Merge branch 'akpm' (fixes from Andrew)
Merge patches from Andrew Morton:
"13 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm: memcg: do not allow task about to OOM kill to bypass the limit
mm: memcg: fix race condition between memcg teardown and swapin
thp: move preallocated PTE page table on move_huge_pmd()
mfd/rtc: s5m: fix register updating by adding regmap for RTC
rtc: s5m: enable IRQ wake during suspend
rtc: s5m: limit endless loop waiting for register update
rtc: s5m: fix unsuccesful IRQ request during probe
drivers/rtc/rtc-s5m.c: fix info->rtc assignment
include/linux/kernel.h: make might_fault() a nop for !MMU
drivers/rtc/rtc-at91rm9200.c: correct alarm over day/month wrap
procfs: also fix proc_reg_get_unmapped_area() for !MMU case
mm: memcg: do not declare OOM from __GFP_NOFAIL allocations
include/linux/hugetlb.h: make isolate_huge_page() an inline
diff --git a/drivers/mfd/sec-core.c b/drivers/mfd/sec-core.c
index 34c18fb..54cc255 100644
--- a/drivers/mfd/sec-core.c
+++ b/drivers/mfd/sec-core.c
@@ -81,31 +81,31 @@
int sec_reg_read(struct sec_pmic_dev *sec_pmic, u8 reg, void *dest)
{
- return regmap_read(sec_pmic->regmap, reg, dest);
+ return regmap_read(sec_pmic->regmap_pmic, reg, dest);
}
EXPORT_SYMBOL_GPL(sec_reg_read);
int sec_bulk_read(struct sec_pmic_dev *sec_pmic, u8 reg, int count, u8 *buf)
{
- return regmap_bulk_read(sec_pmic->regmap, reg, buf, count);
+ return regmap_bulk_read(sec_pmic->regmap_pmic, reg, buf, count);
}
EXPORT_SYMBOL_GPL(sec_bulk_read);
int sec_reg_write(struct sec_pmic_dev *sec_pmic, u8 reg, u8 value)
{
- return regmap_write(sec_pmic->regmap, reg, value);
+ return regmap_write(sec_pmic->regmap_pmic, reg, value);
}
EXPORT_SYMBOL_GPL(sec_reg_write);
int sec_bulk_write(struct sec_pmic_dev *sec_pmic, u8 reg, int count, u8 *buf)
{
- return regmap_raw_write(sec_pmic->regmap, reg, buf, count);
+ return regmap_raw_write(sec_pmic->regmap_pmic, reg, buf, count);
}
EXPORT_SYMBOL_GPL(sec_bulk_write);
int sec_reg_update(struct sec_pmic_dev *sec_pmic, u8 reg, u8 val, u8 mask)
{
- return regmap_update_bits(sec_pmic->regmap, reg, mask, val);
+ return regmap_update_bits(sec_pmic->regmap_pmic, reg, mask, val);
}
EXPORT_SYMBOL_GPL(sec_reg_update);
@@ -166,6 +166,11 @@
.cache_type = REGCACHE_FLAT,
};
+static const struct regmap_config sec_rtc_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
#ifdef CONFIG_OF
/*
* Only the common platform data elements for s5m8767 are parsed here from the
@@ -266,9 +271,9 @@
break;
}
- sec_pmic->regmap = devm_regmap_init_i2c(i2c, regmap);
- if (IS_ERR(sec_pmic->regmap)) {
- ret = PTR_ERR(sec_pmic->regmap);
+ sec_pmic->regmap_pmic = devm_regmap_init_i2c(i2c, regmap);
+ if (IS_ERR(sec_pmic->regmap_pmic)) {
+ ret = PTR_ERR(sec_pmic->regmap_pmic);
dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
ret);
return ret;
@@ -277,6 +282,15 @@
sec_pmic->rtc = i2c_new_dummy(i2c->adapter, RTC_I2C_ADDR);
i2c_set_clientdata(sec_pmic->rtc, sec_pmic);
