[RFC][PATCH -mm 2/3] freezer: Introduce freezer_flags

["Rafael J. Wysocki" <rjw@sisk.pl>]

From: Rafael J. Wysocki <rjw@sisk.pl>

Move all of the freezer-related flags to a separate field in task_struct and
introduce functions to operate them using set_bit() etc.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 Documentation/power/kernel_threads.txt |    2 -
 Documentation/power/swsusp.txt         |    6 +--
 arch/i386/kernel/apm.c                 |    2 -
 drivers/block/loop.c                   |    2 -
 drivers/char/apm-emulation.c           |    6 +--
 drivers/ieee1394/ieee1394_core.c       |    2 -
 drivers/md/md.c                        |    2 -
 drivers/mmc/card/queue.c               |    3 +
 drivers/mtd/mtd_blkdevs.c              |    3 +
 drivers/scsi/libsas/sas_scsi_host.c    |    2 -
 drivers/scsi/scsi_error.c              |    2 -
 drivers/usb/storage/usb.c              |    2 -
 include/asm-arm/thread_info.h          |    2 -
 include/asm-blackfin/thread_info.h     |    2 -
 include/asm-frv/thread_info.h          |    2 -
 include/asm-i386/thread_info.h         |    2 -
 include/asm-ia64/thread_info.h         |    2 -
 include/asm-mips/thread_info.h         |    2 -
 include/asm-powerpc/thread_info.h      |    2 -
 include/asm-sh/thread_info.h           |    2 -
 include/asm-x86_64/thread_info.h       |    2 -
 include/linux/freezer.h                |   65 ++++++++++++++++++++++++++-------
 include/linux/sched.h                  |    8 ++--
 kernel/fork.c                          |    2 -
 kernel/freezer.c                       |    2 -
 kernel/rcutorture.c                    |    4 +-
 kernel/sched.c                         |    2 -
 kernel/softirq.c                       |    2 -
 kernel/softlockup.c                    |    2 -
 kernel/workqueue.c                     |    2 -
 30 files changed, 83 insertions(+), 58 deletions(-)

Index: linux-2.6.21-rc6-mm1/include/linux/sched.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/linux/sched.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/linux/sched.h	2007-04-22 20:55:01.000000000 +0200
@@ -1002,7 +1002,10 @@ struct task_struct {
 	/* Deadlock detection and priority inheritance handling */
 	struct rt_mutex_waiter *pi_blocked_on;
 #endif
-
+#ifdef CONFIG_FREEZER
+	/* Used by the process freezer, defined in freezer.h */
+	unsigned int freezer_flags;
+#endif
 #ifdef CONFIG_DEBUG_MUTEXES
 	/* mutex deadlock detection */
 	struct mutex_waiter *blocked_on;
@@ -1187,8 +1190,6 @@ static inline void put_task_struct(struc
 #define PF_MEMALLOC	0x00000800	/* Allocating memory */
 #define PF_FLUSHER	0x00001000	/* responsible for disk writeback */
 #define PF_USED_MATH	0x00002000	/* if unset the fpu must be initialized before use */
-#define PF_NOFREEZE	0x00008000	/* this thread should not be frozen */
-#define PF_FROZEN	0x00010000	/* frozen for system suspend */
 #define PF_FSTRANS	0x00020000	/* inside a filesystem transaction */
 #define PF_KSWAPD	0x00040000	/* I am kswapd */
 #define PF_SWAPOFF	0x00080000	/* I am in swapoff */
@@ -1200,7 +1201,6 @@ static inline void put_task_struct(struc
 #define PF_SPREAD_SLAB	0x02000000	/* Spread some slab caches over cpuset */
 #define PF_MEMPOLICY	0x10000000	/* Non-default NUMA mempolicy */
 #define PF_MUTEX_TESTER	0x20000000	/* Thread belongs to the rt mutex tester */
-#define PF_FREEZER_SKIP	0x40000000	/* Freezer should not count it as freezeable */
 
