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Message-ID: <20190723150335.291cff59@gandalf.local.home>
Date: Tue, 23 Jul 2019 15:03:35 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>,
linux-rt-users <linux-rt-users@...r.kernel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Carsten Emde <C.Emde@...dl.org>,
John Kacur <jkacur@...hat.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Julia Cartwright <julia@...com>,
Daniel Wagner <wagi@...om.org>, tom.zanussi@...ux.intel.com
Subject: [ANNOUNCE] 4.19.59-rt24
Dear RT Folks,
I'm pleased to announce the 4.19.59-rt24 stable release.
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git
branch: v4.19-rt
Head SHA1: dd209b062b86dd951cf1da93f20aa497fe99d52d
Or to build 4.19.59-rt24 directly, the following patches should be applied:
http://www.kernel.org/pub/linux/kernel/v4.x/linux-4.19.tar.xz
http://www.kernel.org/pub/linux/kernel/v4.x/patch-4.19.59.xz
http://www.kernel.org/pub/linux/kernel/projects/rt/4.19/patch-4.19.59-rt24.patch.xz
You can also build from 4.19.59-rt23 by applying the incremental patch:
http://www.kernel.org/pub/linux/kernel/projects/rt/4.19/incr/patch-4.19.59-rt23-rt24.patch.xz
Enjoy,
-- Steve
Changes from v4.19.59-rt23:
---
Luis Claudio R. Goncalves (1):
mm/zswap: Do not disable preemption in zswap_frontswap_store()
Sebastian Andrzej Siewior (12):
kthread: add a global worker thread.
genirq: Do not invoke the affinity callback via a workqueue on RT
genirq: Handle missing work_struct in irq_set_affinity_notifier()
arm: imx6: cpuidle: Use raw_spinlock_t
rcu: Don't allow to change rcu_normal_after_boot on RT
sched/core: Drop a preempt_disable_rt() statement
timers: Redo the notification of canceling timers on -RT
Revert "futex: Ensure lock/unlock symetry versus pi_lock and hash bucket lock"
Revert "futex: Fix bug on when a requeued RT task times out"
Revert "rtmutex: Handle the various new futex race conditions"
Revert "futex: workaround migrate_disable/enable in different context"
futex: Make the futex_hash_bucket lock raw
Steven Rostedt (VMware) (1):
Linux 4.19.59-rt24
Thomas Gleixner (1):
futex: Delay deallocation of pi_state
kbuild test robot (1):
pci/switchtec: fix stream_open.cocci warnings
----
arch/arm/mach-imx/cpuidle-imx6q.c | 10 +-
drivers/block/loop.c | 2 +-
drivers/pci/switch/switchtec.c | 2 +-
drivers/spi/spi-rockchip.c | 1 +
fs/timerfd.c | 5 +-
include/linux/blk-cgroup.h | 2 +-
include/linux/hrtimer.h | 17 +--
include/linux/interrupt.h | 5 +-
include/linux/kthread-cgroup.h | 17 +++
include/linux/kthread.h | 17 ++-
include/linux/posix-timers.h | 1 +
init/main.c | 1 +
kernel/futex.c | 231 ++++++++++++++++----------------------
kernel/irq/manage.c | 24 ++--
kernel/kthread.c | 14 +++
kernel/locking/rtmutex.c | 65 +----------
kernel/locking/rtmutex_common.h | 3 -
kernel/rcu/update.c | 2 +
kernel/sched/core.c | 9 +-
kernel/time/alarmtimer.c | 2 +-
kernel/time/hrtimer.c | 36 ++----
kernel/time/itimer.c | 2 +-
kernel/time/posix-cpu-timers.c | 23 ++++
kernel/time/posix-timers.c | 69 +++++-------
kernel/time/posix-timers.h | 2 +
kernel/time/timer.c | 96 ++++++++--------
localversion-rt | 2 +-
mm/zswap.c | 12 +-
28 files changed, 291 insertions(+), 381 deletions(-)
---------------------------
diff --git a/arch/arm/mach-imx/cpuidle-imx6q.c b/arch/arm/mach-imx/cpuidle-imx6q.c
index 326e870d7123..d9ac80aa1eb0 100644
--- a/arch/arm/mach-imx/cpuidle-imx6q.c
+++ b/arch/arm/mach-imx/cpuidle-imx6q.c
@@ -17,22 +17,22 @@
#include "hardware.h"
static int num_idle_cpus = 0;
-static DEFINE_SPINLOCK(cpuidle_lock);
+static DEFINE_RAW_SPINLOCK(cpuidle_lock);
static int imx6q_enter_wait(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
- spin_lock(&cpuidle_lock);
+ raw_spin_lock(&cpuidle_lock);
if (++num_idle_cpus == num_online_cpus())
imx6_set_lpm(WAIT_UNCLOCKED);
- spin_unlock(&cpuidle_lock);
+ raw_spin_unlock(&cpuidle_lock);
cpu_do_idle();
- spin_lock(&cpuidle_lock);
+ raw_spin_lock(&cpuidle_lock);
if (num_idle_cpus-- == num_online_cpus())
imx6_set_lpm(WAIT_CLOCKED);
- spin_unlock(&cpuidle_lock);
+ raw_spin_unlock(&cpuidle_lock);
return index;
}
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f1e63eb7cbca..aa76c816dbb4 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -70,7 +70,7 @@
#include <linux/writeback.h>
#include <linux/completion.h>
#include <linux/highmem.h>
-#include <linux/kthread.h>
+#include <linux/kthread-cgroup.h>
#include <linux/splice.h>
#include <linux/sysfs.h>
#include <linux/miscdevice.h>
diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index 77d4fb86d05b..ea70bc0b06e9 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -360,7 +360,7 @@ static int switchtec_dev_open(struct inode *inode, struct file *filp)
return PTR_ERR(stuser);
filp->private_data = stuser;
- nonseekable_open(inode, filp);
+ stream_open(inode, filp);
dev_dbg(&stdev->dev, "%s: %p\n", __func__, stuser);
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index fdcf3076681b..b56619418cea 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -22,6 +22,7 @@
#include <linux/spi/spi.h>
#include <linux/pm_runtime.h>
#include <linux/scatterlist.h>
+#include <linux/interrupt.h>
#define DRIVER_NAME "rockchip-spi"
diff --git a/fs/timerfd.c b/fs/timerfd.c
index 82d0f52414a6..f845093466be 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -471,10 +471,11 @@ static int do_timerfd_settime(int ufd, int flags,
break;
}
spin_unlock_irq(&ctx->wqh.lock);
+
if (isalarm(ctx))
- hrtimer_wait_for_timer(&ctx->t.alarm.timer);
+ hrtimer_grab_expiry_lock(&ctx->t.alarm.timer);
else
- hrtimer_wait_for_timer(&ctx->t.tmr);
+ hrtimer_grab_expiry_lock(&ctx->t.tmr);
}
/*
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 6d766a19f2bb..0473efda4c65 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -14,7 +14,7 @@
* Nauman Rafique <nauman@...gle.com>
*/
-#include <linux/cgroup.h>
+#include <linux/kthread-cgroup.h>
#include <linux/percpu_counter.h>
#include <linux/seq_file.h>
#include <linux/radix-tree.h>
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 2bdb047c7656..6c4c38186c99 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -22,7 +22,6 @@
#include <linux/percpu.h>
#include <linux/timer.h>
#include <linux/timerqueue.h>
-#include <linux/wait.h>
struct hrtimer_clock_base;
struct hrtimer_cpu_base;
