[PATCH] Cleanup patch for process freezing

1. Establish a simple API for process freezing defined in linux/include/sched.h:

   frozen(process)		Check for frozen process
   freezing(process)		Check if a process is being frozen
   freeze(process)		Tell a process to freeze (go to refrigerator)
   thaw_process(process)	Restart process
   frozen_process(process)	Process is frozen now

2. Remove all references to PF_FREEZE and PF_FROZEN from all
   kernel sources except sched.h

3. Fix numerous locations where try_to_freeze is manually done by a driver

4. Remove the argument that is no longer necessary from two function calls.

5. Some whitespace cleanup

6. Clear potential race in refrigerator (provides an open window of PF_FREEZE
   cleared before setting PF_FROZEN, recalc_sigpending does not check
   PF_FROZEN).

This patch does not address the problem of freeze_processes() violating the rule
that a task may only modify its own flags by setting PF_FREEZE. This is not clean
in an SMP environment. freeze(process) is therefore not SMP safe!

Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

20 files changed, 22 insertions, 35 deletions

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 7f3d78de265c..7b838342f0a3 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1251,8 +1251,7 @@ static int kcdrwd(void *foobar)
                         VPRINTK("kcdrwd: wake up\n");
 
                         /* make swsusp happy with our thread */
-                        if (current->flags & PF_FREEZE)
-                                refrigerator(PF_FREEZE);
+                        try_to_freeze();
 
                         list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
                                 if (!pkt->sleep_time)
diff --git a/drivers/ieee1394/ieee1394_core.c b/drivers/ieee1394/ieee1394_core.c
index 2d9a9b74e687..629070b83a33 100644
--- a/drivers/ieee1394/ieee1394_core.c
+++ b/drivers/ieee1394/ieee1394_core.c
@@ -1041,10 +1041,8 @@ static int hpsbpkt_thread(void *__hi)
 
         while (1) {
                 if (down_interruptible(&khpsbpkt_sig)) {
-                        if (current->flags & PF_FREEZE) {
-                                refrigerator(0);
+                        if (try_to_freeze())
                                 continue;
-                        }
                         printk("khpsbpkt: received unexpected signal?!\n" );
                         break;
                 }
diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c
index 32abb6dda888..9a46c3b44bf8 100644
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -1510,7 +1510,7 @@ static int nodemgr_host_thread(void *__hi)
 
                 if (down_interruptible(&hi->reset_sem) ||
                     down_interruptible(&nodemgr_serialize)) {
-                        if (try_to_freeze(PF_FREEZE))
+                        if (try_to_freeze())
                                 continue;
                         printk("NodeMgr: received unexpected signal?!\n" );
                         break;
diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c
index e152d0fa0cdd..c77a82e46055 100644
--- a/drivers/input/gameport/gameport.c
+++ b/drivers/input/gameport/gameport.c
@@ -439,7 +439,7 @@ static int gameport_thread(void *nothing)
         do {
                 gameport_handle_events();
                 wait_event_interruptible(gameport_wait, !list_empty(&gameport_event_list));
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
         } while (!signal_pending(current));
 
         printk(KERN_DEBUG "gameport: kgameportd exiting\n");
diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index feab4970406e..341824c48529 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -344,7 +344,7 @@ static int serio_thread(void *nothing)
         do {
                 serio_handle_events();
                 wait_event_interruptible(serio_wait, !list_empty(&serio_event_list));
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
         } while (!signal_pending(current));
 
         printk(KERN_DEBUG "serio: kseriod exiting\n");
diff --git a/drivers/macintosh/therm_adt746x.c b/drivers/macintosh/therm_adt746x.c
index 5ba190ce14a0..c9ca1118e449 100644
--- a/drivers/macintosh/therm_adt746x.c
+++ b/drivers/macintosh/therm_adt746x.c
@@ -328,9 +328,7 @@ static int monitor_task(void *arg)
         struct thermostat* th = arg;
 
         while(!kthread_should_stop()) {
-                if (current->flags & PF_FREEZE)
-                        refrigerator(PF_FREEZE);
-
+                try_to_freeze();
                 msleep_interruptible(2000);
 
