diff options
65 files changed, 256 insertions, 113 deletions
diff --git a/Documentation/power/freezing-of-tasks.txt b/Documentation/power/freezing-of-tasks.txt new file mode 100644 index 00000000000..af1a282c71a --- /dev/null +++ b/Documentation/power/freezing-of-tasks.txt @@ -0,0 +1,160 @@ +Freezing of tasks + (C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL + +I. What is the freezing of tasks? + +The freezing of tasks is a mechanism by which user space processes and some +kernel threads are controlled during hibernation or system-wide suspend (on some +architectures). + +II. How does it work? + +There are four per-task flags used for that, PF_NOFREEZE, PF_FROZEN, TIF_FREEZE +and PF_FREEZER_SKIP (the last one is auxiliary). The tasks that have +PF_NOFREEZE unset (all user space processes and some kernel threads) are +regarded as 'freezable' and treated in a special way before the system enters a +suspend state as well as before a hibernation image is created (in what follows +we only consider hibernation, but the description also applies to suspend). + +Namely, as the first step of the hibernation procedure the function +freeze_processes() (defined in kernel/power/process.c) is called. It executes +try_to_freeze_tasks() that sets TIF_FREEZE for all of the freezable tasks and +sends a fake signal to each of them. A task that receives such a signal and has +TIF_FREEZE set, should react to it by calling the refrigerator() function +(defined in kernel/power/process.c), which sets the task's PF_FROZEN flag, +changes its state to TASK_UNINTERRUPTIBLE and makes it loop until PF_FROZEN is +cleared for it. Then, we say that the task is 'frozen' and therefore the set of +functions handling this mechanism is called 'the freezer' (these functions are +defined in kernel/power/process.c and include/linux/freezer.h). User space +processes are generally frozen before kernel threads. + +It is not recommended to call refrigerator() directly. Instead, it is +recommended to use the try_to_freeze() function (defined in +include/linux/freezer.h), that checks the task's TIF_FREEZE flag and makes the +task enter refrigerator() if the flag is set. + +For user space processes try_to_freeze() is called automatically from the +signal-handling code, but the freezable kernel threads need to call it +explicitly in suitable places. The code to do this may look like the following: + + do { + hub_events(); + wait_event_interruptible(khubd_wait, + !list_empty(&hub_event_list)); + try_to_freeze(); + } while (!signal_pending(current)); + +(from drivers/usb/core/hub.c::hub_thread()). + +If a freezable kernel thread 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 operation will be cancelled. For this reason, freezable kernel +threads must call try_to_freeze() somewhere. + +After the system memory state has been restored from a hibernation image and +devices have been reinitialized, the function thaw_processes() is called in +order to clear the PF_FROZEN flag for each frozen task. Then, the tasks that +have been frozen leave refrigerator() and continue running. + +III. Which kernel threads are freezable? + +Kernel threads are not freezable by default. However, a kernel thread may clear +PF_NOFREEZE for itself by calling set_freezable() (the resetting of PF_NOFREEZE +directly is strongly discouraged). From this point it is regarded as freezable +and must call try_to_freeze() in a suitable place. + +IV. Why do we do that? + +Generally speaking, there is a couple of reasons to use the freezing of tasks: + +1. The principal reason is to prevent filesystems from being damaged after +hibernation. At the moment we have no simple means of checkpointing +filesystems, so if there are any modifications made to filesystem data and/or +metadata on disks, we cannot bring them back to the state from before the +modifications. At the same time each hibernation image contains some +filesystem-related information that must be consistent with the state of the +on-disk data and metadata after the system memory state has been restored from +the image (otherwise the filesystems will be damaged in a nasty way, usually +making them almost impossible