@@ -193,6 +192,8 @@ enum hrtimer_base_type {
* @nr_retries: Total number of hrtimer interrupt retries
* @nr_hangs: Total number of hrtimer interrupt hangs
* @max_hang_time: Maximum time spent in hrtimer_interrupt
+ * @softirq_expiry_lock: Lock which is taken while softirq based hrtimer are
+ * expired
* @expires_next: absolute time of the next event, is required for remote
* hrtimer enqueue; it is the total first expiry time (hard
* and soft hrtimer are taken into account)
@@ -220,12 +221,10 @@ struct hrtimer_cpu_base {
unsigned short nr_hangs;
unsigned int max_hang_time;
#endif
+ spinlock_t softirq_expiry_lock;
ktime_t expires_next;
struct hrtimer *next_timer;
ktime_t softirq_expires_next;
-#ifdef CONFIG_PREEMPT_RT_BASE
- wait_queue_head_t wait;
-#endif
struct hrtimer *softirq_next_timer;
struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
} ____cacheline_aligned;
@@ -426,6 +425,7 @@ static inline void hrtimer_start(struct hrtimer *timer, ktime_t tim,
extern int hrtimer_cancel(struct hrtimer *timer);
extern int hrtimer_try_to_cancel(struct hrtimer *timer);
+extern void hrtimer_grab_expiry_lock(const struct hrtimer *timer);
static inline void hrtimer_start_expires(struct hrtimer *timer,
enum hrtimer_mode mode)
@@ -443,13 +443,6 @@ static inline void hrtimer_restart(struct hrtimer *timer)
hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}
-/* Softirq preemption could deadlock timer removal */
-#ifdef CONFIG_PREEMPT_RT_BASE
- extern void hrtimer_wait_for_timer(const struct hrtimer *timer);
-#else
-# define hrtimer_wait_for_timer(timer) do { cpu_relax(); } while (0)
-#endif
-
/* Query timers: */
extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust);
@@ -475,7 +468,7 @@ static inline int hrtimer_is_queued(struct hrtimer *timer)
* Helper function to check, whether the timer is running the callback
* function
*/
-static inline int hrtimer_callback_running(const struct hrtimer *timer)
+static inline int hrtimer_callback_running(struct hrtimer *timer)
{
return timer->base->running == timer;
}
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 72333899f043..a9321f6429f2 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -13,7 +13,7 @@
#include <linux/hrtimer.h>
#include <linux/kref.h>
#include <linux/workqueue.h>
-#include <linux/swork.h>
+#include <linux/kthread.h>
#include <linux/atomic.h>
#include <asm/ptrace.h>
@@ -228,7 +228,6 @@ extern void resume_device_irqs(void);
* struct irq_affinity_notify - context for notification of IRQ affinity changes
* @irq: Interrupt to which notification applies
* @kref: Reference count, for internal use
- * @swork: Swork item, for internal use
* @work: Work item, for internal use
* @notify: Function to be called on change. This will be
* called in process context.
@@ -241,7 +240,7 @@ struct irq_affinity_notify {
unsigned int irq;
struct kref kref;
#ifdef CONFIG_PREEMPT_RT_BASE
- struct swork_event swork;
+ struct kthread_work work;
#else
struct work_struct work;
#endif
diff --git a/include/linux/kthread-cgroup.h b/include/linux/kthread-cgroup.h
new file mode 100644
index 000000000000..53d34bca9d72
--- /dev/null
+++ b/include/linux/kthread-cgroup.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KTHREAD_CGROUP_H
+#define _LINUX_KTHREAD_CGROUP_H
+#include <linux/kthread.h>
+#include <linux/cgroup.h>
+
+#ifdef CONFIG_BLK_CGROUP
+void kthread_associate_blkcg(struct cgroup_subsys_state *css);
+struct cgroup_subsys_state *kthread_blkcg(void);
+#else
+static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
+static inline struct cgroup_subsys_state *kthread_blkcg(void)
+{
+ return NULL;
+}
+#endif
+#endif
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index ad292898f7f2..7cf56eb54103 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -4,7 +4,6 @@
/* Simple interface for creating and stopping kernel threads without mess. */
#include <linux/err.h>
#include <linux/sched.h>
-#include <linux/cgroup.h>
__printf(4, 5)
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
@@ -106,7 +105,7 @@ struct kthread_delayed_work {
};
#define KTHREAD_WORKER_INIT(worker) { \
- .lock = __SPIN_LOCK_UNLOCKED((worker).lock), \
+ .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock), \
.work_list = LIST_HEAD_INIT((worker).work_list), \
.delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
}
@@ -198,14 +197,12 @@ bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
void kthread_destroy_worker(struct kthread_worker *worker);
-#ifdef CONFIG_BLK_CGROUP
-void kthread_associate_blkcg(struct cgroup_subsys_state *css);
-struct cgroup_subsys_state *kthread_blkcg(void);
-#else
-static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
-static inline struct cgroup_subsys_state *kthread_blkcg(void)
+extern struct kthread_worker kthread_global_worker;
+void kthread_init_global_worker(void);
+
+static inline bool kthread_schedule_work(struct kthread_work *work)
{
- return NULL;
+ return kthread_queue_work(&kthread_global_worker, work);
}
-#endif
+
#endif /* _LINUX_KTHREAD_H */
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 0571b498db73..3e6c91bdf2ef 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -15,6 +15,7 @@ struct cpu_timer_list {
u64 expires, incr;
struct task_struct *task;
int firing;
+ int firing_cpu;
};
/*
diff --git a/init/main.c b/init/main.c
index 4a7471606e53..b0e95351c22c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1130,6 +1130,7 @@ static noinline void __init kernel_init_freeable(void)
smp_prepare_cpus(setup_max_cpus);
workqueue_init();
+ kthread_init_global_worker();
init_mm_internals();
diff --git a/kernel/futex.c b/kernel/futex.c
index fe90164aa6ec..688b6fcb79cb 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -240,7 +240,7 @@ struct futex_q {
struct plist_node list;
struct task_struct *task;
- spinlock_t *lock_ptr;
+ raw_spinlock_t *lock_ptr;
union futex_key key;
struct futex_pi_state *pi_state;
struct rt_mutex_waiter *rt_waiter;
@@ -261,7 +261,7 @@ static const struct futex_q futex_q_init = {
*/
struct futex_hash_bucket {
atomic_t waiters;
- spinlock_t lock;
+ raw_spinlock_t lock;
struct plist_head chain;
} ____cacheline_aligned_in_smp;
@@ -822,13 +822,13 @@ static void get_pi_state(struct futex_pi_state *pi_state)
* Drops a reference to the pi_state object and frees or caches it
* when the last reference is gone.