 /*
  * Only the _current_ task can read/write to tsk->flags, but other
Index: linux-2.6.21-rc6-mm1/include/asm-arm/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-arm/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-arm/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -147,7 +147,6 @@ extern void iwmmxt_task_switch(struct th
 #define TIF_POLLING_NRFLAG	16
 #define TIF_USING_IWMMXT	17
 #define TIF_MEMDIE		18
-#define TIF_FREEZE		19
 
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
@@ -155,7 +154,6 @@ extern void iwmmxt_task_switch(struct th
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 #define _TIF_USING_IWMMXT	(1 << TIF_USING_IWMMXT)
-#define _TIF_FREEZE		(1 << TIF_FREEZE)
 
 /*
  * Change these and you break ASM code in entry-common.S
Index: linux-2.6.21-rc6-mm1/include/asm-blackfin/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-blackfin/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-blackfin/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -125,7 +125,6 @@ static inline struct thread_info *curren
 					   TIF_NEED_RESCHED */
 #define TIF_MEMDIE              5
 #define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
-#define TIF_FREEZE              7       /* is freezing for suspend */
 #define TIF_SINGLESTEP		8       /* restore singlestep on return to user mode */
 
 /* as above, but as bit values */
@@ -135,7 +134,6 @@ static inline struct thread_info *curren
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE             (1<<TIF_FREEZE)
 #define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)
 
 #define _TIF_WORK_MASK		0x0000FFFE	/* work to do on interrupt/exception return */
Index: linux-2.6.21-rc6-mm1/include/asm-frv/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-frv/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-frv/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -116,7 +116,6 @@ register struct thread_info *__current_t
 #define TIF_RESTORE_SIGMASK	6	/* restore signal mask in do_signal() */
 #define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_MEMDIE		17	/* OOM killer killed process */
-#define TIF_FREEZE		18	/* freezing for suspend */
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
@@ -126,7 +125,6 @@ register struct thread_info *__current_t
 #define _TIF_IRET		(1 << TIF_IRET)
 #define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE		(1 << TIF_FREEZE)
 
 #define _TIF_WORK_MASK		0x0000FFFE	/* work to do on interrupt/exception return */
 #define _TIF_ALLWORK_MASK	0x0000FFFF	/* work to do on any return to u-space */
Index: linux-2.6.21-rc6-mm1/include/asm-i386/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-i386/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-i386/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -135,7 +135,6 @@ static inline struct thread_info *curren
 #define TIF_MEMDIE		16
 #define TIF_DEBUG		17	/* uses debug registers */
 #define TIF_IO_BITMAP		18	/* uses I/O bitmap */
-#define TIF_FREEZE		19	/* is freezing for suspend */
 #define TIF_FORCED_TF		20	/* true if TF in eflags artificially */
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
@@ -149,7 +148,6 @@ static inline struct thread_info *curren
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
 #define _TIF_DEBUG		(1<<TIF_DEBUG)
 #define _TIF_IO_BITMAP		(1<<TIF_IO_BITMAP)
-#define _TIF_FREEZE		(1<<TIF_FREEZE)
 #define _TIF_FORCED_TF		(1<<TIF_FORCED_TF)
 
 /* work to do on interrupt/exception return */
Index: linux-2.6.21-rc6-mm1/include/asm-ia64/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-ia64/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-ia64/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -89,7 +89,6 @@ struct thread_info {
 #define TIF_MEMDIE		17
 #define TIF_MCA_INIT		18	/* this task is processing MCA or INIT */
 #define TIF_DB_DISABLED		19	/* debug trap disabled for fsyscall */
-#define TIF_FREEZE		20	/* is freezing for suspend */
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
@@ -101,7 +100,6 @@ struct thread_info {
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 #define _TIF_MCA_INIT		(1 << TIF_MCA_INIT)
 #define _TIF_DB_DISABLED	(1 << TIF_DB_DISABLED)
-#define _TIF_FREEZE		(1 << TIF_FREEZE)
 
