mm: fix CONFIG_MEMCG build for AS_KERNEL_FILE

this needs to be folded into

mm/filemap: add AS_KERNEL_FILE

for it to build with CONFIG_MEMCG unset. Apologies for the churn.

Link: https://lkml.kernel.org/r/6de59ddeec81b5c294d337c001ba0061631d4ec6.1755816635.git.boris@bur.io
Signed-off-by: Boris Burkov <boris@bur.io>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qu Wenruo <wqu@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 9fa3afc90dd520d3b2c8b1f4e5cbf83627e1ab9a..e693978b2022903d7789408a9eb15735dc033433 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1059,6 +1059,8 @@ extern int mem_cgroup_init(void);
 
 #define MEM_CGROUP_ID_SHIFT    0
 
+#define root_mem_cgroup                (NULL)
+
 static inline struct mem_cgroup *folio_memcg(struct folio *folio)
 {
        return NULL;