mm: add more BUILD_BUG_ONs to gfp_migratetype()

gfp_migratetype() also expects GFP_RECLAIMABLE and
GFP_MOVABLE|GFP_RECLAIMABLE to be shiftable into MIGRATE_* enum values, so
add some more BUILD_BUG_ONs to reflect this assumption.

Link: https://linux-review.googlesource.com/id/Iae64e2182f75c3aca776a486b71a72571d66d83e
Link: https://lkml.kernel.org/r/20220726230241.3770532-1-pcc@google.com
Signed-off-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index f314be5..ea6cb93 100644 (file)
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -18,6 +18,9 @@ static inline int gfp_migratetype(const gfp_t gfp_flags)
        VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
        BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
        BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
+       BUILD_BUG_ON((___GFP_RECLAIMABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_RECLAIMABLE);
+       BUILD_BUG_ON(((___GFP_MOVABLE | ___GFP_RECLAIMABLE) >>
+                     GFP_MOVABLE_SHIFT) != MIGRATE_HIGHATOMIC);
 
        if (unlikely(page_group_by_mobility_disabled))
                return MIGRATE_UNMOVABLE;