+ sec_pmic->regmap_rtc = devm_regmap_init_i2c(sec_pmic->rtc,
+ &sec_rtc_regmap_config);
+ if (IS_ERR(sec_pmic->regmap_rtc)) {
+ ret = PTR_ERR(sec_pmic->regmap_rtc);
+ dev_err(&i2c->dev, "Failed to allocate RTC register map: %d\n",
+ ret);
+ return ret;
+ }
+
if (pdata && pdata->cfg_pmic_irq)
pdata->cfg_pmic_irq();
diff --git a/drivers/mfd/sec-irq.c b/drivers/mfd/sec-irq.c
index 0dd84e9..b441b1b 100644
--- a/drivers/mfd/sec-irq.c
+++ b/drivers/mfd/sec-irq.c
@@ -280,19 +280,19 @@
switch (type) {
case S5M8763X:
- ret = regmap_add_irq_chip(sec_pmic->regmap, sec_pmic->irq,
+ ret = regmap_add_irq_chip(sec_pmic->regmap_pmic, sec_pmic->irq,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
sec_pmic->irq_base, &s5m8763_irq_chip,
&sec_pmic->irq_data);
break;
case S5M8767X:
- ret = regmap_add_irq_chip(sec_pmic->regmap, sec_pmic->irq,
+ ret = regmap_add_irq_chip(sec_pmic->regmap_pmic, sec_pmic->irq,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
sec_pmic->irq_base, &s5m8767_irq_chip,
&sec_pmic->irq_data);
break;
case S2MPS11X:
- ret = regmap_add_irq_chip(sec_pmic->regmap, sec_pmic->irq,
+ ret = regmap_add_irq_chip(sec_pmic->regmap_pmic, sec_pmic->irq,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
sec_pmic->irq_base, &s2mps11_irq_chip,
&sec_pmic->irq_data);
diff --git a/drivers/regulator/s5m8767.c b/drivers/regulator/s5m8767.c
index cbf91e2..aeb40aa 100644
--- a/drivers/regulator/s5m8767.c
+++ b/drivers/regulator/s5m8767.c
@@ -925,7 +925,7 @@
config.dev = s5m8767->dev;
config.init_data = pdata->regulators[i].initdata;
config.driver_data = s5m8767;
- config.regmap = iodev->regmap;
+ config.regmap = iodev->regmap_pmic;
config.of_node = pdata->regulators[i].reg_node;
rdev[i] = devm_regulator_register(&pdev->dev, ®ulators[id],
diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index c0da95e..3281c90 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -220,6 +220,8 @@
at91_alarm_year = tm.tm_year;
+ tm.tm_mon = alrm->time.tm_mon;
+ tm.tm_mday = alrm->time.tm_mday;
tm.tm_hour = alrm->time.tm_hour;
tm.tm_min = alrm->time.tm_min;
tm.tm_sec = alrm->time.tm_sec;
diff --git a/drivers/rtc/rtc-s5m.c b/drivers/rtc/rtc-s5m.c
index b7fd02b..ae8119d 100644
--- a/drivers/rtc/rtc-s5m.c
+++ b/drivers/rtc/rtc-s5m.c
@@ -28,10 +28,20 @@
#include <linux/mfd/samsung/irq.h>
#include <linux/mfd/samsung/rtc.h>
+/*
+ * Maximum number of retries for checking changes in UDR field
+ * of SEC_RTC_UDR_CON register (to limit possible endless loop).
+ *
+ * After writing to RTC registers (setting time or alarm) read the UDR field
+ * in SEC_RTC_UDR_CON register. UDR is auto-cleared when data have
+ * been transferred.
+ */
+#define UDR_READ_RETRY_CNT 5
+
struct s5m_rtc_info {
struct device *dev;
struct sec_pmic_dev *s5m87xx;
- struct regmap *rtc;
+ struct regmap *regmap;
struct rtc_device *rtc_dev;
int irq;
int device_type;
@@ -84,12 +94,31 @@
}
}
+/*
+ * Read RTC_UDR_CON register and wait till UDR field is cleared.