 /* "work to do on user-return" bits */
 #define TIF_ALLWORK_MASK	(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
Index: linux-2.6.21-rc6-mm1/include/asm-mips/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-mips/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-mips/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -118,7 +118,6 @@ register struct thread_info *__current_t
 #define TIF_USEDFPU		16	/* FPU was used by this task this quantum (SMP) */
 #define TIF_POLLING_NRFLAG	17	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_MEMDIE		18
-#define TIF_FREEZE		19
 #define TIF_ALLOW_FP_IN_KERNEL	20
 #define TIF_SYSCALL_TRACE	31	/* syscall trace active */
 
@@ -131,7 +130,6 @@ register struct thread_info *__current_t
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
 #define _TIF_USEDFPU		(1<<TIF_USEDFPU)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE		(1<<TIF_FREEZE)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK		(0x0000ffef & ~_TIF_SECCOMP)
Index: linux-2.6.21-rc6-mm1/include/asm-powerpc/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-powerpc/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-powerpc/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -122,7 +122,6 @@ static inline struct thread_info *curren
 #define TIF_RESTOREALL		12	/* Restore all regs (implies NOERROR) */
 #define TIF_NOERROR		14	/* Force successful syscall return */
 #define TIF_RESTORE_SIGMASK	15	/* Restore signal mask in do_signal */
-#define TIF_FREEZE		16	/* Freezing for suspend */
 
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
@@ -139,7 +138,6 @@ static inline struct thread_info *curren
 #define _TIF_RESTOREALL		(1<<TIF_RESTOREALL)
 #define _TIF_NOERROR		(1<<TIF_NOERROR)
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE		(1<<TIF_FREEZE)
 #define _TIF_SYSCALL_T_OR_A	(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
 
 #define _TIF_USER_WORK_MASK	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
Index: linux-2.6.21-rc6-mm1/include/asm-sh/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-sh/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-sh/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -115,7 +115,6 @@ static inline struct thread_info *curren
 #define TIF_USEDFPU		16	/* FPU was used by this task this quantum (SMP) */
 #define TIF_POLLING_NRFLAG	17	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_MEMDIE		18
-#define TIF_FREEZE		19
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
@@ -125,7 +124,6 @@ static inline struct thread_info *curren
 #define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)
 #define _TIF_USEDFPU		(1<<TIF_USEDFPU)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE		(1<<TIF_FREEZE)
 
 #define _TIF_WORK_MASK		0x000000FE	/* work to do on interrupt/exception return */
 #define _TIF_ALLWORK_MASK	0x000000FF	/* work to do on any return to u-space */
Index: linux-2.6.21-rc6-mm1/include/asm-x86_64/thread_info.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/asm-x86_64/thread_info.h	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/asm-x86_64/thread_info.h	2007-04-22 20:55:01.000000000 +0200
@@ -122,7 +122,6 @@ static inline struct thread_info *stack_
 #define TIF_MEMDIE		20
 #define TIF_DEBUG		21	/* uses debug registers */
 #define TIF_IO_BITMAP		22	/* uses I/O bitmap */
-#define TIF_FREEZE		23	/* is freezing for suspend */
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
@@ -139,7 +138,6 @@ static inline struct thread_info *stack_
 #define _TIF_ABI_PENDING	(1<<TIF_ABI_PENDING)
 #define _TIF_DEBUG		(1<<TIF_DEBUG)
 #define _TIF_IO_BITMAP		(1<<TIF_IO_BITMAP)
-#define _TIF_FREEZE		(1<<TIF_FREEZE)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
Index: linux-2.6.21-rc6-mm1/include/linux/freezer.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/linux/freezer.h	2007-04-22 20:54:59.000000000 +0200
+++ linux-2.6.21-rc6-mm1/include/linux/freezer.h	2007-04-22 20:55:01.000000000 +0200
@@ -3,12 +3,33 @@
 #include <linux/sched.h>
 