to repair). We therefore freeze tasks that might +cause the on-disk filesystems' data and metadata to be modified after the +hibernation image has been created and before the system is finally powered off. +The majority of these are user space processes, but if any of the kernel threads +may cause something like this to happen, they have to be freezable. + +2. The second reason is to prevent user space processes and some kernel threads +from interfering with the suspending and resuming of devices. A user space +process running on a second CPU while we are suspending devices may, for +example, be troublesome and without the freezing of tasks we would need some +safeguards against race conditions that might occur in such a case. + +Although Linus Torvalds doesn't like the freezing of tasks, he said this in one +of the discussions on LKML (http://lkml.org/lkml/2007/4/27/608): + +"RJW:> Why we freeze tasks at all or why we freeze kernel threads? + +Linus: In many ways, 'at all'. + +I _do_ realize the IO request queue issues, and that we cannot actually do +s2ram with some devices in the middle of a DMA. So we want to be able to +avoid *that*, there's no question about that. And I suspect that stopping +user threads and then waiting for a sync is practically one of the easier +ways to do so. + +So in practice, the 'at all' may become a 'why freeze kernel threads?' and +freezing user threads I don't find really objectionable." + +Still, there are kernel threads that may want to be freezable. For example, if +a kernel that belongs to a device driver accesses the device directly, it in +principle needs to know when the device is suspended, so that it doesn't try to +access it at that time. However, if the kernel thread is freezable, it will be +frozen before the driver's .suspend() callback is executed and it will be +thawed after the driver's .resume() callback has run, so it won't be accessing +the device while it's suspended. + +3. Another reason for freezing tasks is to prevent user space processes from +realizing that hibernation (or suspend) operation takes place. Ideally, user +space processes should not notice that such a system-wide operation has occurred +and should continue running without any problems after the restore (or resume +from suspend). Unfortunately, in the most general case this is quite difficult +to achieve without the freezing of tasks. Consider, for example, a process +that depends on all CPUs being online while it's running. Since we need to +disable nonboot CPUs during the hibernation, if this process is not frozen, it +may notice that the number of CPUs has changed and may start to work incorrectly +because of that. + +V. Are there any problems related to the freezing of tasks? + +Yes, there are. + +First of all, the freezing of kernel threads may be tricky if they depend one +on another. For example, if kernel thread A waits for a completion (in the +TASK_UNINTERRUPTIBLE state) that needs to be done by freezable kernel thread B +and B is frozen in the meantime, then A will be blocked until B is thawed, which +may be undesirable. That's why kernel threads are not freezable by default. + +Second, there are the following two problems related to the freezing of user +space processes: +1. Putting processes into an uninterruptible sleep distorts the load average. +2. Now that we have FUSE, plus the framework for doing device drivers in +userspace, it gets even more complicated because some userspace processes are +now doing the sorts of things that kernel threads do +(https://lists.linux-foundation.org/pipermail/linux-pm/2007-May/012309.html). + +The problem 1. seems to be fixable, although it hasn't been fixed so far. The +other one is more serious, but it seems that we can work around it by using +hibernation (and suspend) notifiers (in that case, though, we won't be able to +avoid the realization by the user space processes that the hibernation is taking +place). + +There are also problems that the freezing of tasks tends to expose, although +they are not directly related to it. For example, if request_firmware() is +called from a device driver's .resume() routine, it will