+ * This indicates that time/alarm update ended.
+ */
+static inline int s5m8767_wait_for_udr_update(struct s5m_rtc_info *info)
+{
+ int ret, retry = UDR_READ_RETRY_CNT;
+ unsigned int data;
+
+ do {
+ ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
+ } while (--retry && (data & RTC_UDR_MASK) && !ret);
+
+ if (!retry)
+ dev_err(info->dev, "waiting for UDR update, reached max number of retries\n");
+
+ return ret;
+}
+
static inline int s5m8767_rtc_set_time_reg(struct s5m_rtc_info *info)
{
int ret;
unsigned int data;
- ret = regmap_read(info->rtc, SEC_RTC_UDR_CON, &data);
+ ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
if (ret < 0) {
dev_err(info->dev, "failed to read update reg(%d)\n", ret);
return ret;
@@ -98,15 +127,13 @@
data |= RTC_TIME_EN_MASK;
data |= RTC_UDR_MASK;
- ret = regmap_write(info->rtc, SEC_RTC_UDR_CON, data);
+ ret = regmap_write(info->regmap, SEC_RTC_UDR_CON, data);
if (ret < 0) {
dev_err(info->dev, "failed to write update reg(%d)\n", ret);
return ret;
}
- do {
- ret = regmap_read(info->rtc, SEC_RTC_UDR_CON, &data);
- } while ((data & RTC_UDR_MASK) && !ret);
+ ret = s5m8767_wait_for_udr_update(info);
return ret;
}
@@ -116,7 +143,7 @@
int ret;
unsigned int data;
- ret = regmap_read(info->rtc, SEC_RTC_UDR_CON, &data);
+ ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
if (ret < 0) {
dev_err(info->dev, "%s: fail to read update reg(%d)\n",
__func__, ret);
@@ -126,16 +153,14 @@
data &= ~RTC_TIME_EN_MASK;
data |= RTC_UDR_MASK;
- ret = regmap_write(info->rtc, SEC_RTC_UDR_CON, data);
+ ret = regmap_write(info->regmap, SEC_RTC_UDR_CON, data);
if (ret < 0) {
dev_err(info->dev, "%s: fail to write update reg(%d)\n",
__func__, ret);
return ret;
}
- do {
- ret = regmap_read(info->rtc, SEC_RTC_UDR_CON, &data);
- } while ((data & RTC_UDR_MASK) && !ret);
+ ret = s5m8767_wait_for_udr_update(info);
return ret;
}
@@ -178,7 +203,7 @@
u8 data[8];
int ret;
- ret = regmap_bulk_read(info->rtc, SEC_RTC_SEC, data, 8);
+ ret = regmap_bulk_read(info->regmap, SEC_RTC_SEC, data, 8);
if (ret < 0)
return ret;
@@ -226,7 +251,7 @@
1900 + tm->tm_year, 1 + tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec, tm->tm_wday);
- ret = regmap_raw_write(info->rtc, SEC_RTC_SEC, data, 8);
+ ret = regmap_raw_write(info->regmap, SEC_RTC_SEC, data, 8);
if (ret < 0)
return ret;
@@ -242,20 +267,20 @@
unsigned int val;
int ret, i;
- ret = regmap_bulk_read(info->rtc, SEC_ALARM0_SEC, data, 8);
+ ret = regmap_bulk_read(info->regmap, SEC_ALARM0_SEC, data, 8);
if (ret < 0)
return ret;
switch (info->device_type) {
case S5M8763X:
s5m8763_data_to_tm(data, &alrm->time);
- ret = regmap_read(info->rtc, SEC_ALARM0_CONF, &val);
+ ret = regmap_read(info->regmap, SEC_ALARM0_CONF, &val);
if (ret < 0)
return ret;
alrm->enabled = !!val;
- ret = regmap_read(info->rtc, SEC_RTC_STATUS, &val);
+ ret = regmap_read(info->regmap, SEC_RTC_STATUS, &val);
if (ret < 0)
return ret;
@@ -278,7 +303,7 @@
}
alrm->pending = 0;
- ret = regmap_read(info->rtc, SEC_RTC_STATUS, &val);