 #ifdef CONFIG_FREEZER
+
+/*
+ *	Per task flags used by the freezer
+ *
+ *	They should not be referred to directly outside of this file.
+ */
+#define TFF_NOFREEZE	0	/* task should not be frozen */
+#define TFF_FREEZE	8	/* task should go to the refrigerator ASAP */
+#define TFF_SKIP	9	/* do not count this task as freezable */
+#define TFF_FROZEN	10	/* task is frozen */
+
 /*
  * Check if a process has been frozen
  */
 static inline int frozen(struct task_struct *p)
 {
-	return p->flags & PF_FROZEN;
+	return test_bit(TFF_FROZEN, &p->freezer_flags);
+}
+
+static inline void set_frozen_flag(struct task_struct *p)
+{
+	set_bit(TFF_FROZEN, &p->freezer_flags);
+}
+
+static inline void clear_frozen_flag(struct task_struct *p)
+{
+	clear_bit(TFF_FROZEN, &p->freezer_flags);
 }
 
 /*
@@ -16,7 +37,7 @@ static inline int frozen(struct task_str
  */
 static inline int freezing(struct task_struct *p)
 {
-	return test_tsk_thread_flag(p, TIF_FREEZE);
+	return test_bit(TFF_FREEZE, &p->freezer_flags);
 }
 
 /*
@@ -24,15 +45,31 @@ static inline int freezing(struct task_s
  */
 static inline void freeze(struct task_struct *p)
 {
-	set_tsk_thread_flag(p, TIF_FREEZE);
+	set_bit(TFF_FREEZE, &p->freezer_flags);
 }
 
 /*
- * Sometimes we may need to cancel the previous 'freeze' request
+ * Cancel the previous 'freeze' request
  */
 static inline void do_not_freeze(struct task_struct *p)
 {
-	clear_tsk_thread_flag(p, TIF_FREEZE);
+	clear_bit(TFF_FREEZE, &p->freezer_flags);
+}
+
+/*
+ * Check if the task wants to be exempted from freezing
+ */
+static inline int freezer_should_exempt(struct task_struct *p)
+{
+	return test_bit(TFF_NOFREEZE, &p->freezer_flags);
+}
+
+/*
+ * Tell the freezer to exempt this task from freezing
+ */
+static inline void freezer_exempt(struct task_struct *p)
+{
+	set_bit(TFF_NOFREEZE, &p->freezer_flags);
 }
 
 /*
@@ -48,12 +85,12 @@ static inline int thaw_process(struct ta
 {
 	task_lock(p);
 	if (frozen(p)) {
-		p->flags &= ~PF_FROZEN;
+		clear_frozen_flag(p);
 		task_unlock(p);
 		wake_up_process(p);
 		return 1;
 	}
-	clear_tsk_thread_flag(p, TIF_FREEZE);
+	do_not_freeze(p);
 	task_unlock(p);
 	return 0;
 }
@@ -63,9 +100,9 @@ static inline int thaw_process(struct ta
  */
 static inline void frozen_process(struct task_struct *p)
 {
-	p->flags |= PF_FROZEN;
+	set_frozen_flag(p);
 	wmb();
-	clear_tsk_thread_flag(p, TIF_FREEZE);
+	do_not_freeze(p);
 }
 
 extern void refrigerator(void);
@@ -102,7 +139,7 @@ static inline int try_to_freeze(void)
 static inline void freezer_do_not_count(void)
 {
 	if (current->mm)
-		current->flags |= PF_FREEZER_SKIP;
+		set_bit(TFF_SKIP, &current->freezer_flags);
 }
 