*/
-static void put_pi_state(struct futex_pi_state *pi_state)
+static struct futex_pi_state *__put_pi_state(struct futex_pi_state *pi_state)
{
if (!pi_state)
- return;
+ return NULL;
if (!atomic_dec_and_test(&pi_state->refcount))
- return;
+ return NULL;
/*
* If pi_state->owner is NULL, the owner is most probably dying
@@ -848,9 +848,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
}
- if (current->pi_state_cache) {
- kfree(pi_state);
- } else {
+ if (!current->pi_state_cache) {
/*
* pi_state->list is already empty.
* clear pi_state->owner.
@@ -859,6 +857,30 @@ static void put_pi_state(struct futex_pi_state *pi_state)
pi_state->owner = NULL;
atomic_set(&pi_state->refcount, 1);
current->pi_state_cache = pi_state;
+ pi_state = NULL;
+ }
+ return pi_state;
+}
+
+static void put_pi_state(struct futex_pi_state *pi_state)
+{
+ kfree(__put_pi_state(pi_state));
+}
+
+static void put_pi_state_atomic(struct futex_pi_state *pi_state,
+ struct list_head *to_free)
+{
+ if (__put_pi_state(pi_state))
+ list_add(&pi_state->list, to_free);
+}
+
+static void free_pi_state_list(struct list_head *to_free)
+{
+ struct futex_pi_state *p, *next;
+
+ list_for_each_entry_safe(p, next, to_free, list) {
+ list_del(&p->list);
+ kfree(p);
}
}
@@ -875,6 +897,7 @@ void exit_pi_state_list(struct task_struct *curr)
struct futex_pi_state *pi_state;
struct futex_hash_bucket *hb;
union futex_key key = FUTEX_KEY_INIT;
+ LIST_HEAD(to_free);
if (!futex_cmpxchg_enabled)
return;
@@ -908,7 +931,7 @@ void exit_pi_state_list(struct task_struct *curr)
}
raw_spin_unlock_irq(&curr->pi_lock);
- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
raw_spin_lock(&curr->pi_lock);
/*
@@ -918,10 +941,8 @@ void exit_pi_state_list(struct task_struct *curr)
if (head->next != next) {
/* retain curr->pi_lock for the loop invariant */
raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
- raw_spin_unlock_irq(&curr->pi_lock);
- spin_unlock(&hb->lock);
- raw_spin_lock_irq(&curr->pi_lock);
- put_pi_state(pi_state);
+ raw_spin_unlock(&hb->lock);
+ put_pi_state_atomic(pi_state, &to_free);
continue;
}
@@ -932,7 +953,7 @@ void exit_pi_state_list(struct task_struct *curr)
raw_spin_unlock(&curr->pi_lock);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
rt_mutex_futex_unlock(&pi_state->pi_mutex);
put_pi_state(pi_state);
@@ -940,6 +961,8 @@ void exit_pi_state_list(struct task_struct *curr)
raw_spin_lock_irq(&curr->pi_lock);
}
raw_spin_unlock_irq(&curr->pi_lock);
+
+ free_pi_state_list(&to_free);
}
#endif
@@ -1426,7 +1449,7 @@ static void __unqueue_futex(struct futex_q *q)
{
struct futex_hash_bucket *hb;
- if (WARN_ON_SMP(!q->lock_ptr || !spin_is_locked(q->lock_ptr))
+ if (WARN_ON_SMP(!q->lock_ptr || !raw_spin_is_locked(q->lock_ptr))
|| WARN_ON(plist_node_empty(&q->list)))
return;
@@ -1554,21 +1577,21 @@ static inline void
double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
{
if (hb1 <= hb2) {
- spin_lock(&hb1->lock);
+ raw_spin_lock(&hb1->lock);
if (hb1 < hb2)
- spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING);
+ raw_spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING);
} else { /* hb1 > hb2 */
- spin_lock(&hb2->lock);
- spin_lock_nested(&hb1->lock, SINGLE_DEPTH_NESTING);
+ raw_spin_lock(&hb2->lock);
+ raw_spin_lock_nested(&hb1->lock, SINGLE_DEPTH_NESTING);
}
}
static inline void
double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
{
- spin_unlock(&hb1->lock);
+ raw_spin_unlock(&hb1->lock);
if (hb1 != hb2)
- spin_unlock(&hb2->lock);
+ raw_spin_unlock(&hb2->lock);
}
/*
@@ -1596,7 +1619,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
if (!hb_waiters_pending(hb))
goto out_put_key;
- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);
plist_for_each_entry_safe(this, next, &hb->chain, list) {
if (match_futex (&this->key, &key)) {
@@ -1615,7 +1638,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
}
}
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
wake_up_q(&wake_q);
out_put_key:
put_futex_key(&key);
@@ -1922,6 +1945,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
struct futex_hash_bucket *hb1, *hb2;
struct futex_q *this, *next;
DEFINE_WAKE_Q(wake_q);
+ LIST_HEAD(to_free);
if (nr_wake < 0 || nr_requeue < 0)
return -EINVAL;
@@ -2149,16 +2173,6 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
requeue_pi_wake_futex(this, &key2, hb2);
drop_count++;
continue;
- } else if (ret == -EAGAIN) {
- /*
- * Waiter was woken by timeout or
- * signal and has set pi_blocked_on to
- * PI_WAKEUP_INPROGRESS before we
- * tried to enqueue it on the rtmutex.
