sparse: use identifiers to define address spaces

Currently, address spaces in warnings are displayed as '<asn:X>' with
'X' being the address space's arbitrary number.

But since sparse v0.6.0-rc1 (late December 2018), sparse allows you to
define the address spaces using an identifier instead of a number.  This
identifier is then directly used in the warnings.

So, use the identifiers '__user', '__iomem', '__percpu' & '__rcu' for
the corresponding address spaces.  The default address space, __kernel,
being not displayed in warnings, stays defined as '0'.

With this change, warnings that used to be displayed as:

	cast removes address space '<asn:1>' of expression
	... void [noderef] <asn:2> *

will now be displayed as:

	cast removes address space '__user' of expression
	... void [noderef] __iomem *

This also moves the __kernel annotation to be the first one, since it is
quite different from the others because it's the default one, and so:

 - it's never displayed

 - it's normally not needed, nor in type annotations, nor in cast
   between address spaces. The only time it's needed is when it's
   combined with a typeof to express "the same type as this one but
   without the address space"

 - it can't be defined with a name, '0' must be used.

So, it seemed strange to me to have it in the middle of the other
ones.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/compiler_types.h

@@ -5,20 +5,20 @@
 #ifndef __ASSEMBLY__
 
 #ifdef __CHECKER__
-# define __user		__attribute__((noderef, address_space(1)))
 # define __kernel	__attribute__((address_space(0)))
+# define __user		__attribute__((noderef, address_space(__user)))
 # define __safe		__attribute__((safe))
 # define __force	__attribute__((force))
 # define __nocast	__attribute__((nocast))
-# define __iomem	__attribute__((noderef, address_space(2)))
+# define __iomem	__attribute__((noderef, address_space(__iomem)))
 # define __must_hold(x)	__attribute__((context(x,1,1)))
 # define __acquires(x)	__attribute__((context(x,0,1)))
 # define __releases(x)	__attribute__((context(x,1,0)))
 # define __acquire(x)	__context__(x,1)
 # define __release(x)	__context__(x,-1)
 # define __cond_lock(x,c)	((c) ? ({ __acquire(x); 1; }) : 0)
-# define __percpu	__attribute__((noderef, address_space(3)))
-# define __rcu		__attribute__((noderef, address_space(4)))
+# define __percpu	__attribute__((noderef, address_space(__percpu)))
+# define __rcu		__attribute__((noderef, address_space(__rcu)))
 # define __private	__attribute__((noderef))
 extern void __chk_user_ptr(const volatile void __user *);
 extern void __chk_io_ptr(const volatile void __iomem *);