(). And all callers of
cache_alloc_debugcheck_before() call that beforehand already.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Daniel Vetter <[e-mail]>
Cc: Christoph Lameter <[e-mail]>
Cc: Pekka Enberg <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/slab.c

···
 	return ac->entry[--ac->avail];
 }
 
-static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
-						gfp_t flags)
-{
-	might_sleep_if(gfpflags_allow_blocking(flags));
-}
-
 #if DEBUG
 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 				gfp_t flags, void *objp, unsigned long caller)
···
 	if (unlikely(ptr))
 		goto out_hooks;
 
-	cache_alloc_debugcheck_before(cachep, flags);
 	local_irq_save(save_flags);
 
 	if (nodeid == NUMA_NO_NODE)
···
 	if (unlikely(objp))
 		goto out;
 
-	cache_alloc_debugcheck_before(cachep, flags);
 	local_irq_save(save_flags);
 	objp = __do_cache_alloc(cachep, flags);
 	local_irq_restore(save_flags);
···
 	s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
 	if (!s)
 		return 0;
-
-	cache_alloc_debugcheck_before(s, flags);
 
 	local_irq_disable();
 	for (i = 0; i < size; i++) {