diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index a0f642b6a4b92b556e08c8c1d1e357979cd48322..6110197757a3f6283bf999519f1e7649fb96a867 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -70,6 +70,7 @@ config AUTO_IRQ_AFFINITY
default y
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
menu "System setup"
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4853f9df37bd22a037f122bd7d78a9a6600cc474..df39d20f7425ad9c41679a566ae212f924a222ff 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -192,6 +192,8 @@ config VECTORS_BASE
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "System Type"
choice
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index 7c239a916275b6b66b326e7fc93c6207bdbaf270..33a5b2969eb4addf24e36a59159d72488530dc0b 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -72,6 +72,8 @@ config GENERIC_BUG
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "System Type and features"
source "kernel/time/Kconfig"
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index 8102c79aaa94044369612ab3a8dc3bb6e33aa807..29e71ed6b8a7fb9c5e4b8381244a4c3d5b1d47db 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -64,8 +64,11 @@ config HARDWARE_PM
depends on OPROFILE
source "init/Kconfig"
+
source "kernel/Kconfig.preempt"
+source "kernel/Kconfig.freezer"
+
menu "Blackfin Processor Options"
comment "Processor and Board Settings"
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 9389d38f222f2f749497b106872278a7da5bdd0b..07335e719bf835d7ad5e88a6b844f07210b4b6ba 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -62,6 +62,8 @@ config HZ
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "General setup"
source "fs/Kconfig.binfmt"
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index a5aac1b075628b8a30004d52bb73d2e1ce7d978f..9d1552a9ee2c88ddb40bc7d70dea316f725d2843 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -66,6 +66,8 @@ mainmenu "Fujitsu FR-V Kernel Configuration"
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Fujitsu FR-V system setup"
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index c7966746fbfec582938b77a37baaed384d1b0ec2..bd1995403c67d0f9b37b34674a6c80ab7ee2a76b 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -90,6 +90,8 @@ config HZ
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
source "arch/h8300/Kconfig.cpu"
menu "Executable file formats"
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 3b7aa38254a8408b5564a260eb7a2ef30cf8d5f8..912c57db2d2180888ee9b366d7fae435c45c354d 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -7,6 +7,8 @@ mainmenu "IA-64 Linux Kernel Configuration"
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Processor type and features"
config IA64
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index 00289c178f895a6ad62a7fb34603af08d52bc961..dbaed4a638153bc43c5fa4d6e138039bb5cca8df 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -42,6 +42,8 @@ config HZ
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Processor type and features"
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 677c93a490f6f49501e4c7d2e375fd42bb4dabc5..836fb66f080dcbadeb5f6d96fba8f01679d85d02 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -62,6 +62,8 @@ mainmenu "Linux/68k Kernel Configuration"
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Platform dependent setup"
config EISA
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index 0a8998315e5ed9fcdada66d87c5ee1127e35b9ac..76b66feb74df82d42b21a4b8ac67d6df0f498812 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -75,6 +75,8 @@ config NO_IOPORT
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Processor type and features"
choice
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index b905744d79153be3d3170e9f81ce4e0805974d71..5f149b030c0f9fc7949793c6d8591d4bf0fd0450 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1885,6 +1885,8 @@ config PROBE_INITRD_HEADER
add initrd or initramfs image to the kernel image.
Otherwise, say N.
