sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h>

We are going to split <linux/sched/mm.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/mm.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

The APIs that are going to be moved first are:

   mm_alloc()
   __mmdrop()
   mmdrop()
   mmdrop_async_fn()
   mmdrop_async()
   mmget_not_zero()
   mmput()
   mmput_async()
   get_task_mm()
   mm_access()
   mm_release()

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 34bce5c..212a2af 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2,6 +2,7 @@
 
 #include <linux/mm.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/mmu_notifier.h>
 #include <linux/rmap.h>
 #include <linux/swap.h>
diff --git a/mm/ksm.c b/mm/ksm.c
index 520e4c3..5632c9d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -19,6 +19,7 @@
 #include <linux/fs.h>
 #include <linux/mman.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/rwsem.h>
 #include <linux/pagemap.h>
 #include <linux/rmap.h>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 45867e4..c52ec89 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -35,6 +35,7 @@
 #include <linux/memcontrol.h>
 #include <linux/cgroup.h>
 #include <linux/mm.h>
+#include <linux/sched/mm.h>
 #include <linux/shmem_fs.h>
 #include <linux/hugetlb.h>
 #include <linux/pagemap.h>
diff --git a/mm/memory.c b/mm/memory.c
index 14fc0b4..b0495ec 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -40,6 +40,7 @@
 
 #include <linux/kernel_stat.h>
 #include <linux/mm.h>
+#include <linux/sched/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/mman.h>
 #include <linux/swap.h>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1e7873e..9089241 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -73,6 +73,7 @@
 #include <linux/hugetlb.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/nodemask.h>
 #include <linux/cpuset.h>
 #include <linux/slab.h>
diff --git a/mm/migrate.c b/mm/migrate.c
index 2c63ac0..9a0897a 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -40,6 +40,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/page_idle.h>
 #include <linux/page_owner.h>
+#include <linux/sched/mm.h>
 
 #include <asm/tlbflush.h>
 
diff --git a/mm/mmu_context.c b/mm/mmu_context.c
index daf67bb..8888b12 100644
--- a/mm/mmu_context.c
+++ b/mm/mmu_context.c
@@ -5,6 +5,7 @@
 
 #include <linux/mm.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/mmu_context.h>
 #include <linux/export.h>
 
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 32bc9f2..a7652ac 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -17,6 +17,7 @@
 #include <linux/srcu.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/slab.h>
 
 /* global SRCU for all MMs */
diff --git a/mm/nommu.c b/mm/nommu.c
index aae06e8..79abed5 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -17,6 +17,7 @@
 
 #include <linux/export.h>
 #include <linux/mm.h>
+#include <linux/sched/mm.h>
 #include <linux/vmacache.h>
 #include <linux/mman.h>
 #include <linux/swap.h>
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 51c0918..d289366 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -22,6 +22,7 @@
 #include <linux/err.h>
 #include <linux/gfp.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/swap.h>
 #include <linux/timex.h>
 #include <linux/jiffies.h>
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 84d0c7e..8973cd2 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -12,6 +12,7 @@
 #include <linux/mm.h>
 #include <linux/uio.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/highmem.h>
 #include <linux/ptrace.h>
 #include <linux/slab.h>
diff --git a/mm/rmap.c b/mm/rmap.c
index 8774791..0367a05 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -46,6 +46,7 @@
  */
 
 #include <linux/mm.h>
+#include <linux/sched/mm.h>
 #include <linux/pagemap.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index fadc6a1..ff2bf3f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/mm.h>
+#include <linux/sched/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/mman.h>
 #include <linux/slab.h>
diff --git a/mm/util.c b/mm/util.c
index b8f5388..14f4e13 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -5,6 +5,7 @@
 #include <linux/export.h>
 #include <linux/err.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/security.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>