[RFC][PATCH][EXPERIMENTAL] Make kernel threads nonfreezable by default

From: Rafael J. Wysocki
Date: Sat May 26 2007 - 18:08:25 EST

Hi,

Following the "Freezing of kernel threads" discussion
(http://lkml.org/lkml/2007/5/12/162) I have created a patch that changes the
freezer's behavior with respect to kernel threads. Namely, with the patch
applied all kernel threads are nonfreezable by default (have PF_NOFREEZE set)
and the ones that want to be frozen need to call set_freezable() (which clears
PF_NOFREEZE for them) and try_to_freeze(). The other (nonfreezable) kernel
threads don't need to call try_to_freeze() any more.

I have removed try_to_freeze() from a handful of kernel threads that I think
need not be freezable, but in many cases I wasn't quite sure whether or not
it was a good idea to change the current behavior. For this reason I've added
set_freezable() to the majority of (currently freezable) kernel threads that
belong to device drivers and filesystems.

Of course, I have removed the setting of PF_NOFREEZE from the kernel threads
that are currently nonfreezable, since with the other changes in the patch it
isn't necessary any more.

This patch is on top of the "Freezer: Avoid freezing kernel threads prematurely"
patch that I posted yestarday, available at http://lkml.org/lkml/2007/5/25/199
(updated version that applies cleanly on top of 2.6.22-rc3, is available at
http://www.sisk.pl/kernel/hibernation_and_suspend/2.6.22-rc3/patches/07-freezer-avoid-freezing-kernel-threads-prematurely.patch).
It has been tested on a couple of machines and doesn't seem to break anything.

[As you can see there are quite a lot of files affected, so I didn't add all
maintainers of them to the CC list. In fact, I'm not sure how to handle
notifying them of the change, so please advise.]

Greetings,
Rafael


Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
Documentation/power/kernel_threads.txt | 54 ++++++++++++------------------
Documentation/power/swsusp.txt | 16 --------
arch/i386/kernel/apm.c | 1
arch/i386/kernel/io_apic.c | 1
drivers/block/loop.c | 7 ---
drivers/block/pktcdvd.c | 3 -
drivers/char/apm-emulation.c | 11 ------
drivers/char/hvc_console.c | 1
drivers/edac/edac_mc.c | 1
drivers/ieee1394/ieee1394_core.c | 2 -
drivers/ieee1394/nodemgr.c | 1
drivers/input/gameport/gameport.c | 1
drivers/input/serio/serio.c | 1
drivers/input/touchscreen/ucb1400_ts.c | 1
drivers/macintosh/therm_adt746x.c | 1
drivers/macintosh/windfarm_core.c | 4 +-
drivers/md/md.c | 1
drivers/media/dvb/dvb-core/dvb_frontend.c | 1
drivers/media/video/cx88/cx88-tvaudio.c | 1
drivers/media/video/msp3400-kthreads.c | 5 +-
drivers/media/video/tvaudio.c | 2 -
drivers/media/video/video-buf-dvb.c | 1
drivers/media/video/vivi.c | 1
drivers/mfd/ucb1x00-ts.c | 1
drivers/mmc/card/queue.c | 6 ---
drivers/mtd/mtd_blkdevs.c | 2 -
drivers/mtd/ubi/wl.c | 1
drivers/net/wireless/airo.c | 3 +
drivers/net/wireless/libertas/main.c | 1
drivers/pcmcia/cs.c | 1
drivers/pnp/pnpbios/core.c | 1
drivers/scsi/libsas/sas_scsi_host.c | 2 -
drivers/scsi/scsi_error.c | 2 -
drivers/usb/atm/ueagle-atm.c | 1
drivers/usb/core/hub.c | 1
drivers/usb/gadget/file_storage.c | 2 +
drivers/usb/storage/usb.c | 5 --
drivers/video/ps3fb.c | 1
drivers/w1/w1.c | 1
fs/cifs/cifsfs.c | 1
fs/cifs/connect.c | 1
fs/jffs2/background.c | 1
fs/lockd/clntproc.c | 1
fs/xfs/linux-2.6/xfs_super.c | 1
include/linux/freezer.h | 9 +++++
init/do_mounts_initrd.c | 7 +--
kernel/audit.c | 4 --
kernel/exit.c | 5 ++
kernel/fork.c | 2 -
kernel/rcutorture.c | 3 -
kernel/rtmutex-tester.c | 1
kernel/sched.c | 3 -
kernel/softirq.c | 1
kernel/softlockup.c | 1
kernel/workqueue.c | 4 +-
mm/pdflush.c | 4 --
mm/vmscan.c | 9 -----
net/bluetooth/bnep/core.c | 1
net/bluetooth/cmtp/core.c | 1
net/bluetooth/hidp/core.c | 1
net/bluetooth/rfcomm/core.c | 1
net/core/pktgen.c | 2 -
net/sunrpc/svcsock.c | 3 -
63 files changed, 78 insertions(+), 138 deletions(-)

