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

We are going to split <linux/sched/task_stack.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/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

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

Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
index 698d51a..c8240a1 100644
--- a/include/linux/elfcore.h
+++ b/include/linux/elfcore.h
@@ -3,6 +3,8 @@
 
 #include <linux/user.h>
 #include <linux/bug.h>
+#include <linux/sched/task_stack.h>
+
 #include <asm/elf.h>
 #include <uapi/linux/elfcore.h>
 
diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
index a5f98d5..9b7dd59 100644
--- a/include/linux/perf_regs.h
+++ b/include/linux/perf_regs.h
@@ -1,6 +1,8 @@
 #ifndef _LINUX_PERF_REGS_H
 #define _LINUX_PERF_REGS_H
 
+#include <linux/sched/task_stack.h>
+
 struct perf_regs {
 	__u64		abi;
 	struct pt_regs	*regs;
diff --git a/include/linux/sched/task_stack.h b/include/linux/sched/task_stack.h
new file mode 100644
index 0000000..933cd49
--- /dev/null
+++ b/include/linux/sched/task_stack.h
@@ -0,0 +1,6 @@
+#ifndef _LINUX_SCHED_TASK_STACK_H
+#define _LINUX_SCHED_TASK_STACK_H
+
+#include <linux/sched.h>
+
+#endif /* _LINUX_SCHED_TASK_STACK_H */