 /*
@@ -112,7 +149,7 @@ static inline void freezer_do_not_count(
 static inline void freezer_count(void)
 {
 	if (current->mm) {
-		current->flags &= ~PF_FREEZER_SKIP;
+		clear_bit(TFF_SKIP, &current->freezer_flags);
 		try_to_freeze();
 	}
 }
@@ -122,13 +159,17 @@ static inline void freezer_count(void)
  */
 static inline int freezer_should_skip(struct task_struct *p)
 {
-	return !!(p->flags & PF_FREEZER_SKIP);
+	return test_bit(TFF_SKIP, &current->freezer_flags);
 }
 
 #else
 static inline int frozen(struct task_struct *p) { return 0; }
+static inline void set_frozen_flag(struct task_struct *p) {}
+static inline void clear_frozen_flag(struct task_struct *p) {}
 static inline int freezing(struct task_struct *p) { return 0; }
 static inline void freeze(struct task_struct *p) { BUG(); }
+static inline int freezer_should_exempt(struct task_struct *p) { return 0; }
+static inline void freezer_exempt(struct task_struct *p) {}
 static inline int thaw_process(struct task_struct *p) { return 1; }
 static inline void frozen_process(struct task_struct *p) { BUG(); }
 
Index: linux-2.6.21-rc6-mm1/kernel/sched.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/sched.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/sched.c	2007-04-22 20:55:01.000000000 +0200
@@ -5431,7 +5431,7 @@ migration_call(struct notifier_block *nf
 		p = kthread_create(migration_thread, hcpu, "migration/%d",cpu);
 		if (IS_ERR(p))
 			return NOTIFY_BAD;
-		p->flags |= PF_NOFREEZE;
+		freezer_exempt(p);
 		kthread_bind(p, cpu);
 		/* Must be high prio: stop_machine expects to yield to it. */
 		rq = task_rq_lock(p, &flags);
Index: linux-2.6.21-rc6-mm1/arch/i386/kernel/apm.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/arch/i386/kernel/apm.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/arch/i386/kernel/apm.c	2007-04-22 20:55:01.000000000 +0200
@@ -2313,7 +2313,7 @@ static int __init apm_init(void)
 		remove_proc_entry("apm", NULL);
 		return err;
 	}
-	kapmd_task->flags |= PF_NOFREEZE;
+	freezer_exempt(kapmd_task);
 	wake_up_process(kapmd_task);
 
 	if (num_online_cpus() > 1 && !smp ) {
Index: linux-2.6.21-rc6-mm1/drivers/block/loop.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/block/loop.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/block/loop.c	2007-04-22 20:55:01.000000000 +0200
@@ -586,7 +586,7 @@ static int loop_thread(void *data)
 	 * hence, it mustn't be stopped at all
 	 * because it could be indirectly used during suspension
 	 */
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	set_user_nice(current, -20);
 
Index: linux-2.6.21-rc6-mm1/drivers/char/apm-emulation.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/char/apm-emulation.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/char/apm-emulation.c	2007-04-22 20:55:01.000000000 +0200
@@ -336,7 +336,7 @@ apm_ioctl(struct inode * inode, struct f
 			 * threads.
 			 */
 			flags = current->flags;
-			current->flags |= PF_NOFREEZE;
+			freezer_exempt(current);
 
 			wait_event(apm_suspend_waitqueue,
 				   as->suspend_state == SUSPEND_DONE);
@@ -372,7 +372,7 @@ apm_ioctl(struct inode * inode, struct f
 			 * threads.
 			 */
 			flags = current->flags;
-			current->flags |= PF_NOFREEZE;
+			freezer_exempt(current);
 
 			wait_event_interruptible(apm_suspend_waitqueue,
 					 as->suspend_state == SUSPEND_DONE);
@@ -601,7 +601,7 @@ static int __init apm_init(void)
 		kapmd_tsk = NULL;
 		return ret;
 	}
-	kapmd_tsk->flags |= PF_NOFREEZE;
+	freezer_exempt(kapmd_tsk);
 	wake_up_process(kapmd_tsk);
 