Index: linux-2.6.22-rc3/kernel/exit.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/exit.c
+++ linux-2.6.22-rc3/kernel/exit.c
@@ -389,6 +389,11 @@ void daemonize(const char *name, ...)
* they would be locked into memory.
*/
exit_mm(current);
+ /*
+ * We don't want to have TIF_FREEZE set if the system-wide hibernation
+ * or suspend transision begins right now.
+ */
+ current->flags |= PF_NOFREEZE;

set_special_pids(1, 1);
proc_clear_tty(current);
Index: linux-2.6.22-rc3/include/linux/freezer.h
===================================================================
--- linux-2.6.22-rc3.orig/include/linux/freezer.h
+++ linux-2.6.22-rc3/include/linux/freezer.h
@@ -118,6 +118,14 @@ static inline int freezer_should_skip(st
return !!(p->flags & PF_FREEZER_SKIP);
}

+/*
+ * Tell the freezer that the current task should be frozen by it
+ */
+static inline void set_freezable(void)
+{
+ current->flags &= ~PF_NOFREEZE;
+}
+
#else
static inline int frozen(struct task_struct *p) { return 0; }
static inline int freezing(struct task_struct *p) { return 0; }
@@ -134,6 +142,7 @@ static inline int try_to_freeze(void) {
static inline void freezer_do_not_count(void) {}
static inline void freezer_count(void) {}
static inline int freezer_should_skip(struct task_struct *p) { return 0; }
+static inline void set_freezable_current(void) {}
#endif

#endif /* LINUX_FREEZER_H */
Index: linux-2.6.22-rc3/kernel/fork.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/fork.c
+++ linux-2.6.22-rc3/kernel/fork.c
@@ -920,7 +920,7 @@ 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;
if (!(clone_flags & CLONE_PTRACE))
p->ptrace = 0;
Index: linux-2.6.22-rc3/arch/i386/kernel/io_apic.c
===================================================================
--- linux-2.6.22-rc3.orig/arch/i386/kernel/io_apic.c
+++ linux-2.6.22-rc3/arch/i386/kernel/io_apic.c
@@ -669,7 +669,6 @@ static int balanced_irq(void *unused)

for ( ; ; ) {
time_remaining = schedule_timeout_interruptible(time_remaining);
- try_to_freeze();
if (time_after(jiffies,
prev_balance_time+balanced_irq_interval)) {
preempt_disable();
Index: linux-2.6.22-rc3/Documentation/power/kernel_threads.txt
===================================================================
--- linux-2.6.22-rc3.orig/Documentation/power/kernel_threads.txt
+++ linux-2.6.22-rc3/Documentation/power/kernel_threads.txt
@@ -1,13 +1,22 @@
-KERNEL THREADS
+The Freezer and Kernel Threads

-
-Freezer
-
-Upon entering a suspended state the system will freeze all
-tasks. This is done by delivering pseudosignals. This affects
-kernel threads, too. To successfully freeze a kernel thread
-the thread has to check for the pseudosignal and enter the
-refrigerator. Code to do this looks like this:
+Before entering a system-wide suspend state as well as before creating a
+hibernation snapshot image the system will freeze all tasks, which is done
+by delivering fake signals. This affects kernel threads too, but they won't be
+frozen unless they declare that they want to. For this purpose they should call
+set_freezable() that will unset the per-task flag PF_NOFREEZE for them (this
+flag is set by default for all kernel threads).
+
+For each task with PF_NOFREEZE unset the freezer sets the TIF_FREEZE flag
+whenever appropriate and sends a fake signal to it. The task should react by
+calling refrigerator(), where it will stay until the freezer allows it to
+continue. The try_to_freeze() function checks the TIF_FREEZE flag and makes
+the task enter refrigerator() if it's set, so using it is the preferred way of
+"freezing" the task.
+
+For user space processes try_to_freeze() is called from the signal-handling
+code, but the kernel threads that want to be frozen need to call it explicitly
+in suitable places. Code to do this may look like the following:

do {
hub_events();
@@ -15,26 +24,9 @@ refrigerator. Code to do this looks like
try_to_freeze();
} while (!signal_pending(current));

-from drivers/usb/core/hub.c::hub_thread()
-
-
-The Unfreezable
-
-Some kernel threads however, must not be frozen. The kernel must
-be able to finish pending IO operations and later on be able to
-write the memory image to disk. Kernel threads needed to do IO
-must stay awake. Such threads must mark themselves unfreezable
-like this:
-
- /*
- * This thread doesn't need any user-level access,
- * so get rid of all our resources.
- */
- daemonize("usb-storage");
-
- current->flags |= PF_NOFREEZE;
-
-from drivers/usb/storage/usb.c::usb_stor_control_thread()
+(from drivers/usb/core/hub.c::hub_thread()).

-Such drivers are themselves responsible for staying quiet during
-the actual snapshotting.
+If a kernel thread declares that it wants to be frozen and fails to call
+try_to_freeze() after the freezer has set TIF_FREEZE for it, the freezing of
+tasks will fail and the entire hibernation or suspend operation will be
+cancelled.
Index: linux-2.6.22-rc3/Documentation/power/swsusp.txt
===================================================================
--- linux-2.6.22-rc3.orig/Documentation/power/swsusp.txt
+++ linux-2.6.22-rc3/Documentation/power/swsusp.txt
@@ -140,22 +140,6 @@ should be sent to the mailing list avail
website, and not to the Linux Kernel Mailing List. We are working
toward merging suspend2 into the mainline kernel.