+source "kernel/Kconfig.freezer"
+
menu "Bus options (PCI, PCMCIA, EISA, ISA, TC)"
config HW_HAS_EISA
diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index dd557c9cf001be6226441b78cb84753f5e50cb15..9a9f433588792f5030796b2686193f4983c98ce9 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -68,6 +68,8 @@ mainmenu "Matsushita MN10300/AM33 Kernel Configuration"
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Matsushita MN10300 system setup"
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 8313fccced5e1553f6f3d7ff484d897d2d20b812..2bd1f6ef5db0c6bd45269701b36b4713c0a6def3 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -90,6 +90,8 @@ config ARCH_MAY_HAVE_PC_FDC
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Processor type and features"
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 380baa1780e9197b060ce1594aa098340d4da538..9391199d9e7731d166b45130fa322e27936b1da0 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -230,6 +230,8 @@ config PPC_OF_PLATFORM_PCI
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
source "arch/powerpc/sysdev/Kconfig"
source "arch/powerpc/platforms/Kconfig"
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index bc581d8a7cd9c35995e6bb75ae1f17d101840de1..70b7645ce745aa03863360201183a832aec3f130 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -78,6 +78,8 @@ config S390
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Base setup"
comment "Processor type and features"
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 5131d50f851ac44f0a81709708023e2c6f00a5af..2ed5713b7540ab4985e3b1fda64b9365d5a1a2fe 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -106,6 +106,8 @@ config IO_TRAPPED
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "System type"
#
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 97671dac12a649765e3b8fda6d22317963872749..e594559c8dbaa7658f56f079354e8ed25468fdcf 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -37,6 +37,8 @@ config HZ
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "General machine setup"
config SMP
diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index 5446e2a499b13d36e3e50a529e85cd0e91ad5de4..035b15af90d8a668583001ef9610ab761d7b9478 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -96,6 +96,7 @@ config GENERIC_HARDIRQS_NO__DO_IRQ
def_bool y
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
menu "Processor type and features"
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 6976812cfb184553bb93778bba38b2f3c01f922c..393bccfe1785108579dc6c18bab682f2e7984110 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -229,6 +229,8 @@ endmenu
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
+
source "drivers/block/Kconfig"
source "arch/um/Kconfig.char"
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bd3c2c53873ecb4cd0b944e31996b746884d6cf0..49349ba77d80b81141deb6065510e54fc74eb077 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -193,6 +193,7 @@ config X86_TRAMPOLINE
config KTIME_SCALAR
def_bool X86_32
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
menu "Processor type and features"
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 02e417d3d8e95815713b1420146b069112da6b99..a213260b51e5b4d8d3d64d7aebc85d2b2f21eb74 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -55,6 +55,7 @@ config HZ
default 100
source "init/Kconfig"
+source "kernel/Kconfig.freezer"
menu "Processor type and features"
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index e2877454ec82df3205c0251f9c9759db9334dedb..9c22396e8b50355e3058e93807f293112622079f 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -48,3 +48,9 @@ SUBSYS(devices)
#endif
/* */
+
+#ifdef CONFIG_CGROUP_FREEZER
+SUBSYS(freezer)
+#endif
+
+/* */
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index 17e3bb42dd3cc541373aba08191e3592bdc6f67d..8f225339eee9e49329b842803d89c2b4c90f9d38 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -46,26 +46,11 @@ static inline bool should_send_signal(struct task_struct *p)
/*
* Wake up a frozen process
- *
- * task_lock() is taken to prevent the race with refrigerator() which may
- * occur if the freezing of tasks fails. Namely, without the lock, if the
- * freezing of tasks failed, thaw_tasks() might have run before a task in
- * refrigerator() could call frozen_process(), in which case the task would be
- * frozen and no one would thaw it.
*/
-static inline int thaw_process(struct task_struct *p)
-{
- task_lock(p);
- if (frozen(p)) {
- p->flags &= ~PF_FROZEN;
- task_unlock(p);
- wake_up_process(p);
- return 1;
- }
- clear_freeze_flag(p);
- task_unlock(p);
- return 0;
-}
+extern int __thaw_process(struct task_struct *p);
+
+/* Takes and releases task alloc lock using task_lock() */
+extern int thaw_process(struct task_struct *p);
extern void refrigerator(void);
extern int freeze_processes(void);
@@ -83,6 +68,12 @@ static inline int try_to_freeze(void)
extern bool freeze_task(struct task_struct *p, bool sig_only);
extern void cancel_freezing(struct task_struct *p);
+#ifdef CONFIG_CGROUP_FREEZER
+extern int cgroup_frozen(struct task_struct *task);
+#else /* !CONFIG_CGROUP_FREEZER */
+static inline int cgroup_frozen(struct task_struct *task) { return 0; }
+#endif /* !CONFIG_CGROUP_FREEZER */
+
/*
* The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
* calls wait_for_completion(&vfork) and reset right after it returns from this
diff --git a/init/Kconfig b/init/Kconfig
index 5ceff3249a2d84cd23110b99fb3f8a076e8cf56c..8828ed0b2051f16df1d3a491419d3e868ac8d014 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -299,6 +299,13 @@ config CGROUP_NS
for instance virtual servers and checkpoint/restart
jobs.
+config CGROUP_FREEZER
+ bool "control group freezer subsystem"
+ depends on CGROUPS
+ help
+ Provides a way to freeze and unfreeze all tasks in a
+ cgroup.