- */
- this->pi_state = NULL;
- put_pi_state(pi_state);
- continue;
} else if (ret) {
/*
* rt_mutex_start_proxy_lock() detected a
@@ -2169,7 +2183,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
* object.
*/
this->pi_state = NULL;
- put_pi_state(pi_state);
+ put_pi_state_atomic(pi_state, &to_free);
/*
* We stop queueing more waiters and let user
* space deal with the mess.
@@ -2186,7 +2200,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
* in futex_proxy_trylock_atomic() or in lookup_pi_state(). We
* need to drop it here again.
*/
- put_pi_state(pi_state);
+ put_pi_state_atomic(pi_state, &to_free);
out_unlock:
double_unlock_hb(hb1, hb2);
@@ -2207,6 +2221,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
out_put_key1:
put_futex_key(&key1);
out:
+ free_pi_state_list(&to_free);
return ret ? ret : task_count;
}
@@ -2230,7 +2245,7 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)
q->lock_ptr = &hb->lock;
- spin_lock(&hb->lock); /* implies smp_mb(); (A) */
+ raw_spin_lock(&hb->lock); /* implies smp_mb(); (A) */
return hb;
}
@@ -2238,7 +2253,7 @@ static inline void
queue_unlock(struct futex_hash_bucket *hb)
__releases(&hb->lock)
{
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
hb_waiters_dec(hb);
}
@@ -2277,7 +2292,7 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
__releases(&hb->lock)
{
__queue_me(q, hb);
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
}
/**
@@ -2293,41 +2308,41 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
*/
static int unqueue_me(struct futex_q *q)
{
- spinlock_t *lock_ptr;
+ raw_spinlock_t *lock_ptr;
int ret = 0;
/* In the common case we don't take the spinlock, which is nice. */
retry:
/*
- * q->lock_ptr can change between this read and the following spin_lock.
- * Use READ_ONCE to forbid the compiler from reloading q->lock_ptr and
- * optimizing lock_ptr out of the logic below.
+ * q->lock_ptr can change between this read and the following
+ * raw_spin_lock. Use READ_ONCE to forbid the compiler from reloading
+ * q->lock_ptr and optimizing lock_ptr out of the logic below.
*/
lock_ptr = READ_ONCE(q->lock_ptr);
if (lock_ptr != NULL) {
- spin_lock(lock_ptr);
+ raw_spin_lock(lock_ptr);
/*
* q->lock_ptr can change between reading it and
- * spin_lock(), causing us to take the wrong lock. This
+ * raw_spin_lock(), causing us to take the wrong lock. This
* corrects the race condition.
*
* Reasoning goes like this: if we have the wrong lock,
* q->lock_ptr must have changed (maybe several times)
- * between reading it and the spin_lock(). It can
- * change again after the spin_lock() but only if it was
- * already changed before the spin_lock(). It cannot,
+ * between reading it and the raw_spin_lock(). It can
+ * change again after the raw_spin_lock() but only if it was
+ * already changed before the raw_spin_lock(). It cannot,
* however, change back to the original value. Therefore
* we can detect whether we acquired the correct lock.
*/
if (unlikely(lock_ptr != q->lock_ptr)) {
- spin_unlock(lock_ptr);
+ raw_spin_unlock(lock_ptr);
goto retry;
}
__unqueue_futex(q);
BUG_ON(q->pi_state);
- spin_unlock(lock_ptr);
+ raw_spin_unlock(lock_ptr);
ret = 1;
}
@@ -2343,13 +2358,16 @@ static int unqueue_me(struct futex_q *q)
static void unqueue_me_pi(struct futex_q *q)
__releases(q->lock_ptr)
{
+ struct futex_pi_state *ps;
+
__unqueue_futex(q);
BUG_ON(!q->pi_state);
- put_pi_state(q->pi_state);
+ ps = __put_pi_state(q->pi_state);
q->pi_state = NULL;
- spin_unlock(q->lock_ptr);
+ raw_spin_unlock(q->lock_ptr);
+ kfree(ps);
}
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
@@ -2482,7 +2500,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
*/
handle_err:
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
- spin_unlock(q->lock_ptr);
+ raw_spin_unlock(q->lock_ptr);
switch (err) {
case -EFAULT:
@@ -2500,7 +2518,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
break;
}
- spin_lock(q->lock_ptr);
+ raw_spin_lock(q->lock_ptr);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
/*
@@ -2596,7 +2614,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q,
/*
* The task state is guaranteed to be set before another task can
* wake it. set_current_state() is implemented using smp_store_mb() and
- * queue_me() calls spin_unlock() upon completion, both serializing
+ * queue_me() calls raw_spin_unlock() upon completion, both serializing
* access to the hash list and forcing another memory barrier.
*/
set_current_state(TASK_INTERRUPTIBLE);
@@ -2887,15 +2905,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
* before __rt_mutex_start_proxy_lock() is done.
*/
raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
- /*
- * the migrate_disable() here disables migration in the in_atomic() fast
- * path which is enabled again in the following spin_unlock(). We have
- * one migrate_disable() pending in the slow-path which is reversed
- * after the raw_spin_unlock_irq() where we leave the atomic context.
- */
- migrate_disable();
-
- spin_unlock(q.lock_ptr);
+ raw_spin_unlock(q.lock_ptr);
/*
* __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
* such that futex_unlock_pi() is guaranteed to observe the waiter when
@@ -2903,7 +2913,6 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
*/
ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
- migrate_enable();
if (ret) {
if (ret == 1)
@@ -2917,7 +2926,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);
cleanup:
- spin_lock(q.lock_ptr);
+ raw_spin_lock(q.lock_ptr);
/*
* If we failed to acquire the lock (deadlock/signal/timeout), we must
* first acquire the hb->lock before removing the lock from the
@@ -3018,7 +3027,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
return ret;
hb = hash_futex(&key);
- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);
/*
* Check waiters first. We do not trust user space values at
@@ -3052,21 +3061,11 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
* rt_waiter. Also see the WARN in wake_futex_pi().
*/
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
- /*
- * Magic trickery for now to make the RT migrate disable
- * logic happy. The following spin_unlock() happens with
- * interrupts disabled so the internal migrate_enable()
- * won't undo the migrate_disable() which was issued when
- * locking hb->lock.