 #ifndef DEBUG
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0c6b5b6baff6..3802f7a17f16 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2976,8 +2976,7 @@ static int md_thread(void * arg)
                 wait_event_interruptible_timeout(thread->wqueue,
                                                  test_bit(THREAD_WAKEUP, &thread->flags),
                                                  thread->timeout);
-                if (current->flags & PF_FREEZE)
-                        refrigerator(PF_FREEZE);
+                try_to_freeze();
 
                 clear_bit(THREAD_WAKEUP, &thread->flags);
 
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index d6b7a9de471e..f11daae91cd4 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -391,8 +391,7 @@ static int dvb_frontend_thread(void *data)
                         break;
                 }
 
-                if (current->flags & PF_FREEZE)
-                        refrigerator(PF_FREEZE);
+                try_to_freeze();
 
                 if (down_interruptible(&fepriv->sem))
                         break;
diff --git a/drivers/media/video/msp3400.c b/drivers/media/video/msp3400.c
index 1b7d38e96f14..b4ee9dfe6d42 100644
--- a/drivers/media/video/msp3400.c
+++ b/drivers/media/video/msp3400.c
@@ -750,8 +750,7 @@ static int msp34xx_sleep(struct msp3400c *msp, int timeout)
 #endif
                 }
         }
-        if (current->flags & PF_FREEZE)
-                refrigerator(PF_FREEZE);
+        try_to_freeze();
         remove_wait_queue(&msp->wq, &wait);
         return msp->restart;
 }
diff --git a/drivers/media/video/video-buf-dvb.c b/drivers/media/video/video-buf-dvb.c
index 5f870075b55e..15f5bb486963 100644
--- a/drivers/media/video/video-buf-dvb.c
+++ b/drivers/media/video/video-buf-dvb.c
@@ -62,8 +62,7 @@ static int videobuf_dvb_thread(void *data)
                         break;
                 if (kthread_should_stop())
                         break;
-                if (current->flags & PF_FREEZE)
-                        refrigerator(PF_FREEZE);
+                try_to_freeze();
 
                 /* feed buffer data to demux */
                 if (buf->state == STATE_DONE)
diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c
index 047202c4d9a8..5a4a08a7c951 100644
--- a/drivers/net/8139too.c
+++ b/drivers/net/8139too.c
@@ -1606,7 +1606,7 @@ static int rtl8139_thread (void *data)
                 do {
                         timeout = interruptible_sleep_on_timeout (&tp->thr_wait, timeout);
                         /* make swsusp happy with our thread */
-                        try_to_freeze(PF_FREEZE);
+                        try_to_freeze();
                 } while (!signal_pending (current) && (timeout > 0));
 
                 if (signal_pending (current)) {
diff --git a/drivers/net/irda/sir_kthread.c b/drivers/net/irda/sir_kthread.c
index 18cea1099530..c65054364bca 100644
--- a/drivers/net/irda/sir_kthread.c
+++ b/drivers/net/irda/sir_kthread.c
@@ -135,8 +135,7 @@ static int irda_thread(void *startup)
                 remove_wait_queue(&irda_rq_queue.kick, &wait);
 
                 /* make swsusp happy with our thread */
-                if (current->flags & PF_FREEZE)
-                        refrigerator(PF_FREEZE);
+                try_to_freeze();
 
                 run_irda_queue();
         }
diff --git a/drivers/net/irda/stir4200.c b/drivers/net/irda/stir4200.c
index 66f488c13717..15f207323d97 100644
--- a/drivers/net/irda/stir4200.c
+++ b/drivers/net/irda/stir4200.c
@@ -763,7 +763,7 @@ static int stir_transmit_thread(void *arg)
         {
 #ifdef CONFIG_PM
                 /* if suspending, then power off and wait */
-                if (unlikely(current->flags & PF_FREEZE)) {
+                if (unlikely(freezing(current))) {
                         if (stir->receiving)
                                 receive_stop(stir);
                         else
@@ -771,7 +771,7 @@ static int stir_transmit_thread(void *arg)
 