+ ret = regmap_read(info->regmap, SEC_RTC_STATUS, &val);
if (ret < 0)
return ret;
break;
@@ -301,7 +326,7 @@
int ret, i;
struct rtc_time tm;
- ret = regmap_bulk_read(info->rtc, SEC_ALARM0_SEC, data, 8);
+ ret = regmap_bulk_read(info->regmap, SEC_ALARM0_SEC, data, 8);
if (ret < 0)
return ret;
@@ -312,14 +337,14 @@
switch (info->device_type) {
case S5M8763X:
- ret = regmap_write(info->rtc, SEC_ALARM0_CONF, 0);
+ ret = regmap_write(info->regmap, SEC_ALARM0_CONF, 0);
break;
case S5M8767X:
for (i = 0; i < 7; i++)
data[i] &= ~ALARM_ENABLE_MASK;
- ret = regmap_raw_write(info->rtc, SEC_ALARM0_SEC, data, 8);
+ ret = regmap_raw_write(info->regmap, SEC_ALARM0_SEC, data, 8);
if (ret < 0)
return ret;
@@ -341,7 +366,7 @@
u8 alarm0_conf;
struct rtc_time tm;
- ret = regmap_bulk_read(info->rtc, SEC_ALARM0_SEC, data, 8);
+ ret = regmap_bulk_read(info->regmap, SEC_ALARM0_SEC, data, 8);
if (ret < 0)
return ret;
@@ -353,7 +378,7 @@
switch (info->device_type) {
case S5M8763X:
alarm0_conf = 0x77;
- ret = regmap_write(info->rtc, SEC_ALARM0_CONF, alarm0_conf);
+ ret = regmap_write(info->regmap, SEC_ALARM0_CONF, alarm0_conf);
break;
case S5M8767X:
@@ -368,7 +393,7 @@
if (data[RTC_YEAR1] & 0x7f)
data[RTC_YEAR1] |= ALARM_ENABLE_MASK;
- ret = regmap_raw_write(info->rtc, SEC_ALARM0_SEC, data, 8);
+ ret = regmap_raw_write(info->regmap, SEC_ALARM0_SEC, data, 8);
if (ret < 0)
return ret;
ret = s5m8767_rtc_set_alarm_reg(info);
@@ -410,7 +435,7 @@
if (ret < 0)
return ret;
- ret = regmap_raw_write(info->rtc, SEC_ALARM0_SEC, data, 8);
+ ret = regmap_raw_write(info->regmap, SEC_ALARM0_SEC, data, 8);
if (ret < 0)
return ret;
@@ -455,7 +480,7 @@
static void s5m_rtc_enable_wtsr(struct s5m_rtc_info *info, bool enable)
{
int ret;
- ret = regmap_update_bits(info->rtc, SEC_WTSR_SMPL_CNTL,
+ ret = regmap_update_bits(info->regmap, SEC_WTSR_SMPL_CNTL,
WTSR_ENABLE_MASK,
enable ? WTSR_ENABLE_MASK : 0);
if (ret < 0)
@@ -466,7 +491,7 @@
static void s5m_rtc_enable_smpl(struct s5m_rtc_info *info, bool enable)
{
int ret;
- ret = regmap_update_bits(info->rtc, SEC_WTSR_SMPL_CNTL,
+ ret = regmap_update_bits(info->regmap, SEC_WTSR_SMPL_CNTL,
SMPL_ENABLE_MASK,
enable ? SMPL_ENABLE_MASK : 0);
if (ret < 0)
@@ -481,7 +506,7 @@
int ret;
struct rtc_time tm;
- ret = regmap_read(info->rtc, SEC_RTC_UDR_CON, &tp_read);
+ ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &tp_read);
if (ret < 0) {
dev_err(info->dev, "%s: fail to read control reg(%d)\n",
__func__, ret);
@@ -493,7 +518,7 @@
data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
info->rtc_24hr_mode = 1;
- ret = regmap_raw_write(info->rtc, SEC_ALARM0_CONF, data, 2);
+ ret = regmap_raw_write(info->regmap, SEC_ALARM0_CONF, data, 2);
if (ret < 0) {
dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
__func__, ret);
@@ -515,7 +540,7 @@
ret = s5m_rtc_set_time(info->dev, &tm);
}
- ret = regmap_update_bits(info->rtc, SEC_RTC_UDR_CON,
+ ret = regmap_update_bits(info->regmap, SEC_RTC_UDR_CON,
RTC_TCON_MASK, tp_read | RTC_TCON_MASK);
if (ret < 0)
dev_err(info->dev, "%s: fail to update TCON reg(%d)\n",