timeout and eventually +fail, because the user land process that should respond to the request is frozen +at this point. So, seemingly, the failure is due to the freezing of tasks. +Suppose, however, that the firmware file is located on a filesystem accessible +only through another device that hasn't been resumed yet. In that case, +request_firmware() will fail regardless of whether or not the freezing of tasks +is used. Consequently, the problem is not really related to the freezing of +tasks, since it generally exists anyway. [The solution to this particular +problem is to keep the firmware in memory after it's loaded for the first time +and upload if from memory to the device whenever necessary.] diff --git a/Documentation/power/kernel_threads.txt b/Documentation/power/kernel_threads.txt deleted file mode 100644 index fb57784986b..00000000000 --- a/Documentation/power/kernel_threads.txt +++ /dev/null @@ -1,40 +0,0 @@ -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: - - do { - hub_events(); - wait_event_interruptible(khubd_wait, !list_empty(&hub_event_list)); - 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() - -Such drivers are themselves responsible for staying quiet during -the actual snapshotting. diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt index 152b510d1bb..aea7e920966 100644 --- a/Documentation/power/swsusp.txt +++ b/Documentation/power/swsusp.txt @@ -140,21 +140,11 @@ should be sent to the mailing list available through the suspend2 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 freezing of tasks and why are we using it? +A: The freezing of tasks is a mechanism by which user space processes and some +kernel threads are controlled during hibernation or system-wide suspend (on some +architectures). See freezing-of-tasks.txt for details. Q: What is the difference between "platform" and "shutdown"? diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c index 4112afe712b..47001d50a08 100644 --- a/arch/i386/kernel/apm.c +++ b/arch/i386/kernel/apm.c @@ -222,6 +222,7 @@ #include <linux/capability.h> #include <linux/device.h> #include <linux/kernel.h> +#include <linux/freezer.h> #include <linux/smp.h> #include <linux/dmi.h> #include <linux/suspend.h> @@ -2311,7 +2312,6 @@ 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 ) { diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c index 7f8b7af2b95..21db8f56c9a 100644 --- a/arch/i386/kernel/io_apic.c +++ b/arch/i386/kernel/io_apic.c @@ -667,6 +667,7 @@ static int balanced_irq(void *unused) set_pending_irq(i, cpumask_of_cpu(0)); } + set_freezable(); for ( ; ; ) { time_remaining = schedule_timeout_interruptible(time_remaining); try_to_freeze(); diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 4503290da40..06eaa11cbc2 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -68,6 +68,7 @@ #include <linux/loop.h> #include <linux/compat.h> #include <linux/suspend.h> +#include <linux/freezer.h> #include <linux/writeback.h> #include <linux/buffer_head.h> /* for invalidate_bdev() */ #include <linux/completion.h> @@ -600,13 +601,6 @@ 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) { diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index 7c294a40002..31be33e4f11 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -1593,6 +1593,7 @@ static int kcdrwd(void *foobar) long min_sleep_time, residue; set_user_nice(current, -20); + set_freezable(); for (;;) { DECLARE_WAITQUEUE(wait, current); diff --git a/drivers/char/apm-emulation.c b/drivers/char/apm-emulation.c index 179c7a3b6e7..ec116df919d 100644 --- a/drivers/char/apm-emulation.c +++ b/drivers/char/apm-emulation.c @@ -20,6 +20,7 @@ #include <linux/sched.h> #include <linux/pm.h> #include <linux/apm-emulation.h> +#include <linux/freezer.h> #include <linux/device.h> #include <linux/kernel.h> #include <linux/list.h> @@ -329,13 +330,8 @@ apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg) /* * 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 +361,8 @@ apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg) /* * 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 +589,6 @@ 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 diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c index b3ab42e0dd4..83c1151ec7a 100644 --- a/drivers/char/hvc_console.c +++ b/drivers/char/hvc_console.c @@ -679,6 +679,7 @@ static int khvcd(void *unused) int poll_mask; struct hvc_struct *hp; + set_freezable(); __set_current_state(TASK_RUNNING); do { poll_mask = 0; diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index 7b622300d0e..804875de580 100644 --- a/drivers/edac/edac_mc.c +++ b/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(); diff --git a/drivers/ieee1394/ieee1394_core.c b/drivers/ieee1394/ieee1394_core.c index 0fc8c6e559e..ee45259573c 100644 --- a/drivers/ieee1394/ieee1394_core.c +++ b/drivers/ieee1394/ieee1394_core.c @@ -30,6 +30,7 @@ #include <linux/moduleparam.h> #include <linux/bitops.h> #include <linux/kdev_t.h> +#include <linux/freezer.h> #include <linux/suspend.h> #include <linux/kthread.h> #include <linux/preempt.h> @@ -1128,8 +1129,6 @@ 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); diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c index 51a12062ed3..2ffd53461db 100644 --- a/drivers/ieee1394/nodemgr.c +++ b/drivers/ieee1394/nodemgr.c @@ -1699,6 +1699,7 @@ static int nodemgr_host_thread(void *__hi) unsigned int g, generation = 0; int i, reset_cycles = 0; + set_freezable(); /* Setup our device-model entries */ nodemgr_create_host_dev_files(host); diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c index bd686a2a517..20896d5e5f0 100644 --- a/drivers/input/gameport/gameport.c +++ b/drivers/input/gameport/gameport.c @@ -445,6 +445,7 @@ static struct gameport *gameport_get_pending_child(struct gameport *parent) static int gameport_thread(void *nothing) { + set_freezable(); do { gameport_handle_event(); wait_event_interruptible(gameport_wait, diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c index a8f3bc1dff2..372ca493119 100644 --- a/drivers/input/serio/serio.c +++ b/drivers/input/serio/serio.c @@ -384,6 +384,7 @@ static struct serio *serio_get_pending_child(struct serio *parent) static int serio_thread(void *nothing) { + set_freezable(); do { serio_handle_event(); wait_event_interruptible(serio_wait, diff --git a/drivers/input/touchscreen/ucb1400_ts.c b/drivers/input/touchscreen/ucb1400_ts.c index f0cbcdb008e..36f94401915 100644 --- a/drivers/input/touchscreen/ucb1400_ts.c +++ b/drivers/input/touchscreen/ucb1400_ts.c @@ -292,6 +292,7 @@ static int ucb1400_ts_thread(void *_ucb) sched_setscheduler(tsk, SCHED_FIFO, ¶m); + set_freezable(); while (!kthread_should_stop()) { unsigned int x, y, p; long timeout; diff --git a/drivers/macintosh/therm_adt746x.c b/drivers/macintosh/therm_adt746x.c index bd55e6ab99f..f25685b9b7c 100644 --- a/drivers/macintosh/therm_adt746x.c +++ b/drivers/macintosh/therm_adt746x.c @@ -335,6 +335,7 @@ static int monitor_task(void *arg) { struct thermostat* th = arg; + set_freezable(); while(!kthread_should_stop()) { try_to_freeze(); msleep_interruptible(2000); diff --git a/drivers/macintosh/windfarm_core.c b/drivers/macintosh/windfarm_core.c index 4fcb245ba18..e18d265d5d3 100644 --- a/drivers/macintosh/windfarm_core.c +++ b/drivers/macintosh/windfarm_core.c @@ -92,6 +92,7 @@ static int wf_thread_func(void *data) DBG("wf: thread started\n"); + set_freezable(); while(!kthread_should_stop()) { if (time_after_eq(jiffies, next)) { wf_notify(WF_EVENT_TICK, NULL); diff --git a/drivers/md/md.c b/drivers/md/md.c index 33beaa7da08..9aefc4a023d 100644 --- a/drivers/md/md.c +++ b/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()) { diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c index f4e4ca2dcad..b6c7f6610ec 100644 --- a/drivers/media/dvb/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb/dvb-core/dvb_frontend.c @@ -523,6 +523,7 @@ static int dvb_frontend_thread(void *data) dvb_frontend_init(fe); + set_freezable(); while (1) { up(&fepriv->sem); /* is locked when we enter the thread... */ restart: diff --git a/drivers/media/video/cx88/cx88-tvaudio.c b/drivers/media/video/cx88/cx88-tvaudio.c index 259ea08e784..1cc2d286a1c 100644 --- a/drivers/media/video/cx88/cx88-tvaudio.c +++ b/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()) diff --git a/drivers/media/video/msp3400-kthreads.c