-Q: A kernel thread must voluntarily freeze itself (call 'refrigerator').
-I found some kernel threads that don't do it, and they don't freeze
-so the system can't sleep. Is this a known behavior?
-
-A: All such kernel threads need to be fixed, one by one. Select the
-place where the thread is safe to be frozen (no kernel semaphores
-should be held at that point and it must be safe to sleep there), and
-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).
-
-
Q: What is the difference between "platform" and "shutdown"?

A:
Index: linux-2.6.22-rc3/drivers/block/pktcdvd.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/block/pktcdvd.c
+++ linux-2.6.22-rc3/drivers/block/pktcdvd.c
@@ -1640,9 +1640,6 @@ static int kcdrwd(void *foobar)
residue = schedule_timeout(min_sleep_time);
VPRINTK("kcdrwd: wake up\n");

- /* make swsusp happy with our thread */
- try_to_freeze();
-
list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
if (!pkt->sleep_time)
continue;
Index: linux-2.6.22-rc3/drivers/char/hvc_console.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/char/hvc_console.c
+++ linux-2.6.22-rc3/drivers/char/hvc_console.c
@@ -679,6 +679,7 @@ int khvcd(void *unused)
int poll_mask;
struct hvc_struct *hp;

+ set_freezable();
__set_current_state(TASK_RUNNING);
do {
poll_mask = 0;
Index: linux-2.6.22-rc3/drivers/edac/edac_mc.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/edac/edac_mc.c
+++ linux-2.6.22-rc3/drivers/edac/edac_mc.c
@@ -1906,6 +1906,7 @@ static void do_edac_check(void)

static int edac_kernel_thread(void *arg)
{
+ set_freezable();
while (!kthread_should_stop()) {
do_edac_check();

Index: linux-2.6.22-rc3/drivers/ieee1394/nodemgr.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/ieee1394/nodemgr.c
+++ linux-2.6.22-rc3/drivers/ieee1394/nodemgr.c
@@ -1664,6 +1664,7 @@ static int nodemgr_host_thread(void *__h
unsigned int g, generation = 0;
int i, reset_cycles = 0;

+ set_freezable();
/* Setup our device-model entries */
nodemgr_create_host_dev_files(host);

Index: linux-2.6.22-rc3/drivers/input/gameport/gameport.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/input/gameport/gameport.c
+++ linux-2.6.22-rc3/drivers/input/gameport/gameport.c
@@ -445,6 +445,7 @@ static struct gameport *gameport_get_pen

static int gameport_thread(void *nothing)
{
+ set_freezable();
do {
gameport_handle_event();
wait_event_interruptible(gameport_wait,
Index: linux-2.6.22-rc3/drivers/input/serio/serio.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/input/serio/serio.c
+++ linux-2.6.22-rc3/drivers/input/serio/serio.c
@@ -384,6 +384,7 @@ static struct serio *serio_get_pending_c

static int serio_thread(void *nothing)
{
+ set_freezable();
do {
serio_handle_event();
wait_event_interruptible(serio_wait,
Index: linux-2.6.22-rc3/drivers/macintosh/therm_adt746x.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/macintosh/therm_adt746x.c
+++ linux-2.6.22-rc3/drivers/macintosh/therm_adt746x.c
@@ -336,7 +336,6 @@ static int monitor_task(void *arg)
struct thermostat* th = arg;

while(!kthread_should_stop()) {
- try_to_freeze();
msleep_interruptible(2000);

#ifndef DEBUG
Index: linux-2.6.22-rc3/drivers/macintosh/windfarm_core.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/macintosh/windfarm_core.c
+++ linux-2.6.22-rc3/drivers/macintosh/windfarm_core.c
@@ -115,8 +115,8 @@ static int wf_thread_func(void *data)
if (delay <= HZ)
schedule_timeout_interruptible(delay);

- /* there should be no non-suspend signal, but oh well */
- if (signal_pending(current) && !try_to_freeze()) {
+ /* there should be no signal, but oh well */
+ if (signal_pending(current)) {
printk(KERN_WARNING "windfarm: thread got sigl !\n");
break;
}
Index: linux-2.6.22-rc3/drivers/media/dvb/dvb-core/dvb_frontend.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ linux-2.6.22-rc3/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -523,6 +523,7 @@ static int dvb_frontend_thread(void *dat

dvb_frontend_init(fe);

