sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API dependency

Instead of including the full <linux/signal.h>, we are going to include the
types-only <linux/signal_types.h> header in <linux/sched.h>, to further
decouple the scheduler header from the signal headers.

This means that various files which relied on the full <linux/signal.h> need
to be updated to gain an explicit dependency on it.

Update the code that relies on sched.h's inclusion of the <linux/signal.h> header.

Acked-by: Linus Torvalds <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/arm64/kernel/sys_compat.c

···
 #include <linux/compat.h>
 #include <linux/personality.h>
 #include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>

drivers/gpu/drm/i915/i915_gem_request.c

···
 #include <linux/dma-fence-array.h>
 #include <linux/sched.h>
 #include <linux/sched/clock.h>
+#include <linux/sched/signal.h>
 
 #include "i915_drv.h"
 

drivers/isdn/mISDN/stack.c

···
 #include <linux/mISDNif.h>
 #include <linux/kthread.h>
 #include <linux/sched.h>
+#include <linux/signal.h>
+
 #include "core.h"
 
 static u_int	*debug;

fs/btrfs/extent-tree.c

···
  * Boston, MA 021110-1307, USA.
  */
 #include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/pagemap.h>
 #include <linux/writeback.h>
 #include <linux/blkdev.h>

fs/btrfs/free-space-cache.c

···
 
 #include <linux/pagemap.h>
 #include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <linux/math64.h>
 #include <linux/ratelimit.h>

fs/buffer.c

···
  */
 
 #include <linux/kernel.h>
+#include <linux/sched/signal.h>
 #include <linux/syscalls.h>
 #include <linux/fs.h>
 #include <linux/iomap.h>

fs/ceph/addr.c

···
 #include <linux/slab.h>
 #include <linux/pagevec.h>
 #include <linux/task_io_accounting_ops.h>
+#include <linux/signal.h>
 
 #include "super.h"
 #include "mds_client.h"

fs/dax.c

···
 #include <linux/pagevec.h>
 #include <linux/pmem.h>
 #include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/uio.h>
 #include <linux/vmstat.h>
 #include <linux/pfn_t.h>

fs/ioctl.c

···
 #include <linux/writeback.h>
 #include <linux/buffer_head.h>
 #include <linux/falloc.h>
+#include <linux/sched/signal.h>
+
 #include "internal.h"
 
 #include <asm/ioctls.h>

fs/iomap.c

···
 #include <linux/buffer_head.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/dax.h>
+#include <linux/sched/signal.h>
+
 #include "internal.h"
 
 /*

fs/ocfs2/super.c

···
 #include <linux/seq_file.h>
 #include <linux/quotaops.h>
 #include <linux/cleancache.h>
+#include <linux/signal.h>
 
 #define CREATE_TRACE_POINTS
 #include "ocfs2_trace.h"

include/linux/sched.h

···
 #include <linux/signal.h>
 #include <linux/compiler.h>
 #include <linux/completion.h>
+#include <linux/signal_types.h>
 #include <linux/pid.h>
 #include <linux/percpu.h>
 #include <linux/topology.h>

include/linux/sched/signal.h

···
 #ifndef _LINUX_SCHED_SIGNAL_H
 #define _LINUX_SCHED_SIGNAL_H
 
+#include <linux/signal.h>
 #include <linux/cred.h>
 #include <linux/sched.h>
 #include <linux/sched/jobctl.h>

kernel/pid_namespace.c

···
 #include <linux/reboot.h>
 #include <linux/export.h>
 #include <linux/sched/task.h>
+#include <linux/sched/signal.h>
 
 struct pid_cache {
 	int nr_ids;

mm/page-writeback.c

···
 #include <linux/pagevec.h>
 #include <linux/timer.h>
 #include <linux/sched/rt.h>
+#include <linux/sched/signal.h>
 #include <linux/mm_inline.h>
 #include <trace/events/writeback.h>