b/drivers/media/video/msp3400-kthreads.c index e1821eb82fb..d5ee2629121 100644 --- a/drivers/media/video/msp3400-kthreads.c +++ b/drivers/media/video/msp3400-kthreads.c @@ -23,6 +23,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/i2c.h> +#include <linux/freezer.h> #include <linux/videodev.h> #include <linux/videodev2.h> #include <media/v4l2-common.h> @@ -468,6 +469,7 @@ 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 +648,7 @@ 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 +942,7 @@ 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); diff --git a/drivers/media/video/tvaudio.c b/drivers/media/video/tvaudio.c index c9bf9dbc2ea..9da338dc4f3 100644 --- a/drivers/media/video/tvaudio.c +++ b/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()) diff --git a/drivers/media/video/video-buf-dvb.c b/drivers/media/video/video-buf-dvb.c index fcc5467e763..e617925ba31 100644 --- a/drivers/media/video/video-buf-dvb.c +++ b/drivers/media/video/video-buf-dvb.c @@ -47,6 +47,7 @@ static int videobuf_dvb_thread(void *data) int err; dprintk("dvb thread started\n"); + set_freezable(); videobuf_read_start(&dvb->dvbq); for (;;) { diff --git a/drivers/media/video/vivi.c b/drivers/media/video/vivi.c index f7e1d191037..3ef4d0159c3 100644 --- a/drivers/media/video/vivi.c +++ b/drivers/media/video/vivi.c @@ -573,6 +573,7 @@ static int vivi_thread(void *data) dprintk(1,"thread started\n"); mod_timer(&dma_q->timeout, jiffies+BUFFER_TIMEOUT); + set_freezable(); for (;;) { vivi_sleep(dma_q); diff --git a/drivers/mfd/ucb1x00-ts.c b/drivers/mfd/ucb1x00-ts.c index 38e815a2e87..fdbaa776f24 100644 --- a/drivers/mfd/ucb1x00-ts.c +++ b/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; diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c index 4fb2089dc69..b53dac8d1b6 100644 --- a/drivers/mmc/card/queue.c +++ b/drivers/mmc/card/queue.c @@ -11,6 +11,7 @@ */ #include <linux/module.h> #include <linux/blkdev.h> +#include <linux/freezer.h> #include <linux/kthread.h> #include <linux/mmc/card.h> @@ -44,11 +45,7 @@ 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 { diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 51bc7e2f1f2..ef89780eb9d 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -16,6 +16,7 @@ #include <linux/mtd/mtd.h> #include <linux/blkdev.h> #include <linux/blkpg.h> +#include <linux/freezer.h> #include <linux/spinlock.h> #include <linux/hdreg.h> #include <linux/init.h> @@ -80,7 +81,7 @@ 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()) { diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 9ecaf77eca9..ab2174a56bc 100644 --- a/drivers/mtd/ubi/wl.c +++ b/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; diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c index 1c54908fdc4..ee1cc14db38 100644 --- a/drivers/net/wireless/airo.c +++ b/drivers/net/wireless/airo.c @@ -3086,7 +3086,8 @@ 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(); diff --git a/drivers/net/wireless/libertas/main.c b/drivers/net/wireless/libertas/main.c index 4a59306a3f0..9f366242c39 100644 --- a/drivers/net/wireless/libertas/main.c +++ b/drivers/net/wireless/libertas/main.c @@ -613,6 +613,7 @@ static int wlan_service_main_thread(void *data) init_waitqueue_entry(&wait, current); + set_freezable(); for (;;) { lbs_deb_thread( "main-thread 111: intcounter=%d " "currenttxskb=%p dnld_sent=%d\n", diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c index 50cad3a59a6..7c93a108f9b 100644 --- a/drivers/pcmcia/cs.c +++ b/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; diff --git a/drivers/pnp/pnpbios/core.c b/drivers/pnp/pnpbios/core.c index 3a201b77b96..03baf1c64a2 100644 --- a/drivers/pnp/pnpbios/core.c +++ b/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; diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c index d70ddfda93f..9c5342e7a69 100644 --- a/drivers/scsi/libsas/sas_scsi_host.c +++ b/drivers/scsi/libsas/sas_scsi_host.c @@ -40,6 +40,7 @@ #include <linux/err.h> #include <linux/blkdev.h> +#include <linux/freezer.h> #include <linux/scatterlist.h> /* ---------- SCSI Host glue ---------- */ @@ -868,8 +869,6 @@ static int sas_queue_thread(void *_sas_ha) { struct sas_ha_struct *sas_ha = _sas_ha; - current->flags |= PF_NOFREEZE; - while (1) { set_current_state(TASK_INTERRUPTIBLE); schedule(); diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 9adb64ac054..8a525abda30 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -19,6 +19,7 @@ #include <linux/timer.h> #include <linux/string.h> #include <linux/kernel.h> +#include <linux/freezer.h> #include <linux/kthread.h> #include <linux/interrupt.h> #include <linux/blkdev.h> @@ -1516,8 +1517,6 @@ 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. diff --git a/drivers/usb/atm/ueagle-atm.c b/drivers/usb/atm/ueagle-atm.c index 4973e147bc7..8f046659b4e 100644 --- a/drivers/usb/atm/ueagle-atm.c +++ b/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) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 50e79010401..fd74c50b180 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2728,6 +2728,7 @@ loop: static int hub_thread(void *__unused) { + set_freezable(); do { hub_events(); wait_event_interruptible(khubd_wait, diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c index 8712ef98717..be7a1bd2823 100644 --- a/drivers/usb/gadget/file_storage.c +++ b/drivers/usb/gadget/file_storage.c @@ -3434,6 +3434,9 @@ static int fsg_main_thread(void *fsg_) allow_signal(SIGKILL); allow_signal(SIGUSR1); + /* 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 * that expects a __user pointer and it will work okay. */ diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c index bef8bcd9bd9..28842d208bb 100644 --- a/drivers/usb/storage/usb.c +++ b/drivers/usb/storage/usb.c @@ -311,8 +311,6 @@ static int usb_stor_control_thread(void * __us) struct Scsi_Host *host = us_to_host(us); int autopm_rc; - current->flags |= PF_NOFREEZE; - for(;;) { US_DEBUGP("*** thread sleeping.\n"); if(down_interruptible(&us->sema)) @@ -920,6 +918,7 @@ static int usb_stor_scan_thread(void * __us) printk(KERN_DEBUG "usb-storage: device found at %d\n", us->pusb_dev->devnum); + set_freezable(); /* Wait for the timeout to expire or for a disconnect */ if (delay_use > 0) { printk(KERN_DEBUG "usb-storage: waiting for device " diff --git a/drivers/video/ps3fb.c b/drivers/video/ps3fb.c index 08b7ffbbbbd..3972aa8cf85 100644 --- a/drivers/video/ps3fb.c +++ b/drivers/video/ps3fb.c @@ -812,6 +812,7 @@ static int ps3fb_ioctl(struct fb_info *info, unsigned int cmd, static int ps3fbd(void *arg) { + set_freezable(); while (!kthread_should_stop()) { try_to_freeze(); set_current_state(TASK_INTERRUPTIBLE); diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index f5c5b760ed7..c6332108f1c 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -805,6 +805,7 @@ 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; diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 8b0cbf4a4ad..bd0f2f2353c 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -849,6 +849,7 @@ static int cifs_oplock_thread(void * dummyarg) __u16 netfid; int rc; + set_freezable(); do { if (try_to_freeze()) continue; diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index f4e92661b22..0a1b8bd1dfc 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -363,6 +363,7 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) GFP_KERNEL); } + set_freezable(); while (!kthread_should_stop()) { if (try_to_freeze()) continue; diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c index 0c82dfcfd24..143c5530caf 100644 --- a/fs/jffs2/background.c +++ b/fs/jffs2/background.c @@ -81,6 +81,7 @@ static int jffs2_garbage_collect_thread(void *_c) set_user_nice(current, 10); + set_freezable(); for (;;) { allow_signal(SIGHUP); diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index 26809325469..9fcdef50aad 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -25,6 +25,7 @@ #include <linux/smp.h> #include <linux/smp_lock.h> #include <linux/mutex.h> +#include <linux/freezer.h> #include <linux/sunrpc/types.h> #include <linux/sunrpc/stats.h> @@ -119,6 +120,7 @@ lockd(struct svc_rqst *rqstp) complete(&lockd_start_done); daemonize("lockd"); + set_freezable(); /* Process request with signals blocked, but allow SIGKILL. */ allow_signal(SIGKILL); diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c index 75f309c8741..a796be5051b 