[RFC PATCH 2/8] thread_info: allow custom in-task thread_info

[Andy Lutomirski]

On Thu, Sep 15, 2016 at 6:49 AM, Mark Rutland <mark.rutland at arm.com> wrote:
> Currently, task_struct is defined in <linux/sched.h>, which (indirectly)
> pulls in a number of low-level arch headers such as <asm/preempt.h>
> through a number of other headers. Thus, code and structures in these
> headers can't rely on the definition of task_struct. Some of these
> headers are necessary for the definition of task_struct, so moving
> task_struct into its own header is insufficient tio avoid circular
> includes.

The flippant answer is to fix the headers, but I tried that myself and
gave up :(

But how about this slightly less duplicative alternative:

struct thread_info {
#ifdef arch_thread_info
  struct arch_thread_info arch_ti;
#endif
};