@@ -542,17 +567,19 @@
info->dev = &pdev->dev;
info->s5m87xx = s5m87xx;
- info->rtc = s5m87xx->rtc;
+ info->regmap = s5m87xx->regmap_rtc;
info->device_type = s5m87xx->device_type;
info->wtsr_smpl = s5m87xx->wtsr_smpl;
switch (pdata->device_type) {
case S5M8763X:
- info->irq = s5m87xx->irq_base + S5M8763_IRQ_ALARM0;
+ info->irq = regmap_irq_get_virq(s5m87xx->irq_data,
+ S5M8763_IRQ_ALARM0);
break;
case S5M8767X:
- info->irq = s5m87xx->irq_base + S5M8767_IRQ_RTCA1;
+ info->irq = regmap_irq_get_virq(s5m87xx->irq_data,
+ S5M8767_IRQ_RTCA1);
break;
default:
@@ -596,7 +623,7 @@
if (info->wtsr_smpl) {
for (i = 0; i < 3; i++) {
s5m_rtc_enable_wtsr(info, false);
- regmap_read(info->rtc, SEC_WTSR_SMPL_CNTL, &val);
+ regmap_read(info->regmap, SEC_WTSR_SMPL_CNTL, &val);
pr_debug("%s: WTSR_SMPL reg(0x%02x)\n", __func__, val);
if (val & WTSR_ENABLE_MASK)
pr_emerg("%s: fail to disable WTSR\n",
@@ -612,6 +639,30 @@
s5m_rtc_enable_smpl(info, false);
}
+static int s5m_rtc_resume(struct device *dev)
+{
+ struct s5m_rtc_info *info = dev_get_drvdata(dev);
+ int ret = 0;
+
+ if (device_may_wakeup(dev))
+ ret = disable_irq_wake(info->irq);
+
+ return ret;
+}
+
+static int s5m_rtc_suspend(struct device *dev)
+{
+ struct s5m_rtc_info *info = dev_get_drvdata(dev);
+ int ret = 0;
+
+ if (device_may_wakeup(dev))
+ ret = enable_irq_wake(info->irq);
+
+ return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(s5m_rtc_pm_ops, s5m_rtc_suspend, s5m_rtc_resume);
+
static const struct platform_device_id s5m_rtc_id[] = {
{ "s5m-rtc", 0 },
};
@@ -620,6 +671,7 @@
.driver = {
.name = "s5m-rtc",
.owner = THIS_MODULE,
+ .pm = &s5m_rtc_pm_ops,
},
.probe = s5m_rtc_probe,
.shutdown = s5m_rtc_shutdown,
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 28955d4..124fc43 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -292,16 +292,20 @@
{
struct proc_dir_entry *pde = PDE(file_inode(file));
unsigned long rv = -EIO;
- unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
- unsigned long, unsigned long) = NULL;
+
if (use_pde(pde)) {
+ typeof(proc_reg_get_unmapped_area) *get_area;
+
+ get_area = pde->proc_fops->get_unmapped_area;
#ifdef CONFIG_MMU
- get_area = current->mm->get_unmapped_area;
+ if (!get_area)
+ get_area = current->mm->get_unmapped_area;
#endif
- if (pde->proc_fops->get_unmapped_area)
- get_area = pde->proc_fops->get_unmapped_area;
+
if (get_area)
rv = get_area(file, orig_addr, len, pgoff, flags);
+ else
+ rv = orig_addr;
unuse_pde(pde);
}
return rv;
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 9649ff0..bd7e987 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -142,7 +142,10 @@
return 0;
}
-#define isolate_huge_page(p, l) false
+static inline bool isolate_huge_page(struct page *page, struct list_head *list)
+{
+ return false;
+}
#define putback_active_hugepage(p) do {} while (0)
#define is_hugepage_active(x) false
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d4e98d1..ecb8754 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -193,7 +193,8 @@