+ set_freezable();
while (1) {
up(&fepriv->sem); /* is locked when we enter the thread... */
restart:
Index: linux-2.6.22-rc3/drivers/media/video/cx88/cx88-tvaudio.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/media/video/cx88/cx88-tvaudio.c
+++ linux-2.6.22-rc3/drivers/media/video/cx88/cx88-tvaudio.c
@@ -906,6 +906,7 @@ int cx88_audio_thread(void *data)
u32 mode = 0;

dprintk("cx88: tvaudio thread started\n");
+ set_freezable();
for (;;) {
msleep_interruptible(1000);
if (kthread_should_stop())
Index: linux-2.6.22-rc3/drivers/media/video/msp3400-kthreads.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/media/video/msp3400-kthreads.c
+++ linux-2.6.22-rc3/drivers/media/video/msp3400-kthreads.c
@@ -468,6 +468,7 @@ int msp3400c_thread(void *data)


v4l_dbg(1, msp_debug, client, "msp3400 daemon started\n");
+ set_freezable();
for (;;) {
v4l_dbg(2, msp_debug, client, "msp3400 thread: sleep\n");
msp_sleep(state, -1);
@@ -646,7 +647,7 @@ int msp3410d_thread(void *data)
int val, i, std, count;

v4l_dbg(1, msp_debug, client, "msp3410 daemon started\n");
-
+ set_freezable();
for (;;) {
v4l_dbg(2, msp_debug, client, "msp3410 thread: sleep\n");
msp_sleep(state,-1);
@@ -940,7 +941,7 @@ int msp34xxg_thread(void *data)
int val, i;

v4l_dbg(1, msp_debug, client, "msp34xxg daemon started\n");
-
+ set_freezable();
for (;;) {
v4l_dbg(2, msp_debug, client, "msp34xxg thread: sleep\n");
msp_sleep(state, -1);
Index: linux-2.6.22-rc3/drivers/media/video/tvaudio.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/media/video/tvaudio.c
+++ linux-2.6.22-rc3/drivers/media/video/tvaudio.c
@@ -271,7 +271,7 @@ static int chip_thread(void *data)
struct CHIPDESC *desc = chiplist + chip->type;

v4l_dbg(1, debug, &chip->c, "%s: thread started\n", chip->c.name);
-
+ set_freezable();
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop())
Index: linux-2.6.22-rc3/drivers/media/video/video-buf-dvb.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/media/video/video-buf-dvb.c
+++ linux-2.6.22-rc3/drivers/media/video/video-buf-dvb.c
@@ -47,6 +47,7 @@ static int videobuf_dvb_thread(void *dat
int err;

dprintk("dvb thread started\n");
+ set_freezable();
videobuf_read_start(&dvb->dvbq);

for (;;) {
Index: linux-2.6.22-rc3/drivers/media/video/vivi.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/media/video/vivi.c
+++ linux-2.6.22-rc3/drivers/media/video/vivi.c
@@ -563,7 +563,6 @@ static void vivi_sleep(struct vivi_dmaqu
}

remove_wait_queue(&dma_q->wq, &wait);
- try_to_freeze();
}

static int vivi_thread(void *data)
Index: linux-2.6.22-rc3/drivers/mfd/ucb1x00-ts.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/mfd/ucb1x00-ts.c
+++ linux-2.6.22-rc3/drivers/mfd/ucb1x00-ts.c
@@ -209,6 +209,7 @@ static int ucb1x00_thread(void *_ts)
DECLARE_WAITQUEUE(wait, tsk);
int valid = 0;

+ set_freezable();
add_wait_queue(&ts->irq_wait, &wait);
while (!kthread_should_stop()) {
unsigned int x, y, p;
Index: linux-2.6.22-rc3/drivers/mtd/ubi/wl.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/mtd/ubi/wl.c
+++ linux-2.6.22-rc3/drivers/mtd/ubi/wl.c
@@ -1346,6 +1346,7 @@ static int ubi_thread(void *u)
ubi_msg("background thread \"%s\" started, PID %d",
ubi->bgt_name, current->pid);

+ set_freezable();
for (;;) {
int err;

Index: linux-2.6.22-rc3/drivers/net/wireless/airo.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/net/wireless/airo.c
+++ linux-2.6.22-rc3/drivers/net/wireless/airo.c
@@ -3078,7 +3078,8 @@ static int airo_thread(void *data) {
struct net_device *dev = data;
struct airo_info *ai = dev->priv;
int locked;
-
+
+ set_freezable();
while(1) {
/* make swsusp happy with our thread */
try_to_freeze();
Index: linux-2.6.22-rc3/drivers/net/wireless/libertas/main.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/net/wireless/libertas/main.c
+++ linux-2.6.22-rc3/drivers/net/wireless/libertas/main.c
@@ -718,6 +718,7 @@ static int wlan_service_main_thread(void

init_waitqueue_entry(&wait, current);

+ set_freezable();
for (;;) {
lbs_pr_debug(1, "main-thread 111: intcounter=%d "
"currenttxskb=%p dnld_sent=%d\n",
Index: linux-2.6.22-rc3/drivers/pcmcia/cs.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/pcmcia/cs.c
+++ linux-2.6.22-rc3/drivers/pcmcia/cs.c
@@ -651,6 +651,7 @@ static int pccardd(void *__skt)
add_wait_queue(&skt->thread_wait, &wait);
complete(&skt->thread_done);