- */
- migrate_disable();
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
/* drops pi_state->pi_mutex.wait_lock */
ret = wake_futex_pi(uaddr, uval, pi_state);
- migrate_enable();
-
put_pi_state(pi_state);
/*
@@ -3101,7 +3100,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
* owner.
*/
if ((ret = cmpxchg_futex_value_locked(&curval, uaddr, uval, 0))) {
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
switch (ret) {
case -EFAULT:
goto pi_faulted;
@@ -3121,7 +3120,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
ret = (curval == uval) ? 0 : -EAGAIN;
out_unlock:
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
out_putkey:
put_futex_key(&key);
return ret;
@@ -3237,7 +3236,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
struct hrtimer_sleeper timeout, *to = NULL;
struct futex_pi_state *pi_state = NULL;
struct rt_mutex_waiter rt_waiter;
- struct futex_hash_bucket *hb, *hb2;
+ struct futex_hash_bucket *hb;
union futex_key key2 = FUTEX_KEY_INIT;
struct futex_q q = futex_q_init;
int res, ret;
@@ -3295,55 +3294,20 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
/* Queue the futex_q, drop the hb lock, wait for wakeup. */
futex_wait_queue_me(hb, &q, to);
- /*
- * On RT we must avoid races with requeue and trying to block
- * on two mutexes (hb->lock and uaddr2's rtmutex) by
- * serializing access to pi_blocked_on with pi_lock.
- */
- raw_spin_lock_irq(¤t->pi_lock);
- if (current->pi_blocked_on) {
- /*
- * We have been requeued or are in the process of
- * being requeued.
- */
- raw_spin_unlock_irq(¤t->pi_lock);
- } else {
- /*
- * Setting pi_blocked_on to PI_WAKEUP_INPROGRESS
- * prevents a concurrent requeue from moving us to the
- * uaddr2 rtmutex. After that we can safely acquire
- * (and possibly block on) hb->lock.
- */
- current->pi_blocked_on = PI_WAKEUP_INPROGRESS;
- raw_spin_unlock_irq(¤t->pi_lock);
-
- spin_lock(&hb->lock);
-
- /*
- * Clean up pi_blocked_on. We might leak it otherwise
- * when we succeeded with the hb->lock in the fast
- * path.
- */
- raw_spin_lock_irq(¤t->pi_lock);
- current->pi_blocked_on = NULL;
- raw_spin_unlock_irq(¤t->pi_lock);
-
- ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
- spin_unlock(&hb->lock);
- if (ret)
- goto out_put_keys;
- }
+ raw_spin_lock(&hb->lock);
+ ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
+ raw_spin_unlock(&hb->lock);
+ if (ret)
+ goto out_put_keys;
/*
- * In order to be here, we have either been requeued, are in
- * the process of being requeued, or requeue successfully
- * acquired uaddr2 on our behalf. If pi_blocked_on was
- * non-null above, we may be racing with a requeue. Do not
- * rely on q->lock_ptr to be hb2->lock until after blocking on
- * hb->lock or hb2->lock. The futex_requeue dropped our key1
- * reference and incremented our key2 reference count.
+ * In order for us to be here, we know our q.key == key2, and since
+ * we took the hb->lock above, we also know that futex_requeue() has
+ * completed and we no longer have to concern ourselves with a wakeup
+ * race with the atomic proxy lock acquisition by the requeue code. The
+ * futex_requeue dropped our key1 reference and incremented our key2
+ * reference count.
*/
- hb2 = hash_futex(&key2);
/* Check if the requeue code acquired the second futex for us. */
if (!q.rt_waiter) {
@@ -3352,8 +3316,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
* did a lock-steal - fix up the PI-state in that case.
*/
if (q.pi_state && (q.pi_state->owner != current)) {
- spin_lock(&hb2->lock);
- BUG_ON(&hb2->lock != q.lock_ptr);
+ struct futex_pi_state *ps_free;
+
+ raw_spin_lock(q.lock_ptr);
ret = fixup_pi_state_owner(uaddr2, &q, current);
if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current) {
pi_state = q.pi_state;
@@ -3363,8 +3328,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
* Drop the reference to the pi state which
* the requeue_pi() code acquired for us.
*/
- put_pi_state(q.pi_state);
- spin_unlock(&hb2->lock);
+ ps_free = __put_pi_state(q.pi_state);
+ raw_spin_unlock(q.lock_ptr);
+ kfree(ps_free);
}
} else {
struct rt_mutex *pi_mutex;
@@ -3378,8 +3344,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
pi_mutex = &q.pi_state->pi_mutex;
ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter);
- spin_lock(&hb2->lock);
- BUG_ON(&hb2->lock != q.lock_ptr);
+ raw_spin_lock(q.lock_ptr);
if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter))
ret = 0;
@@ -3816,7 +3781,7 @@ static int __init futex_init(void)
for (i = 0; i < futex_hashsize; i++) {
atomic_set(&futex_queues[i].waiters, 0);
plist_head_init(&futex_queues[i].chain);
- spin_lock_init(&futex_queues[i].lock);
+ raw_spin_lock_init(&futex_queues[i].lock);
}
return 0;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 7f4041357d2f..b2736d7d863b 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -261,7 +261,7 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
kref_get(&desc->affinity_notify->kref);
#ifdef CONFIG_PREEMPT_RT_BASE
- swork_queue(&desc->affinity_notify->swork);
+ kthread_schedule_work(&desc->affinity_notify->work);
#else
schedule_work(&desc->affinity_notify->work);
#endif
@@ -326,21 +326,11 @@ static void _irq_affinity_notify(struct irq_affinity_notify *notify)
}
#ifdef CONFIG_PREEMPT_RT_BASE
-static void init_helper_thread(void)
-{
- static int init_sworker_once;
-
- if (init_sworker_once)
- return;
- if (WARN_ON(swork_get()))
- return;
- init_sworker_once = 1;
-}
-static void irq_affinity_notify(struct swork_event *swork)
+static void irq_affinity_notify(struct kthread_work *work)
{
struct irq_affinity_notify *notify =
- container_of(swork, struct irq_affinity_notify, swork);