+
config CGROUP_DEVICE
bool "Device controller for cgroups"
depends on CGROUPS && EXPERIMENTAL
diff --git a/kernel/Kconfig.freezer b/kernel/Kconfig.freezer
new file mode 100644
index 0000000000000000000000000000000000000000..a3bb4cb52539b0d8d0e420a4615fa700c15d654f
--- /dev/null
+++ b/kernel/Kconfig.freezer
@@ -0,0 +1,2 @@
+config FREEZER
+ def_bool PM_SLEEP || CGROUP_FREEZER
diff --git a/kernel/Makefile b/kernel/Makefile
index e8194d15d5f4cc1f3c7f4fb398cd4a93d3eccd9d..066550aa61c5018a32dff60fcd75e6ffdebbdedd 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CGROUPS) += cgroup.o
obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o
+obj-$(CONFIG_CGROUP_FREEZER) += cgroup_freezer.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o
obj-$(CONFIG_UTS_NS) += utsname.o
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
new file mode 100644
index 0000000000000000000000000000000000000000..b08722de610c38aa41ef0fcbb125e8c63eb48749
--- /dev/null
+++ b/kernel/cgroup_freezer.c
@@ -0,0 +1,366 @@
+/*
+ * cgroup_freezer.c - control group freezer subsystem
+ *
+ * Copyright IBM Corporation, 2007
+ *
+ * Author : Cedric Le Goater <clg@fr.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include <linux/module.h>
+#include <linux/cgroup.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/freezer.h>
+#include <linux/seq_file.h>
+
+enum freezer_state {
+ STATE_RUNNING = 0,
+ STATE_FREEZING,
+ STATE_FROZEN,
+};
+
+struct freezer {
+ struct cgroup_subsys_state css;
+ enum freezer_state state;
+ spinlock_t lock; /* protects _writes_ to state */
+};
+
+static inline struct freezer *cgroup_freezer(
+ struct cgroup *cgroup)
+{
+ return container_of(
+ cgroup_subsys_state(cgroup, freezer_subsys_id),
+ struct freezer, css);
+}
+
+static inline struct freezer *task_freezer(struct task_struct *task)
+{
+ return container_of(task_subsys_state(task, freezer_subsys_id),
+ struct freezer, css);
+}
+
+int cgroup_frozen(struct task_struct *task)
+{
+ struct freezer *freezer;
+ enum freezer_state state;
+
+ task_lock(task);
+ freezer = task_freezer(task);
+ state = freezer->state;
+ task_unlock(task);
+
+ return state == STATE_FROZEN;
+}
+
+/*
+ * cgroups_write_string() limits the size of freezer state strings to
+ * CGROUP_LOCAL_BUFFER_SIZE
+ */
+static const char *freezer_state_strs[] = {
+ "RUNNING",
+ "FREEZING",
+ "FROZEN",
+};
+
+/*
+ * State diagram
+ * Transitions are caused by userspace writes to the freezer.state file.
+ * The values in parenthesis are state labels. The rest are edge labels.
+ *
+ * (RUNNING) --FROZEN--> (FREEZING) --FROZEN--> (FROZEN)
+ * ^ ^ | |
+ * | \_______RUNNING_______/ |
+ * \_____________________________RUNNING___________/
+ */
+
+struct cgroup_subsys freezer_subsys;
+
+/* Locks taken and their ordering
+ * ------------------------------
+ * css_set_lock
+ * cgroup_mutex (AKA cgroup_lock)
+ * task->alloc_lock (AKA task_lock)
+ * freezer->lock
+ * task->sighand->siglock
+ *
+ * cgroup code forces css_set_lock to be taken before task->alloc_lock
+ *
+ * freezer_create(), freezer_destroy():
+ * cgroup_mutex [ by cgroup core ]
+ *
+ * can_attach():
+ * cgroup_mutex
+ *
+ * cgroup_frozen():
+ * task->alloc_lock (to get task's cgroup)
+ *
+ * freezer_fork() (preserving fork() performance means can't take cgroup_mutex):
+ * task->alloc_lock (to get task's cgroup)
+ * freezer->lock
+ * sighand->siglock (if the cgroup is freezing)
+ *
+ * freezer_read():
+ * cgroup_mutex
+ * freezer->lock
+ * read_lock css_set_lock (cgroup iterator start)
+ *
+ * freezer_write() (freeze):
+ * cgroup_mutex
+ * freezer->lock
+ * read_lock css_set_lock (cgroup iterator start)
+ * sighand->siglock
+ *
+ * freezer_write() (unfreeze):
+ * cgroup_mutex
+ * freezer->lock
+ * read_lock css_set_lock (cgroup iterator start)
+ * task->alloc_lock (to prevent races with freeze_task())
+ * sighand->siglock
+ */
+static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
+ struct cgroup *cgroup)
+{
+ struct freezer *freezer;
+
+ freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL);
+ if (!freezer)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock_init(&freezer->lock);
+ freezer->state = STATE_RUNNING;
+ return &freezer->css;
+}
+
+static void freezer_destroy(struct cgroup_subsys *ss,
+ struct cgroup *cgroup)
+{
+ kfree(cgroup_freezer(cgroup));
+}
+
+
+static int freezer_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *new_cgroup,
+ struct task_struct *task)
+{
+ struct freezer *freezer;
+ int retval = 0;
+
+ /*
+ * The call to cgroup_lock() in the freezer.state write method prevents
+ * a write to that file racing against an attach, and hence the
+ * can_attach() result will remain valid until the attach completes.