+ set_freezable();
for (;;) {
unsigned long flags;
unsigned int events;
Index: linux-2.6.22-rc3/drivers/pnp/pnpbios/core.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/pnp/pnpbios/core.c
+++ linux-2.6.22-rc3/drivers/pnp/pnpbios/core.c
@@ -160,6 +160,7 @@ static int pnp_dock_thread(void * unused
{
static struct pnp_docking_station_info now;
int docked = -1, d = 0;
+ set_freezable();
while (!unloading)
{
int status;
Index: linux-2.6.22-rc3/drivers/input/touchscreen/ucb1400_ts.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/input/touchscreen/ucb1400_ts.c
+++ linux-2.6.22-rc3/drivers/input/touchscreen/ucb1400_ts.c
@@ -336,7 +336,6 @@ static int ucb1400_ts_thread(void *_ucb)
wait_event_interruptible_timeout(ucb->ts_wait,
ucb->irq_pending || ucb->ts_restart || kthread_should_stop(),
timeout);
- try_to_freeze();
}

/* Send the "pen off" if we are stopping with the pen still active */
Index: linux-2.6.22-rc3/drivers/usb/atm/ueagle-atm.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/usb/atm/ueagle-atm.c
+++ linux-2.6.22-rc3/drivers/usb/atm/ueagle-atm.c
@@ -1168,6 +1168,7 @@ static int uea_kthread(void *data)
struct uea_softc *sc = data;
int ret = -EAGAIN;

+ set_freezable();
uea_enters(INS_TO_USBDEV(sc));
while (!kthread_should_stop()) {
if (ret < 0 || sc->reset)
Index: linux-2.6.22-rc3/drivers/usb/core/hub.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/usb/core/hub.c
+++ linux-2.6.22-rc3/drivers/usb/core/hub.c
@@ -2799,6 +2799,7 @@ loop:

static int hub_thread(void *__unused)
{
+ set_freezable();
do {
hub_events();
wait_event_interruptible(khubd_wait,
Index: linux-2.6.22-rc3/drivers/usb/gadget/file_storage.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/usb/gadget/file_storage.c
+++ linux-2.6.22-rc3/drivers/usb/gadget/file_storage.c
@@ -3435,6 +3435,8 @@ static int fsg_main_thread(void *fsg_)
sigmask(SIGTERM) | sigmask(SIGKILL) |
sigmask(SIGUSR1));
sigprocmask(SIG_SETMASK, &fsg->thread_signal_mask, NULL);
+ /* Allow the thread to be frozen */
+ set_freezable();

/* Arrange for userspace references to be interpreted as kernel
* pointers. That way we can pass a kernel pointer to a routine
Index: linux-2.6.22-rc3/drivers/usb/storage/usb.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/usb/storage/usb.c
+++ linux-2.6.22-rc3/drivers/usb/storage/usb.c
@@ -301,8 +301,6 @@ 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;
-
for(;;) {
US_DEBUGP("*** thread sleeping.\n");
if(down_interruptible(&us->sema))
@@ -913,12 +911,9 @@ static int usb_stor_scan_thread(void * _
if (delay_use > 0) {
printk(KERN_DEBUG "usb-storage: waiting for device "
"to settle before scanning\n");
-retry:
wait_event_interruptible_timeout(us->delay_wait,
test_bit(US_FLIDX_DISCONNECTING, &us->flags),
delay_use * HZ);
- if (try_to_freeze())
- goto retry;
}

/* If the device is still connected, perform the scanning */
Index: linux-2.6.22-rc3/drivers/video/ps3fb.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/video/ps3fb.c
+++ linux-2.6.22-rc3/drivers/video/ps3fb.c
@@ -812,6 +812,7 @@ static int ps3fb_ioctl(struct fb_info *i

static int ps3fbd(void *arg)
{
+ set_freezable();
while (!kthread_should_stop()) {
try_to_freeze();
set_current_state(TASK_INTERRUPTIBLE);
Index: linux-2.6.22-rc3/drivers/w1/w1.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/w1/w1.c
+++ linux-2.6.22-rc3/drivers/w1/w1.c
@@ -801,6 +801,7 @@ static int w1_control(void *data)
struct w1_master *dev, *n;
int have_to_wait = 0;

+ set_freezable();
while (!kthread_should_stop() || have_to_wait) {
have_to_wait = 0;

Index: linux-2.6.22-rc3/fs/cifs/cifsfs.c
===================================================================
--- linux-2.6.22-rc3.orig/fs/cifs/cifsfs.c
+++ linux-2.6.22-rc3/fs/cifs/cifsfs.c
@@ -849,6 +849,7 @@ static int cifs_oplock_thread(void * dum
__u16 netfid;
int rc;

+ set_freezable();
do {
if (try_to_freeze())
continue;
Index: linux-2.6.22-rc3/fs/cifs/connect.c
===================================================================
--- linux-2.6.22-rc3.orig/fs/cifs/connect.c
+++ linux-2.6.22-rc3/fs/cifs/connect.c
@@ -363,6 +363,7 @@ cifs_demultiplex_thread(struct TCP_Serve
GFP_KERNEL);
}