+ container_of(work, struct irq_affinity_notify, work);
_irq_affinity_notify(notify);
}
@@ -383,8 +373,7 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
notify->irq = irq;
kref_init(¬ify->kref);
#ifdef CONFIG_PREEMPT_RT_BASE
- INIT_SWORK(¬ify->swork, irq_affinity_notify);
- init_helper_thread();
+ kthread_init_work(¬ify->work, irq_affinity_notify);
#else
INIT_WORK(¬ify->work, irq_affinity_notify);
#endif
@@ -396,8 +385,9 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
raw_spin_unlock_irqrestore(&desc->lock, flags);
if (old_notify) {
-#ifndef CONFIG_PREEMPT_RT_BASE
- /* Need to address this for PREEMPT_RT */
+#ifdef CONFIG_PREEMPT_RT_BASE
+ kthread_cancel_work_sync(¬ify->work);
+#else
cancel_work_sync(&old_notify->work);
#endif
kref_put(&old_notify->kref, old_notify->release);
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 5641b55783a6..9db017761a1f 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -20,6 +20,7 @@
#include <linux/freezer.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
+#include <linux/cgroup.h>
#include <trace/events/sched.h>
static DEFINE_SPINLOCK(kthread_create_lock);
@@ -1180,6 +1181,19 @@ void kthread_destroy_worker(struct kthread_worker *worker)
}
EXPORT_SYMBOL(kthread_destroy_worker);
+DEFINE_KTHREAD_WORKER(kthread_global_worker);
+EXPORT_SYMBOL(kthread_global_worker);
+
+__init void kthread_init_global_worker(void)
+{
+ kthread_global_worker.task = kthread_create(kthread_worker_fn,
+ &kthread_global_worker,
+ "kswork");
+ if (WARN_ON(IS_ERR(kthread_global_worker.task)))
+ return;
+ wake_up_process(kthread_global_worker.task);
+}
+
#ifdef CONFIG_BLK_CGROUP
/**
* kthread_associate_blkcg - associate blkcg to current kthread
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 2a9bf2443acc..44a33057a83a 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -142,12 +142,6 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
}
-static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
-{
- return waiter && waiter != PI_WAKEUP_INPROGRESS &&
- waiter != PI_REQUEUE_INPROGRESS;
-}
-
/*
* We can speed up the acquire/release, if there's no debugging state to be
* set up.
@@ -421,8 +415,7 @@ int max_lock_depth = 1024;
static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
{
- return rt_mutex_real_waiter(p->pi_blocked_on) ?
- p->pi_blocked_on->lock : NULL;
+ return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
}
/*
@@ -558,7 +551,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
* reached or the state of the chain has changed while we
* dropped the locks.
*/
- if (!rt_mutex_real_waiter(waiter))
+ if (!waiter)
goto out_unlock_pi;
/*
@@ -1328,22 +1321,6 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
return -EDEADLK;
raw_spin_lock(&task->pi_lock);
- /*
- * In the case of futex requeue PI, this will be a proxy
- * lock. The task will wake unaware that it is enqueueed on
- * this lock. Avoid blocking on two locks and corrupting
- * pi_blocked_on via the PI_WAKEUP_INPROGRESS
- * flag. futex_wait_requeue_pi() sets this when it wakes up
- * before requeue (due to a signal or timeout). Do not enqueue
- * the task if PI_WAKEUP_INPROGRESS is set.
- */
- if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
- raw_spin_unlock(&task->pi_lock);
- return -EAGAIN;
- }
-
- BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
-
waiter->task = task;
waiter->lock = lock;
waiter->prio = task->prio;
@@ -1367,7 +1344,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
rt_mutex_enqueue_pi(owner, waiter);
rt_mutex_adjust_prio(owner);
- if (rt_mutex_real_waiter(owner->pi_blocked_on))
+ if (owner->pi_blocked_on)
chain_walk = 1;
} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
chain_walk = 1;
@@ -1467,7 +1444,7 @@ static void remove_waiter(struct rt_mutex *lock,
{
bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
struct task_struct *owner = rt_mutex_owner(lock);
- struct rt_mutex *next_lock = NULL;
+ struct rt_mutex *next_lock;
lockdep_assert_held(&lock->wait_lock);
@@ -1493,8 +1470,7 @@ static void remove_waiter(struct rt_mutex *lock,
rt_mutex_adjust_prio(owner);
/* Store the lock on which owner is blocked or NULL */
- if (rt_mutex_real_waiter(owner->pi_blocked_on))
- next_lock = task_blocked_on_lock(owner);
+ next_lock = task_blocked_on_lock(owner);
raw_spin_unlock(&owner->pi_lock);
@@ -1530,8 +1506,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
raw_spin_lock_irqsave(&task->pi_lock, flags);
waiter = task->pi_blocked_on;
- if (!rt_mutex_real_waiter(waiter) ||
- rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
+ if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
return;
}
@@ -2350,34 +2325,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
if (try_to_take_rt_mutex(lock, task, NULL))
return 1;
-#ifdef CONFIG_PREEMPT_RT_FULL
- /*
- * In PREEMPT_RT there's an added race.
- * If the task, that we are about to requeue, times out,
- * it can set the PI_WAKEUP_INPROGRESS. This tells the requeue
- * to skip this task. But right after the task sets
- * its pi_blocked_on to PI_WAKEUP_INPROGRESS it can then
- * block on the spin_lock(&hb->lock), which in RT is an rtmutex.
- * This will replace the PI_WAKEUP_INPROGRESS with the actual
- * lock that it blocks on. We *must not* place this task
- * on this proxy lock in that case.
- *
- * To prevent this race, we first take the task's pi_lock
- * and check if it has updated its pi_blocked_on. If it has,
- * we assume that it woke up and we return -EAGAIN.
- * Otherwise, we set the task's pi_blocked_on to
- * PI_REQUEUE_INPROGRESS, so that if the task is waking up
- * it will know that we are in the process of requeuing it.