+ */
+ freezer = cgroup_freezer(new_cgroup);
+ if (freezer->state == STATE_FROZEN)
+ retval = -EBUSY;
+ return retval;
+}
+
+static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
+{
+ struct freezer *freezer;
+
+ task_lock(task);
+ freezer = task_freezer(task);
+ task_unlock(task);
+
+ BUG_ON(freezer->state == STATE_FROZEN);
+ spin_lock_irq(&freezer->lock);
+ /* Locking avoids race with FREEZING -> RUNNING transitions. */
+ if (freezer->state == STATE_FREEZING)
+ freeze_task(task, true);
+ spin_unlock_irq(&freezer->lock);
+}
+
+/*
+ * caller must hold freezer->lock
+ */
+static void check_if_frozen(struct cgroup *cgroup,
+ struct freezer *freezer)
+{
+ struct cgroup_iter it;
+ struct task_struct *task;
+ unsigned int nfrozen = 0, ntotal = 0;
+
+ cgroup_iter_start(cgroup, &it);
+ while ((task = cgroup_iter_next(cgroup, &it))) {
+ ntotal++;
+ /*
+ * Task is frozen or will freeze immediately when next it gets
+ * woken
+ */
+ if (frozen(task) ||
+ (task_is_stopped_or_traced(task) && freezing(task)))
+ nfrozen++;
+ }
+
+ /*
+ * Transition to FROZEN when no new tasks can be added ensures
+ * that we never exist in the FROZEN state while there are unfrozen
+ * tasks.
+ */
+ if (nfrozen == ntotal)
+ freezer->state = STATE_FROZEN;
+ cgroup_iter_end(cgroup, &it);
+}
+
+static int freezer_read(struct cgroup *cgroup, struct cftype *cft,
+ struct seq_file *m)
+{
+ struct freezer *freezer;
+ enum freezer_state state;
+
+ if (!cgroup_lock_live_group(cgroup))
+ return -ENODEV;
+
+ freezer = cgroup_freezer(cgroup);
+ spin_lock_irq(&freezer->lock);
+ state = freezer->state;
+ if (state == STATE_FREEZING) {
+ /* We change from FREEZING to FROZEN lazily if the cgroup was
+ * only partially frozen when we exitted write. */
+ check_if_frozen(cgroup, freezer);
+ state = freezer->state;
+ }
+ spin_unlock_irq(&freezer->lock);
+ cgroup_unlock();
+
+ seq_puts(m, freezer_state_strs[state]);
+ seq_putc(m, '\n');
+ return 0;
+}
+
+static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
+{
+ struct cgroup_iter it;
+ struct task_struct *task;
+ unsigned int num_cant_freeze_now = 0;
+
+ freezer->state = STATE_FREEZING;
+ cgroup_iter_start(cgroup, &it);
+ while ((task = cgroup_iter_next(cgroup, &it))) {
+ if (!freeze_task(task, true))
+ continue;
+ if (task_is_stopped_or_traced(task) && freezing(task))
+ /*
+ * The freeze flag is set so these tasks will
+ * immediately go into the fridge upon waking.