+ set_freezable();
while (!kthread_should_stop()) {
if (try_to_freeze())
continue;
Index: linux-2.6.22-rc3/fs/jffs2/background.c
===================================================================
--- linux-2.6.22-rc3.orig/fs/jffs2/background.c
+++ linux-2.6.22-rc3/fs/jffs2/background.c
@@ -81,6 +81,7 @@ static int jffs2_garbage_collect_thread(

set_user_nice(current, 10);

+ set_freezable();
for (;;) {
allow_signal(SIGHUP);

Index: linux-2.6.22-rc3/fs/lockd/clntproc.c
===================================================================
--- linux-2.6.22-rc3.orig/fs/lockd/clntproc.c
+++ linux-2.6.22-rc3/fs/lockd/clntproc.c
@@ -268,7 +268,6 @@ static int nlm_wait_on_grace(wait_queue_
prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
if (!signalled ()) {
schedule_timeout(NLMCLNT_GRACE_WAIT);
- try_to_freeze();
if (!signalled ())
status = 0;
}
Index: linux-2.6.22-rc3/fs/xfs/linux-2.6/xfs_super.c
===================================================================
--- linux-2.6.22-rc3.orig/fs/xfs/linux-2.6/xfs_super.c
+++ linux-2.6.22-rc3/fs/xfs/linux-2.6/xfs_super.c
@@ -561,6 +561,7 @@ xfssyncd(
bhv_vfs_sync_work_t *work, *n;
LIST_HEAD (tmp);

+ set_freezable();
timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
for (;;) {
timeleft = schedule_timeout_interruptible(timeleft);
Index: linux-2.6.22-rc3/init/do_mounts_initrd.c
===================================================================
--- linux-2.6.22-rc3.orig/init/do_mounts_initrd.c
+++ linux-2.6.22-rc3/init/do_mounts_initrd.c
@@ -56,12 +56,9 @@ static void __init handle_initrd(void)
sys_chroot(".");

pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
- if (pid > 0) {
- while (pid != sys_wait4(-1, NULL, 0, NULL)) {
- try_to_freeze();
+ if (pid > 0)
+ while (pid != sys_wait4(-1, NULL, 0, NULL))
yield();
- }
- }

/* move initrd to rootfs' /old */
sys_fchdir(old_fd);
Index: linux-2.6.22-rc3/kernel/audit.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/audit.c
+++ linux-2.6.22-rc3/kernel/audit.c
@@ -411,10 +411,8 @@ static int kauditd_thread(void *dummy)
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&kauditd_wait, &wait);

- if (!skb_queue_len(&audit_skb_queue)) {
- try_to_freeze();
+ if (!skb_queue_len(&audit_skb_queue))
schedule();
- }

__set_current_state(TASK_RUNNING);
remove_wait_queue(&kauditd_wait, &wait);
Index: linux-2.6.22-rc3/kernel/rtmutex-tester.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/rtmutex-tester.c
+++ linux-2.6.22-rc3/kernel/rtmutex-tester.c
@@ -275,7 +275,6 @@ static int test_func(void *data)

/* Wait for the next command to be executed */
schedule();
- try_to_freeze();

if (signal_pending(current))
flush_signals(current);
Index: linux-2.6.22-rc3/kernel/sched.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/sched.c
+++ linux-2.6.22-rc3/kernel/sched.c
@@ -5161,8 +5161,6 @@ static int migration_thread(void *data)
struct migration_req *req;
struct list_head *head;

- try_to_freeze();
-
spin_lock_irq(&rq->lock);

if (cpu_is_offline(cpu)) {
@@ -5396,7 +5394,6 @@ 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;
kthread_bind(p, cpu);
/* Must be high prio: stop_machine expects to yield to it. */
rq = task_rq_lock(p, &flags);
Index: linux-2.6.22-rc3/kernel/workqueue.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/workqueue.c
+++ linux-2.6.22-rc3/kernel/workqueue.c
@@ -282,8 +282,8 @@ static int worker_thread(void *__cwq)
struct cpu_workqueue_struct *cwq = __cwq;
DEFINE_WAIT(wait);

- if (!cwq->wq->freezeable)
- current->flags |= PF_NOFREEZE;
+ if (cwq->wq->freezeable)
+ set_freezable();

set_user_nice(current, -5);

Index: linux-2.6.22-rc3/mm/pdflush.c
===================================================================
--- linux-2.6.22-rc3.orig/mm/pdflush.c
+++ linux-2.6.22-rc3/mm/pdflush.c
@@ -106,13 +106,11 @@ static int __pdflush(struct pdflush_work
my_work->when_i_went_to_sleep = jiffies;
spin_unlock_irq(&pdflush_lock);
schedule();
- try_to_freeze();
spin_lock_irq(&pdflush_lock);
if (!list_empty(&my_work->list)) {
/*
* Someone woke us up, but without removing our control
- * structure from the global list. swsusp will do this
- * in try_to_freeze()->refrigerator(). Handle it.
+ * structure from the global list. Handle it.
*/
my_work->fn = NULL;
continue;
Index: linux-2.6.22-rc3/mm/vmscan.c
===================================================================
--- linux-2.6.22-rc3.orig/mm/vmscan.c
+++ linux-2.6.22-rc3/mm/vmscan.c
@@ -1264,8 +1264,6 @@ out:
if (!all_zones_ok) {
cond_resched();