100644 --- a/fs/nfs/callback.c +++ b/fs/nfs/callback.c @@ -14,6 +14,7 @@ #include <linux/sunrpc/svcsock.h> #include <linux/nfs_fs.h> #include <linux/mutex.h> +#include <linux/freezer.h> #include <net/inet_sock.h> @@ -67,6 +68,7 @@ static void nfs_callback_svc(struct svc_rqst *rqstp) daemonize("nfsv4-svc"); /* Process request with signals blocked, but allow SIGKILL. */ allow_signal(SIGKILL); + set_freezable(); complete(&nfs_callback_info.started); diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index ff55950efb4..5c8192bcbce 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -19,6 +19,7 @@ #include <linux/slab.h> #include <linux/smp.h> #include <linux/smp_lock.h> +#include <linux/freezer.h> #include <linux/fs_struct.h> #include <linux/sunrpc/types.h> @@ -432,6 +433,7 @@ nfsd(struct svc_rqst *rqstp) * dirty pages. */ current->flags |= PF_LESS_THROTTLE; + set_freezable(); /* * The main request loop diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c index 06894cf00b1..4528f9a3f30 100644 --- a/fs/xfs/linux-2.6/xfs_super.c +++ b/fs/xfs/linux-2.6/xfs_super.c @@ -562,6 +562,7 @@ 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); diff --git a/include/linux/freezer.h b/include/linux/freezer.h index 4631086f506..2d38b1a7466 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -1,5 +1,8 @@ /* Freezer declarations */ +#ifndef FREEZER_H_INCLUDED +#define FREEZER_H_INCLUDED + #include <linux/sched.h> #ifdef CONFIG_PM @@ -115,6 +118,14 @@ static inline int freezer_should_skip(struct task_struct *p) 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; } @@ -130,4 +141,7 @@ static inline int try_to_freeze(void) { return 0; } 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(void) {} #endif + +#endif /* FREEZER_H_INCLUDED */ diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index b222ce9e1c8..a6b4c0c08e1 100644 --- a/init/do_mounts_initrd.c +++ b/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); diff --git a/kernel/audit.c b/kernel/audit.c index 5ce8851facf..eb0f9165b40 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -392,6 +392,7 @@ static int kauditd_thread(void *dummy) { struct sk_buff *skb; + set_freezable(); while (!kthread_should_stop()) { skb = skb_dequeue(&audit_skb_queue); wake_up(&audit_backlog_wait); diff --git a/kernel/exit.c b/kernel/exit.c index 57626692cd9..e8af8d0c248 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -31,6 +31,7 @@ #include <linux/mempolicy.h> #include <linux/taskstats_kern.h> #include <linux/delayacct.h> +#include <linux/freezer.h> #include <linux/cpuset.h> #include <linux/syscalls.h> #include <linux/signal.h> @@ -387,6 +388,11 @@ 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 transition begins right now. + */ + current->flags |= PF_NOFREEZE; set_special_pids(1, 1); proc_clear_tty(current); diff --git a/kernel/fork.c b/kernel/fork.c index 7c5c5888e00..ba39bdb2a7b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -923,7 +923,7 @@ static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) { 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; diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 55ba82a85a6..ddff3324778 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -40,6 +40,7 @@ #include <linux/moduleparam.h> #include <linux/percpu.h> #include <linux/notifier.h> +#include <linux/freezer.h> #include <linux/cpu.h> #include <linux/random.h> #include <linux/delay.h> @@ -518,7 +519,6 @@ 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 +558,6 @@ 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 +588,6 @@ 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(); diff --git a/kernel/rtmutex-tester.c b/kernel/rtmutex-tester.c index 015fc633c96..e3055ba6915 100644 --- a/kernel/rtmutex-tester.c +++ b/kernel/rtmutex-tester.c @@ -260,6 +260,7 @@ static int test_func(void *data) int ret; current->flags |= PF_MUTEX_TESTER; + set_freezable(); allow_signal(SIGHUP); for(;;) { diff --git a/kernel/sched.c b/kernel/sched.c index 1c8076676eb..cb31fb4a137 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4912,8 +4912,6 @@ 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)) { @@ -5147,7 +5145,6 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 