(__x < 0) ? -__x : __x; \
})
-#if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
+#if defined(CONFIG_MMU) && \
+ (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
void might_fault(void);
#else
static inline void might_fault(void) { }
diff --git a/include/linux/mfd/samsung/core.h b/include/linux/mfd/samsung/core.h
index 2d0c907..cab2dd2 100644
--- a/include/linux/mfd/samsung/core.h
+++ b/include/linux/mfd/samsung/core.h
@@ -39,7 +39,8 @@
struct sec_pmic_dev {
struct device *dev;
struct sec_platform_data *pdata;
- struct regmap *regmap;
+ struct regmap *regmap_pmic;
+ struct regmap *regmap_rtc;
struct i2c_client *i2c;
struct i2c_client *rtc;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bccd5a6..33a5dc4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1481,8 +1481,18 @@
pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
VM_BUG_ON(!pmd_none(*new_pmd));
set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd));
- if (new_ptl != old_ptl)
+ if (new_ptl != old_ptl) {
+ pgtable_t pgtable;
+
+ /*
+ * Move preallocated PTE page table if new_pmd is on
+ * different PMD page table.
+ */
+ pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
+ pgtable_trans_huge_deposit(mm, new_pmd, pgtable);
+
spin_unlock(new_ptl);
+ }
spin_unlock(old_ptl);
}
out:
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f1a0ae6..bf5e894 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2694,7 +2694,10 @@
goto bypass;
if (unlikely(task_in_memcg_oom(current)))
- goto bypass;
+ goto nomem;
+
+ if (gfp_mask & __GFP_NOFAIL)
+ oom = false;
/*
* We always charge the cgroup the mm_struct belongs to.
@@ -6352,6 +6355,42 @@
static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ /*
+ * XXX: css_offline() would be where we should reparent all
+ * memory to prepare the cgroup for destruction. However,
+ * memcg does not do css_tryget() and res_counter charging
+ * under the same RCU lock region, which means that charging
+ * could race with offlining. Offlining only happens to
+ * cgroups with no tasks in them but charges can show up
+ * without any tasks from the swapin path when the target
+ * memcg is looked up from the swapout record and not from the
+ * current task as it usually is. A race like this can leak
+ * charges and put pages with stale cgroup pointers into
+ * circulation:
+ *
+ * #0 #1
+ * lookup_swap_cgroup_id()
+ * rcu_read_lock()
+ * mem_cgroup_lookup()
+ * css_tryget()
+ * rcu_read_unlock()
+ * disable css_tryget()
+ * call_rcu()
+ * offline_css()
+ * reparent_charges()
+ * res_counter_charge()
+ * css_put()
+ * css_free()
+ * pc->mem_cgroup = dead memcg
+ * add page to lru
+ *
+ * The bulk of the charges are still moved in offline_css() to
+ * avoid pinning a lot of pages in case a long-term reference
+ * like a swapout record is deferring the css_free() to long
+ * after offlining. But this makes sure we catch any charges
+ * made after offlining:
+ */
+ mem_cgroup_reparent_charges(memcg);
memcg_destroy_kmem(memcg);
__mem_cgroup_free(memcg);