- try_to_freeze();
-
goto loop_again;
}

@@ -1336,12 +1334,7 @@ static int kswapd(void *p)
}
finish_wait(&pgdat->kswapd_wait, &wait);

- if (!try_to_freeze()) {
- /* We can speed up thawing tasks if we don't call
- * balance_pgdat after returning from the refrigerator
- */
- balance_pgdat(pgdat, order);
- }
+ balance_pgdat(pgdat, order);
}
return 0;
}
Index: linux-2.6.22-rc3/net/core/pktgen.c
===================================================================
--- linux-2.6.22-rc3.orig/net/core/pktgen.c
+++ linux-2.6.22-rc3/net/core/pktgen.c
@@ -3326,8 +3326,6 @@ static int pktgen_thread_worker(void *ar
t->control &= ~(T_REMDEV);
}

- try_to_freeze();
-
set_current_state(TASK_INTERRUPTIBLE);
}

Index: linux-2.6.22-rc3/net/sunrpc/svcsock.c
===================================================================
--- linux-2.6.22-rc3.orig/net/sunrpc/svcsock.c
+++ linux-2.6.22-rc3/net/sunrpc/svcsock.c
@@ -1436,7 +1436,6 @@ svc_recv(struct svc_rqst *rqstp, long ti
arg->len = (pages-1)*PAGE_SIZE;
arg->tail[0].iov_len = 0;

- try_to_freeze();
cond_resched();
if (signalled())
return -EINTR;
@@ -1461,8 +1460,6 @@ svc_recv(struct svc_rqst *rqstp, long ti

schedule_timeout(timeout);

- try_to_freeze();
-
spin_lock_bh(&pool->sp_lock);
remove_wait_queue(&rqstp->rq_wait, &wait);

Index: linux-2.6.22-rc3/arch/i386/kernel/apm.c
===================================================================
--- linux-2.6.22-rc3.orig/arch/i386/kernel/apm.c
+++ linux-2.6.22-rc3/arch/i386/kernel/apm.c
@@ -2309,7 +2309,6 @@ static int __init apm_init(void)
remove_proc_entry("apm", NULL);
return err;
}
- kapmd_task->flags |= PF_NOFREEZE;
wake_up_process(kapmd_task);

if (num_online_cpus() > 1 && !smp ) {
Index: linux-2.6.22-rc3/drivers/block/loop.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/block/loop.c
+++ linux-2.6.22-rc3/drivers/block/loop.c
@@ -576,13 +576,6 @@ static int loop_thread(void *data)
struct loop_device *lo = data;
struct bio *bio;

- /*
- * loop can be used in an encrypted device,
- * hence, it mustn't be stopped at all
- * because it could be indirectly used during suspension
- */
- current->flags |= PF_NOFREEZE;
-
set_user_nice(current, -20);

while (!kthread_should_stop() || lo->lo_bio) {
Index: linux-2.6.22-rc3/drivers/char/apm-emulation.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/char/apm-emulation.c
+++ linux-2.6.22-rc3/drivers/char/apm-emulation.c
@@ -329,13 +329,8 @@ apm_ioctl(struct inode * inode, struct f
/*
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
- *
- * Note: we need to ensure that the PM subsystem does
- * not kick us out of the wait when it suspends the
- * threads.
*/
flags = current->flags;
- current->flags |= PF_NOFREEZE;

wait_event(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
@@ -365,13 +360,8 @@ apm_ioctl(struct inode * inode, struct f
/*
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
- *
- * Note: we need to ensure that the PM subsystem does
- * not kick us out of the wait when it suspends the
- * threads.
*/
flags = current->flags;
- current->flags |= PF_NOFREEZE;

wait_event_interruptible(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
@@ -598,7 +588,6 @@ static int __init apm_init(void)
kapmd_tsk = NULL;
return ret;
}
- kapmd_tsk->flags |= PF_NOFREEZE;
wake_up_process(kapmd_tsk);

#ifdef CONFIG_PROC_FS
Index: linux-2.6.22-rc3/drivers/ieee1394/ieee1394_core.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/ieee1394/ieee1394_core.c
+++ linux-2.6.22-rc3/drivers/ieee1394/ieee1394_core.c
@@ -1133,8 +1133,6 @@ static int hpsbpkt_thread(void *__hi)
struct list_head tmp;
int may_schedule;

- current->flags |= PF_NOFREEZE;
-
while (!kthread_should_stop()) {

INIT_LIST_HEAD(&tmp);
Index: linux-2.6.22-rc3/drivers/md/md.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/md/md.c
+++ linux-2.6.22-rc3/drivers/md/md.c
@@ -4642,7 +4642,6 @@ static int md_thread(void * arg)
* many dirty RAID5 blocks.
*/

- current->flags |= PF_NOFREEZE;
allow_signal(SIGKILL);
while (!kthread_should_stop()) {