+ */
+ continue;
+ if (!freezing(task) && !freezer_should_skip(task))
+ num_cant_freeze_now++;
+ }
+ cgroup_iter_end(cgroup, &it);
+
+ return num_cant_freeze_now ? -EBUSY : 0;
+}
+
+static int unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
+{
+ struct cgroup_iter it;
+ struct task_struct *task;
+
+ cgroup_iter_start(cgroup, &it);
+ while ((task = cgroup_iter_next(cgroup, &it))) {
+ int do_wake;
+
+ task_lock(task);
+ do_wake = __thaw_process(task);
+ task_unlock(task);
+ if (do_wake)
+ wake_up_process(task);
+ }
+ cgroup_iter_end(cgroup, &it);
+ freezer->state = STATE_RUNNING;
+
+ return 0;
+}
+
+static int freezer_change_state(struct cgroup *cgroup,
+ enum freezer_state goal_state)
+{
+ struct freezer *freezer;
+ int retval = 0;
+
+ freezer = cgroup_freezer(cgroup);
+ spin_lock_irq(&freezer->lock);
+ check_if_frozen(cgroup, freezer); /* may update freezer->state */
+ if (goal_state == freezer->state)
+ goto out;
+ switch (freezer->state) {
+ case STATE_RUNNING:
+ retval = try_to_freeze_cgroup(cgroup, freezer);
+ break;
+ case STATE_FREEZING:
+ if (goal_state == STATE_FROZEN) {
+ /* Userspace is retrying after
+ * "/bin/echo FROZEN > freezer.state" returned -EBUSY */
+ retval = try_to_freeze_cgroup(cgroup, freezer);
+ break;
+ }
+ /* state == FREEZING and goal_state == RUNNING, so unfreeze */
+ case STATE_FROZEN:
+ retval = unfreeze_cgroup(cgroup, freezer);
+ break;
+ default:
+ break;
+ }
+out:
+ spin_unlock_irq(&freezer->lock);
+
+ return retval;
+}
+
+static int freezer_write(struct cgroup *cgroup,
+ struct cftype *cft,
+ const char *buffer)
+{
+ int retval;
+ enum freezer_state goal_state;
+
+ if (strcmp(buffer, freezer_state_strs[STATE_RUNNING]) == 0)
+ goal_state = STATE_RUNNING;
+ else if (strcmp(buffer, freezer_state_strs[STATE_FROZEN]) == 0)
+ goal_state = STATE_FROZEN;
+ else
+ return -EIO;
+
+ if (!cgroup_lock_live_group(cgroup))
+ return -ENODEV;
+ retval = freezer_change_state(cgroup, goal_state);
+ cgroup_unlock();
+ return retval;
+}
+
+static struct cftype files[] = {
+ {
+ .name = "state",
+ .read_seq_string = freezer_read,
+ .write_string = freezer_write,
+ },
+};
+
+static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
+{
+ return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files));
+}
+
+struct cgroup_subsys freezer_subsys = {
+ .name = "freezer",
+ .create = freezer_create,
+ .destroy = freezer_destroy,
+ .populate = freezer_populate,
+ .subsys_id = freezer_subsys_id,
+ .can_attach = freezer_can_attach,
+ .attach = NULL,
+ .fork = freezer_fork,
+ .exit = NULL,
+};
diff --git a/kernel/freezer.c b/kernel/freezer.c
index cb0931f893061bb5d2b04678ac925dcc498a2f15..ba6248b323ef7f64fb78aa1123c2940ffce3e64d 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -120,3 +120,35 @@ void cancel_freezing(struct task_struct *p)
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
+
+/*
+ * Wake up a frozen process
+ *
+ * task_lock() is needed to prevent the race with refrigerator() which may
+ * occur if the freezing of tasks fails. Namely, without the lock, if the
+ * freezing of tasks failed, thaw_tasks() might have run before a task in
+ * refrigerator() could call frozen_process(), in which case the task would be
+ * frozen and no one would thaw it.
+ */
+int __thaw_process(struct task_struct *p)
+{
+ if (frozen(p)) {
+ p->flags &= ~PF_FROZEN;
+ return 1;
+ }
+ clear_freeze_flag(p);
+ return 0;
+}
+
+int thaw_process(struct task_struct *p)
+{
+ task_lock(p);
+ if (__thaw_process(p) == 1) {
+ task_unlock(p);
+ wake_up_process(p);
+ return 1;
+ }
+ task_unlock(p);
+ return 0;
+}
+EXPORT_SYMBOL(thaw_process);
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index ebdd7f55273dc1fe77fd068650484651d7a5dddb..dcd165f92a887881eefaf9f67bf6c612a4a94547 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -85,9 +85,6 @@ config PM_SLEEP
depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
default y
-config FREEZER
- def_bool PM_SLEEP
-
config SUSPEND
bool "Suspend to RAM and standby"
depends on PM && ARCH_SUSPEND_POSSIBLE