- */
- raw_spin_lock(&task->pi_lock);
- if (task->pi_blocked_on) {
- raw_spin_unlock(&task->pi_lock);
- return -EAGAIN;
- }
- task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
- raw_spin_unlock(&task->pi_lock);
-#endif
-
/* We enforce deadlock detection for futexes */
ret = task_blocks_on_rt_mutex(lock, waiter, task,
RT_MUTEX_FULL_CHAINWALK);
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 546aaf058b9e..758dc43872e5 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -132,9 +132,6 @@ enum rtmutex_chainwalk {
/*
* PI-futex support (proxy locking functions, etc.):
*/
-#define PI_WAKEUP_INPROGRESS ((struct rt_mutex_waiter *) 1)
-#define PI_REQUEUE_INPROGRESS ((struct rt_mutex_waiter *) 2)
-
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 16d8dba23329..ed75addd3ccd 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -69,7 +69,9 @@ module_param(rcu_expedited, int, 0);
extern int rcu_normal; /* from sysctl */
module_param(rcu_normal, int, 0);
static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
+#ifndef CONFIG_PREEMPT_RT_FULL
module_param(rcu_normal_after_boot, int, 0);
+#endif
#endif /* #ifndef CONFIG_TINY_RCU */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 91a9b2556fb0..1b2503b87473 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -558,14 +558,11 @@ void resched_cpu(int cpu)
*/
int get_nohz_timer_target(void)
{
- int i, cpu;
+ int i, cpu = smp_processor_id();
struct sched_domain *sd;
- preempt_disable_rt();
- cpu = smp_processor_id();
-
if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER))
- goto preempt_en_rt;
+ return cpu;
rcu_read_lock();
for_each_domain(cpu, sd) {
@@ -584,8 +581,6 @@ int get_nohz_timer_target(void)
cpu = housekeeping_any_cpu(HK_FLAG_TIMER);
unlock:
rcu_read_unlock();
-preempt_en_rt:
- preempt_enable_rt();
return cpu;
}
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 966708e8ce14..efa1e433974b 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -436,7 +436,7 @@ int alarm_cancel(struct alarm *alarm)
int ret = alarm_try_to_cancel(alarm);
if (ret >= 0)
return ret;
- hrtimer_wait_for_timer(&alarm->timer);
+ hrtimer_grab_expiry_lock(&alarm->timer);
}
}
EXPORT_SYMBOL_GPL(alarm_cancel);
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index e1040b80362c..4534e7871c8c 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -963,33 +963,16 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
}
EXPORT_SYMBOL_GPL(hrtimer_forward);
-#ifdef CONFIG_PREEMPT_RT_BASE
-# define wake_up_timer_waiters(b) wake_up(&(b)->wait)
-
-/**
- * hrtimer_wait_for_timer - Wait for a running timer
- *
- * @timer: timer to wait for
- *
- * The function waits in case the timers callback function is
- * currently executed on the waitqueue of the timer base. The
- * waitqueue is woken up after the timer callback function has
- * finished execution.
- */
-void hrtimer_wait_for_timer(const struct hrtimer *timer)
+void hrtimer_grab_expiry_lock(const struct hrtimer *timer)
{
struct hrtimer_clock_base *base = timer->base;
- if (base && base->cpu_base &&
- base->index >= HRTIMER_BASE_MONOTONIC_SOFT)
- wait_event(base->cpu_base->wait,
- !(hrtimer_callback_running(timer)));
+ if (base && base->cpu_base) {
+ spin_lock(&base->cpu_base->softirq_expiry_lock);
+ spin_unlock(&base->cpu_base->softirq_expiry_lock);
+ }
}
-#else
-# define wake_up_timer_waiters(b) do { } while (0)
-#endif
-
/*
* enqueue_hrtimer - internal function to (re)start a timer
*
@@ -1224,7 +1207,7 @@ int hrtimer_cancel(struct hrtimer *timer)
if (ret >= 0)
return ret;
- hrtimer_wait_for_timer(timer);
+ hrtimer_grab_expiry_lock(timer);
}
}
EXPORT_SYMBOL_GPL(hrtimer_cancel);
@@ -1528,6 +1511,7 @@ static __latent_entropy void hrtimer_run_softirq(struct softirq_action *h)
unsigned long flags;
ktime_t now;
+ spin_lock(&cpu_base->softirq_expiry_lock);
raw_spin_lock_irqsave(&cpu_base->lock, flags);
now = hrtimer_update_base(cpu_base);
@@ -1537,7 +1521,7 @@ static __latent_entropy void hrtimer_run_softirq(struct softirq_action *h)
hrtimer_update_softirq_timer(cpu_base, true);
raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
- wake_up_timer_waiters(cpu_base);
+ spin_unlock(&cpu_base->softirq_expiry_lock);
}
#ifdef CONFIG_HIGH_RES_TIMERS
@@ -1947,9 +1931,7 @@ int hrtimers_prepare_cpu(unsigned int cpu)
cpu_base->softirq_next_timer = NULL;
cpu_base->expires_next = KTIME_MAX;
cpu_base->softirq_expires_next = KTIME_MAX;
-#ifdef CONFIG_PREEMPT_RT_BASE
- init_waitqueue_head(&cpu_base->wait);
-#endif
+ spin_lock_init(&cpu_base->softirq_expiry_lock);
return 0;
}
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index 55b0e58368bf..a5ff222df4c7 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -215,7 +215,7 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
/* We are sharing ->siglock with it_real_fn() */
if (hrtimer_try_to_cancel(timer) < 0) {
spin_unlock_irq(&tsk->sighand->siglock);
- hrtimer_wait_for_timer(&tsk->signal->real_timer);
+ hrtimer_grab_expiry_lock(timer);
goto again;
}
expires = timeval_to_ktime(value->it_value);
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index baeeaef3b721..59ceedbb03f0 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -789,6 +789,7 @@ check_timers_list(struct list_head *timers,
return t->expires;
t->firing = 1;
+ t->firing_cpu = smp_processor_id();
list_move_tail(&t->entry, firing);
}
@@ -1134,6 +1135,20 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
return 0;
}
+static DEFINE_PER_CPU(spinlock_t, cpu_timer_expiry_lock) = __SPIN_LOCK_UNLOCKED(cpu_timer_expiry_lock);
+
+void cpu_timers_grab_expiry_lock(struct k_itimer *timer)
+{
+ int cpu = timer->it.cpu.firing_cpu;
+
+ if (cpu >= 0) {
+ spinlock_t *expiry_lock = per_cpu_ptr(&cpu_timer_expiry_lock, cpu);
+
+ spin_lock_irq(expiry_lock);
+ spin_unlock_irq(expiry_lock);
+ }
+}
+
/*
* This is called from the timer interrupt handler. The irq handler has
* already updated our counts. We need to check if any timers fire now.