Index: linux-2.6.22-rc3/drivers/mmc/card/queue.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/mmc/card/queue.c
+++ linux-2.6.22-rc3/drivers/mmc/card/queue.c
@@ -42,11 +42,7 @@ static int mmc_queue_thread(void *d)
struct mmc_queue *mq = d;
struct request_queue *q = mq->queue;

- /*
- * 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;

down(&mq->thread_sem);
do {
Index: linux-2.6.22-rc3/drivers/mtd/mtd_blkdevs.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/mtd/mtd_blkdevs.c
+++ linux-2.6.22-rc3/drivers/mtd/mtd_blkdevs.c
@@ -80,7 +80,7 @@ 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;

spin_lock_irq(rq->queue_lock);
while (!kthread_should_stop()) {
Index: linux-2.6.22-rc3/drivers/scsi/libsas/sas_scsi_host.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/scsi/libsas/sas_scsi_host.c
+++ linux-2.6.22-rc3/drivers/scsi/libsas/sas_scsi_host.c
@@ -868,8 +868,6 @@ static int sas_queue_thread(void *_sas_h
{
struct sas_ha_struct *sas_ha = _sas_ha;

- current->flags |= PF_NOFREEZE;
-
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
Index: linux-2.6.22-rc3/drivers/scsi/scsi_error.c
===================================================================
--- linux-2.6.22-rc3.orig/drivers/scsi/scsi_error.c
+++ linux-2.6.22-rc3/drivers/scsi/scsi_error.c
@@ -1536,8 +1536,6 @@ int scsi_error_handler(void *data)
{
struct Scsi_Host *shost = data;

- current->flags |= PF_NOFREEZE;
-
/*
* We use TASK_INTERRUPTIBLE so that the thread is not
* counted against the load average as a running process.
Index: linux-2.6.22-rc3/kernel/rcutorture.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/rcutorture.c
+++ linux-2.6.22-rc3/kernel/rcutorture.c
@@ -518,7 +518,6 @@ rcu_torture_writer(void *arg)

VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;

do {
schedule_timeout_uninterruptible(1);
@@ -558,7 +557,6 @@ rcu_torture_fakewriter(void *arg)

VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;

do {
schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
@@ -589,7 +587,6 @@ rcu_torture_reader(void *arg)

VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;

do {
idx = cur_ops->readlock();
Index: linux-2.6.22-rc3/kernel/softirq.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/softirq.c
+++ linux-2.6.22-rc3/kernel/softirq.c
@@ -489,7 +489,6 @@ void __init softirq_init(void)
static int ksoftirqd(void * __bind_cpu)
{
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;

set_current_state(TASK_INTERRUPTIBLE);

Index: linux-2.6.22-rc3/kernel/softlockup.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/softlockup.c
+++ linux-2.6.22-rc3/kernel/softlockup.c
@@ -116,7 +116,6 @@ 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;

/* initialize timestamp */
touch_softlockup_watchdog();
Index: linux-2.6.22-rc3/net/bluetooth/bnep/core.c
===================================================================
--- linux-2.6.22-rc3.orig/net/bluetooth/bnep/core.c
+++ linux-2.6.22-rc3/net/bluetooth/bnep/core.c
@@ -474,7 +474,6 @@ static int bnep_session(void *arg)

daemonize("kbnepd %s", dev->name);
set_user_nice(current, -15);
- current->flags |= PF_NOFREEZE;

init_waitqueue_entry(&wait, current);
add_wait_queue(sk->sk_sleep, &wait);
Index: linux-2.6.22-rc3/net/bluetooth/cmtp/core.c
===================================================================
--- linux-2.6.22-rc3.orig/net/bluetooth/cmtp/core.c
+++ linux-2.6.22-rc3/net/bluetooth/cmtp/core.c
@@ -287,7 +287,6 @@ static int cmtp_session(void *arg)

daemonize("kcmtpd_ctr_%d", session->num);
set_user_nice(current, -15);
- current->flags |= PF_NOFREEZE;

init_waitqueue_entry(&wait, current);
add_wait_queue(sk->sk_sleep, &wait);
Index: linux-2.6.22-rc3/net/bluetooth/hidp/core.c
===================================================================
--- linux-2.6.22-rc3.orig/net/bluetooth/hidp/core.c
+++ linux-2.6.22-rc3/net/bluetooth/hidp/core.c
@@ -547,7 +547,6 @@ static int hidp_session(void *arg)

daemonize("khidpd_%04x%04x", vendor, product);
set_user_nice(current, -15);
- current->flags |= PF_NOFREEZE;

init_waitqueue_entry(&ctrl_wait, current);
init_waitqueue_entry(&intr_wait, current);
Index: linux-2.6.22-rc3/net/bluetooth/rfcomm/core.c
===================================================================
--- linux-2.6.22-rc3.orig/net/bluetooth/rfcomm/core.c
+++ linux-2.6.22-rc3/net/bluetooth/rfcomm/core.c
@@ -1940,7 +1940,6 @@ static int rfcomm_run(void *unused)

daemonize("krfcommd");
set_user_nice(current, -10);
- current->flags |= PF_NOFREEZE;

BT_DBG("");

-
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