[PATCH 32/35] cpumask: cpu_all_mask and cpu_none_mask.

[Mike Travis <travis@sgi.com>]

Instead of CPU_MASK_ALL_PTR and the SMP-only cpu_mask_all, this makes
cpu_all_mask and cpu_none_mask which are const cpumask pointers which
always exist.

From: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
---
 include/linux/cpumask.h |   16 ++++++++++------
 init/main.c             |    7 +------
 kernel/cpu.c            |    2 ++
 kernel/kmod.c           |    2 +-
 kernel/kthread.c        |    4 ++--
 kernel/sched.c          |    2 +-
 6 files changed, 17 insertions(+), 16 deletions(-)

--- linux-2.6.28.orig/include/linux/cpumask.h
+++ linux-2.6.28/include/linux/cpumask.h
@@ -117,6 +117,7 @@ struct cpumask
 typedef struct cpumask cpumask_t;
 extern cpumask_t _unused_cpumask_arg_;
 
+#define CPU_MASK_ALL_PTR	(cpu_all_mask)
 #define CPU_MASK_ALL		((cpumask_t){ CPU_BITS_ALL })
 #define CPU_MASK_NONE		((cpumask_t){ CPU_BITS_NONE })
 #define CPU_MASK_CPU0		((cpumask_t){ CPU_BITS_CPU0 })
@@ -175,6 +176,7 @@ extern cpumask_t _unused_cpumask_arg_;
 #define cpu_online_map		(*(cpumask_t *)cpu_online_mask)
 #define cpu_present_map		(*(cpumask_t *)cpu_present_mask)
 #define cpu_active_map		(*(cpumask_t *)cpu_active_mask)
+#define cpu_mask_all		(*(cpumask_t *)cpu_all_mask)
 /* End deprecated region. */
 
 #if NR_CPUS <= BITS_PER_LONG
@@ -411,8 +413,6 @@ static inline const struct cpumask *cpum
 	[BITS_TO_LONGS(CONFIG_NR_CPUS)-1] = CPU_MASK_LAST_WORD	\
 }
 
-#define CPU_MASK_ALL_PTR	(&CPU_MASK_ALL)
-
 #else
 
 #define CPU_BITS_ALL						\
@@ -421,10 +421,6 @@ static inline const struct cpumask *cpum
 	[BITS_TO_LONGS(CONFIG_NR_CPUS)-1] = CPU_MASK_LAST_WORD	\
 }
 
-/* cpu_mask_all is in init/main.c */
-extern cpumask_t cpu_mask_all;
-#define CPU_MASK_ALL_PTR	(&cpu_mask_all)
-
 #endif
 
 #define CPU_BITS_NONE						\
@@ -578,6 +574,14 @@ extern const struct cpumask *const cpu_o
 extern const struct cpumask *const cpu_present_mask;
 extern const struct cpumask *const cpu_active_mask;
 
+/* It's common to want to use cpu_all_mask in struct member initializers,
+ * so it has to refer to an address rather than a pointer. */
+extern const DECLARE_BITMAP(cpu_all_bits, CONFIG_NR_CPUS);
+#define cpu_all_mask to_cpumask(cpu_all_bits)
+
+/* First bits of cpu_bit_bitmap are in fact unset. */
+#define cpu_none_mask to_cpumask(cpu_bit_bitmap[0])
+
 #if NR_CPUS > 1
 #define num_online_cpus()	cpus_weight(cpu_online_map)
 #define num_possible_cpus()	cpus_weight(cpu_possible_map)
--- linux-2.6.28.orig/init/main.c
+++ linux-2.6.28/init/main.c
@@ -367,11 +367,6 @@ static inline void smp_prepare_cpus(unsi
 
 #else
 
-#if NR_CPUS > BITS_PER_LONG
-cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
-EXPORT_SYMBOL(cpu_mask_all);
-#endif
-
 /* Setup number of possible processor ids */
 /* nr_cpumask_bits is a real variable for large NR_CPUS. */
 #ifndef nr_cpumask_bits
@@ -869,7 +864,7 @@ static int __init kernel_init(void * unu
 	/*
 	 * init can run on any cpu.
 	 */
-	set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
+	set_cpus_allowed_ptr(current, cpu_all_mask);
 	/*
 	 * Tell the world that we're going to be the grim
 	 * reaper of innocent orphaned children.
--- linux-2.6.28.orig/kernel/cpu.c
+++ linux-2.6.28/kernel/cpu.c
@@ -489,6 +489,8 @@ EXPORT_SYMBOL(cpu_present_mask);
 static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly;
 const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits);
 EXPORT_SYMBOL(cpu_active_mask);
+const DECLARE_BITMAP(cpu_all_bits, CONFIG_NR_CPUS) = CPU_BITS_ALL;
+EXPORT_SYMBOL(cpu_all_bits);
 
 void set_cpu_possible(unsigned int cpu, bool possible)
 {
--- linux-2.6.28.orig/kernel/kmod.c
+++ linux-2.6.28/kernel/kmod.c
@@ -166,7 +166,7 @@ static int ____call_usermodehelper(void 
 	}
 
 	/* We can run anywhere, unlike our parent keventd(). */
-	set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
+	set_cpus_allowed_ptr(current, cpu_all_mask);
 
 	/*
 	 * Our parent is keventd, which runs with elevated scheduling priority.
--- linux-2.6.28.orig/kernel/kthread.c
+++ linux-2.6.28/kernel/kthread.c
@@ -107,7 +107,7 @@ static void create_kthread(struct kthrea
 		 */
 		sched_setscheduler(create->result, SCHED_NORMAL, &param);
 		set_user_nice(create->result, KTHREAD_NICE_LEVEL);
-		set_cpus_allowed_ptr(create->result, CPU_MASK_ALL_PTR);
+		set_cpus_allowed_ptr(create->result, cpu_all_mask);
 	}
 	complete(&create->done);
 }
@@ -238,7 +238,7 @@ int kthreadd(void *unused)
 	set_task_comm(tsk, "kthreadd");
 	ignore_signals(tsk);
 	set_user_nice(tsk, KTHREAD_NICE_LEVEL);
-	set_cpus_allowed_ptr(tsk, CPU_MASK_ALL_PTR);
+	set_cpus_allowed_ptr(tsk, cpu_all_mask);
 
 	current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;
 
--- linux-2.6.28.orig/kernel/sched.c
+++ linux-2.6.28/kernel/sched.c
@@ -6166,7 +6166,7 @@ static void move_task_off_dead_cpu(int d
  */
 static void migrate_nr_uninterruptible(struct rq *rq_src)
 {
-	struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR));
+	struct rq *rq_dest = cpu_rq(cpumask_any(cpu_online_mask));
 	unsigned long flags;
 
 	local_irq_save(flags);

--