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); diff --git a/kernel/softirq.c b/kernel/softirq.c index 8de26779016..0f546ddea43 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -14,6 +14,7 @@ #include <linux/notifier.h> #include <linux/percpu.h> #include <linux/cpu.h> +#include <linux/freezer.h> #include <linux/kthread.h> #include <linux/rcupdate.h> #include <linux/smp.h> @@ -488,8 +489,6 @@ void __init softirq_init(void) static int ksoftirqd(void * __bind_cpu) { - current->flags |= PF_NOFREEZE; - set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { diff --git a/kernel/softlockup.c b/kernel/softlockup.c index 0131e296ffb..708d4882c0c 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -10,6 +10,7 @@ #include <linux/cpu.h> #include <linux/init.h> #include <linux/delay.h> +#include <linux/freezer.h> #include <linux/kthread.h> #include <linux/notifier.h> #include <linux/module.h> @@ -116,7 +117,6 @@ static int watchdog(void * __bind_cpu) struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; sched_setscheduler(current, SCHED_FIFO, ¶m); - current->flags |= PF_NOFREEZE; /* initialize timestamp */ touch_softlockup_watchdog(); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index d7d3fa3072e..1935302cc64 100644 --- a/kernel/workqueue.c +++ b/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); diff --git a/mm/pdflush.c b/mm/pdflush.c index 8ce0900dc95..8f6ee073c0e 100644 --- a/mm/pdflush.c +++ b/mm/pdflush.c @@ -92,6 +92,7 @@ struct pdflush_work { static int __pdflush(struct pdflush_work *my_work) { current->flags |= PF_FLUSHER | PF_SWAPWRITE; + set_freezable(); my_work->fn = NULL; my_work->who = current; INIT_LIST_HEAD(&my_work->list); diff --git a/mm/vmscan.c b/mm/vmscan.c index 2225b7c9df8..d419e10e3da 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1421,6 +1421,7 @@ static int kswapd(void *p) * trying to free the first piece of memory in the first place). */ tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; + set_freezable(); order = 0; for ( ; ; ) { diff --git a/net/bluetooth/bnep/core.c b/net/bluetooth/bnep/core.c index 1c8f4a0c5f4..1f78c3e336d 100644 --- a/net/bluetooth/bnep/core.c +++ b/net/bluetooth/bnep/core.c @@ -36,6 +36,7 @@ #include <linux/signal.h> #include <linux/init.h> #include <linux/wait.h> +#include <linux/freezer.h> #include <linux/errno.h> #include <linux/net.h> #include <net/sock.h> @@ -474,7 +475,6 @@ 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); diff --git a/net/bluetooth/cmtp/core.c b/net/bluetooth/cmtp/core.c index 66bef1ccee2..ca60a4517fd 100644 --- a/net/bluetooth/cmtp/core.c +++ b/net/bluetooth/cmtp/core.c @@ -29,6 +29,7 @@ #include <linux/slab.h> #include <linux/poll.h> #include <linux/fcntl.h> +#include <linux/freezer.h> #include <linux/skbuff.h> #include <linux/socket.h> #include <linux/ioctl.h> @@ -287,7 +288,6 @@ 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); diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c index 450eb0244bb..64d89ca2884 100644 --- a/net/bluetooth/hidp/core.c +++ b/net/bluetooth/hidp/core.c @@ -28,6 +28,7 @@ #include <linux/sched.h> #include <linux/slab.h> #include <linux/poll.h> +#include <linux/freezer.h> #include <linux/fcntl.h> #include <linux/skbuff.h> #include <linux/socket.h> @@ -547,7 +548,6 @@ 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); diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c index 52e04df323e..bb7220770f2 100644 --- a/net/bluetooth/rfcomm/core.c +++ b/net/bluetooth/rfcomm/core.c @@ -33,6 +33,7 @@ #include <linux/sched.h> #include <linux/signal.h> #include <linux/init.h> +#include <linux/freezer.h> #include <linux/wait.h> #include <linux/device.h> #include <linux/net.h> @@ -1940,7 +1941,6 @@ static int rfcomm_run(void *unused) daemonize("krfcommd"); set_user_nice(current, -10); - current->flags |= PF_NOFREEZE; BT_DBG(""); diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 75215331b04..bca787fdbc5 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -3465,6 +3465,8 @@ static int pktgen_thread_worker(void *arg) set_current_state(TASK_INTERRUPTIBLE); + set_freezable(); + while (!kthread_should_stop()) { pkt_dev = next_to_run(t); |