 #ifdef CONFIG_PROC_FS
Index: linux-2.6.21-rc6-mm1/drivers/ieee1394/ieee1394_core.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/ieee1394/ieee1394_core.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/ieee1394/ieee1394_core.c	2007-04-22 20:55:01.000000000 +0200
@@ -1134,7 +1134,7 @@ static int hpsbpkt_thread(void *__hi)
 	struct list_head tmp;
 	int may_schedule;
 
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	while (!kthread_should_stop()) {
 
Index: linux-2.6.21-rc6-mm1/drivers/md/md.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/md/md.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/md/md.c	2007-04-22 20:55:01.000000000 +0200
@@ -4541,7 +4541,7 @@ static int md_thread(void * arg)
 	 * many dirty RAID5 blocks.
 	 */
 
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 	allow_signal(SIGKILL);
 	while (!kthread_should_stop()) {
 
Index: linux-2.6.21-rc6-mm1/drivers/mmc/card/queue.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/mmc/card/queue.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/mmc/card/queue.c	2007-04-22 20:55:01.000000000 +0200
@@ -66,7 +66,8 @@ static int mmc_queue_thread(void *d)
 	 * Set iothread to ensure that we aren't put to sleep by
 	 * the process freezing.  We handle suspension ourselves.
 	 */
-	current->flags |= PF_MEMALLOC|PF_NOFREEZE;
+	current->flags |= PF_MEMALLOC;
+	freezer_exempt(current);
 
 	down(&mq->thread_sem);
 	do {
Index: linux-2.6.21-rc6-mm1/drivers/mtd/mtd_blkdevs.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/mtd/mtd_blkdevs.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/mtd/mtd_blkdevs.c	2007-04-22 20:55:01.000000000 +0200
@@ -82,7 +82,8 @@ static int mtd_blktrans_thread(void *arg
 	struct request_queue *rq = tr->blkcore_priv->rq;
 
 	/* we might get involved when memory gets low, so use PF_MEMALLOC */
-	current->flags |= PF_MEMALLOC | PF_NOFREEZE;
+	current->flags |= PF_MEMALLOC;
+	freezer_exempt(current);
 
 	daemonize("%sd", tr->name);
 
Index: linux-2.6.21-rc6-mm1/drivers/scsi/libsas/sas_scsi_host.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/scsi/libsas/sas_scsi_host.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/scsi/libsas/sas_scsi_host.c	2007-04-22 20:55:01.000000000 +0200
@@ -871,7 +871,7 @@ static int sas_queue_thread(void *_sas_h
 	struct scsi_core *core = &sas_ha->core;
 
 	daemonize("sas_queue_%d", core->shost->host_no);
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	complete(&queue_th_comp);
 
Index: linux-2.6.21-rc6-mm1/drivers/scsi/scsi_error.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/scsi/scsi_error.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/scsi/scsi_error.c	2007-04-22 20:55:01.000000000 +0200
@@ -1536,7 +1536,7 @@ int scsi_error_handler(void *data)
 {
 	struct Scsi_Host *shost = data;
 
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	/*
 	 * We use TASK_INTERRUPTIBLE so that the thread is not
Index: linux-2.6.21-rc6-mm1/drivers/usb/storage/usb.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/drivers/usb/storage/usb.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/drivers/usb/storage/usb.c	2007-04-22 20:55:01.000000000 +0200
@@ -301,7 +301,7 @@ static int usb_stor_control_thread(void 
 	struct us_data *us = (struct us_data *)__us;
 	struct Scsi_Host *host = us_to_host(us);
 
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	for(;;) {
 		try_to_freeze();
Index: linux-2.6.21-rc6-mm1/kernel/fork.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/fork.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/fork.c	2007-04-22 20:55:01.000000000 +0200
@@ -922,7 +922,7 @@ static inline void copy_flags(unsigned l
 {
 	unsigned long new_flags = p->flags;
 