                         write_reg(stir, REG_CTRL1, CTRL1_TXPWD|CTRL1_RXPWD);
 
-                        refrigerator(PF_FREEZE);
+                        refrigerator();
 
                         if (change_speed(stir, stir->speed))
                                 break;
diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c
index fb10a2db63ad..d72e0385e4f2 100644
--- a/drivers/net/wireless/airo.c
+++ b/drivers/net/wireless/airo.c
@@ -2918,7 +2918,7 @@ static int airo_thread(void *data) {
                         flush_signals(current);
 
                 /* make swsusp happy with our thread */
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
 
                 if (test_bit(JOB_DIE, &ai->flags))
                         break;
diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index d136b3c8fac9..48e4f04530d8 100644
--- a/drivers/pcmcia/cs.c
+++ b/drivers/pcmcia/cs.c
@@ -718,7 +718,7 @@ static int pccardd(void *__skt)
                 }
 
                 schedule();
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
 
                 if (!skt->thread)
                         break;
diff --git a/drivers/pnp/pnpbios/core.c b/drivers/pnp/pnpbios/core.c
index e939c93a931c..778a324028f4 100644
--- a/drivers/pnp/pnpbios/core.c
+++ b/drivers/pnp/pnpbios/core.c
@@ -182,7 +182,7 @@ static int pnp_dock_thread(void * unused)
                 msleep_interruptible(2000);
 
                 if(signal_pending(current)) {
-                        if (try_to_freeze(PF_FREEZE))
+                        if (try_to_freeze())
                                 continue;
                         break;
                 }
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d2d648ee8640..a8d879a85d04 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2808,7 +2808,7 @@ static int hub_thread(void *__unused)
         do {
                 hub_events();
                 wait_event_interruptible(khubd_wait, !list_empty(&hub_event_list)); 
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
         } while (!signal_pending(current));
 
         pr_debug ("%s: khubd exiting\n", usbcore_name);
diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
index 037a7f163822..a9be85103d23 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -1554,8 +1554,7 @@ static int sleep_thread(struct fsg_dev *fsg)
         rc = wait_event_interruptible(fsg->thread_wqh,
                         fsg->thread_wakeup_needed);
         fsg->thread_wakeup_needed = 0;
-        if (current->flags & PF_FREEZE)
-                refrigerator(PF_FREEZE);
+        try_to_freeze();
         return (rc ? -EINTR : 0);
 }
 
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index 35c1ca6b5a8e..77e7fc258aa2 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -847,10 +847,8 @@ retry:
                 wait_event_interruptible_timeout(us->delay_wait,
                                 test_bit(US_FLIDX_DISCONNECTING, &us->flags),
                                 delay_use * HZ);
-                if (current->flags & PF_FREEZE) {
-                        refrigerator(PF_FREEZE);
+                if (try_to_freeze())
                         goto retry;
-                }
         }
 
         /* If the device is still connected, perform the scanning */
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index b460927ec32a..312cf3220f12 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -646,7 +646,7 @@ static int w1_control(void *data)
         while (!control_needs_exit || have_to_wait) {
                 have_to_wait = 0;
 
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
                 msleep_interruptible(w1_timeout * 1000);
 
                 if (signal_pending(current))
@@ -725,7 +725,7 @@ int w1_process(void *data)
         allow_signal(SIGTERM);
 
         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
-                try_to_freeze(PF_FREEZE);
+                try_to_freeze();
                 msleep_interruptible(w1_timeout * 1000);
 
                 if (signal_pending(current))