-	new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE);
+	new_flags &= ~PF_SUPERPRIV;
 	new_flags |= PF_FORKNOEXEC;
 	new_flags |= PF_STARTING;
 	p->flags = new_flags;
Index: linux-2.6.21-rc6-mm1/kernel/rcutorture.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/rcutorture.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/rcutorture.c	2007-04-22 20:55:01.000000000 +0200
@@ -559,7 +559,7 @@ rcu_torture_fakewriter(void *arg)
 
 	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
 	set_user_nice(current, 19);
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	do {
 		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
@@ -590,7 +590,7 @@ rcu_torture_reader(void *arg)
 
 	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
 	set_user_nice(current, 19);
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	do {
 		idx = cur_ops->readlock();
Index: linux-2.6.21-rc6-mm1/kernel/softirq.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/softirq.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/softirq.c	2007-04-22 20:55:01.000000000 +0200
@@ -490,7 +490,7 @@ void __init softirq_init(void)
 static int ksoftirqd(void * __bind_cpu)
 {
 	set_user_nice(current, 19);
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	set_current_state(TASK_INTERRUPTIBLE);
 
Index: linux-2.6.21-rc6-mm1/kernel/softlockup.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/softlockup.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/softlockup.c	2007-04-22 20:55:01.000000000 +0200
@@ -117,7 +117,7 @@ static int watchdog(void * __bind_cpu)
 	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 
 	sched_setscheduler(current, SCHED_FIFO, &param);
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 	/* initialize timestamp */
 	touch_softlockup_watchdog();
Index: linux-2.6.21-rc6-mm1/kernel/workqueue.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/workqueue.c	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/workqueue.c	2007-04-22 20:55:01.000000000 +0200
@@ -292,7 +292,7 @@ static int worker_thread(void *__cwq)
 	struct k_sigaction sa;
 
 	if (!cwq->wq->freezeable)
-		current->flags |= PF_NOFREEZE;
+		freezer_exempt(current);
 
 	/*
 	 * We inherited MPOL_INTERLEAVE from the booting kernel.
Index: linux-2.6.21-rc6-mm1/kernel/freezer.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/freezer.c	2007-04-22 20:54:59.000000000 +0200
+++ linux-2.6.21-rc6-mm1/kernel/freezer.c	2007-04-22 20:55:01.000000000 +0200
@@ -26,7 +26,7 @@
 static inline int freezeable(struct task_struct * p)
 {
 	if ((p == current) ||
-	    (p->flags & PF_NOFREEZE) ||
+	    freezer_should_exempt(p) ||
 	    (p->exit_state != 0))
 		return 0;
 	return 1;
Index: linux-2.6.21-rc6-mm1/Documentation/power/kernel_threads.txt
===================================================================
--- linux-2.6.21-rc6-mm1.orig/Documentation/power/kernel_threads.txt	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/Documentation/power/kernel_threads.txt	2007-04-22 20:55:01.000000000 +0200
@@ -32,7 +32,7 @@ like this:
 	 */
 	daemonize("usb-storage");
 
-	current->flags |= PF_NOFREEZE;
+	freezer_exempt(current);
 
 from drivers/usb/storage/usb.c::usb_stor_control_thread()
 
Index: linux-2.6.21-rc6-mm1/Documentation/power/swsusp.txt
===================================================================
--- linux-2.6.21-rc6-mm1.orig/Documentation/power/swsusp.txt	2007-04-22 19:37:42.000000000 +0200
+++ linux-2.6.21-rc6-mm1/Documentation/power/swsusp.txt	2007-04-22 20:55:01.000000000 +0200
@@ -152,8 +152,8 @@ add:
        try_to_freeze();
 
 If the thread is needed for writing the image to storage, you should
-instead set the PF_NOFREEZE process flag when creating the thread (and
-be very careful).
+instead use freezer_exempt() to mark the thread as nonfreezable when creating
+it (and be very careful).
 
 
 Q: What is the difference between "platform" and "shutdown"?