@@ -1144,6 +1159,7 @@ static void __run_posix_cpu_timers(struct task_struct *tsk)
LIST_HEAD(firing);
struct k_itimer *timer, *next;
unsigned long flags;
+ spinlock_t *expiry_lock;
/*
* The fast path checks that there are no expired thread or thread
@@ -1152,6 +1168,9 @@ static void __run_posix_cpu_timers(struct task_struct *tsk)
if (!fastpath_timer_check(tsk))
return;
+ expiry_lock = this_cpu_ptr(&cpu_timer_expiry_lock);
+ spin_lock(expiry_lock);
+
if (!lock_task_sighand(tsk, &flags))
return;
/*
@@ -1186,6 +1205,7 @@ static void __run_posix_cpu_timers(struct task_struct *tsk)
list_del_init(&timer->it.cpu.entry);
cpu_firing = timer->it.cpu.firing;
timer->it.cpu.firing = 0;
+ timer->it.cpu.firing_cpu = -1;
/*
* The firing flag is -1 if we collided with a reset
* of the timer, which already reported this
@@ -1195,6 +1215,7 @@ static void __run_posix_cpu_timers(struct task_struct *tsk)
cpu_timer_fire(timer);
spin_unlock(&timer->it_lock);
}
+ spin_unlock(expiry_lock);
}
#ifdef CONFIG_PREEMPT_RT_BASE
@@ -1460,6 +1481,8 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
spin_unlock_irq(&timer.it_lock);
while (error == TIMER_RETRY) {
+
+ cpu_timers_grab_expiry_lock(&timer);
/*
* We need to handle case when timer was or is in the
* middle of firing. In other cases we already freed
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index a5ec421e3437..c7e97d421590 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -821,25 +821,20 @@ static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
}
-/*
- * Protected by RCU!
- */
-static void timer_wait_for_callback(const struct k_clock *kc, struct k_itimer *timr)
+static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
{
-#ifdef CONFIG_PREEMPT_RT_FULL
- if (kc->timer_arm == common_hrtimer_arm)
- hrtimer_wait_for_timer(&timr->it.real.timer);
- else if (kc == &alarm_clock)
- hrtimer_wait_for_timer(&timr->it.alarm.alarmtimer.timer);
- else
- /* FIXME: Whacky hack for posix-cpu-timers */
- schedule_timeout(1);
-#endif
+ return hrtimer_try_to_cancel(&timr->it.real.timer);
}
-static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
+static void timer_wait_for_callback(const struct k_clock *kc, struct k_itimer *timer)
{
- return hrtimer_try_to_cancel(&timr->it.real.timer);
+ if (kc->timer_arm == common_hrtimer_arm)
+ hrtimer_grab_expiry_lock(&timer->it.real.timer);
+ else if (kc == &alarm_clock)
+ hrtimer_grab_expiry_lock(&timer->it.alarm.alarmtimer.timer);
+ else
+ /* posix-cpu-timers */
+ cpu_timers_grab_expiry_lock(timer);
}
/* Set a POSIX.1b interval timer. */
@@ -901,21 +896,21 @@ static int do_timer_settime(timer_t timer_id, int flags,
if (!timr)
return -EINVAL;
- rcu_read_lock();
kc = timr->kclock;
if (WARN_ON_ONCE(!kc || !kc->timer_set))
error = -EINVAL;
else
error = kc->timer_set(timr, flags, new_spec64, old_spec64);
- unlock_timer(timr, flag);
if (error == TIMER_RETRY) {
+ rcu_read_lock();
+ unlock_timer(timr, flag);
timer_wait_for_callback(kc, timr);
- old_spec64 = NULL; // We already got the old time...
rcu_read_unlock();
+ old_spec64 = NULL; // We already got the old time...
goto retry;
}
- rcu_read_unlock();
+ unlock_timer(timr, flag);
return error;
}
@@ -977,13 +972,21 @@ int common_timer_del(struct k_itimer *timer)
return 0;
}
-static inline int timer_delete_hook(struct k_itimer *timer)
+static int timer_delete_hook(struct k_itimer *timer)
{
const struct k_clock *kc = timer->kclock;
+ int ret;
if (WARN_ON_ONCE(!kc || !kc->timer_del))
return -EINVAL;
- return kc->timer_del(timer);
+ ret = kc->timer_del(timer);
+ if (ret == TIMER_RETRY) {
+ rcu_read_lock();
+ spin_unlock_irq(&timer->it_lock);
+ timer_wait_for_callback(kc, timer);
+ rcu_read_unlock();
+ }
+ return ret;
}
/* Delete a POSIX.1b interval timer. */
@@ -997,15 +1000,8 @@ SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
if (!timer)
return -EINVAL;
- rcu_read_lock();
- if (timer_delete_hook(timer) == TIMER_RETRY) {
- unlock_timer(timer, flags);
- timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
- timer);
- rcu_read_unlock();
+ if (timer_delete_hook(timer) == TIMER_RETRY)
goto retry_delete;
- }
- rcu_read_unlock();
spin_lock(¤t->sighand->siglock);
list_del(&timer->list);
@@ -1031,20 +1027,9 @@ static void itimer_delete(struct k_itimer *timer)
retry_delete:
spin_lock_irqsave(&timer->it_lock, flags);
- /* On RT we can race with a deletion */
- if (!timer->it_signal) {
- unlock_timer(timer, flags);
- return;
- }
-
- if (timer_delete_hook(timer) == TIMER_RETRY) {
- rcu_read_lock();
- unlock_timer(timer, flags);
- timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
- timer);
- rcu_read_unlock();
+ if (timer_delete_hook(timer) == TIMER_RETRY)
goto retry_delete;
- }
+
list_del(&timer->list);
/*
* This keeps any tasks waiting on the spin lock from thinking
diff --git a/kernel/time/posix-timers.h b/kernel/time/posix-timers.h
index ddb21145211a..725bd230a8db 100644
--- a/kernel/time/posix-timers.h
+++ b/kernel/time/posix-timers.h
@@ -32,6 +32,8 @@ extern const struct k_clock clock_process;
extern const struct k_clock clock_thread;
extern const struct k_clock alarm_clock;
+extern void cpu_timers_grab_expiry_lock(struct k_itimer *timer);
+
int posix_timer_event(struct k_itimer *timr, int si_private);
void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting);
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 781483c76b17..d6289d8df06b 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -44,7 +44,6 @@
#include <linux/sched/debug.h>
#include <linux/slab.h>
#include <linux/compat.h>
-#include <linux/swait.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
@@ -198,9 +197,7 @@ EXPORT_SYMBOL(jiffies_64);
struct timer_base {
raw_spinlock_t lock;
struct timer_list *running_timer;
-#ifdef CONFIG_PREEMPT_RT_FULL
- struct swait_queue_head wait_for_running_timer;
-#endif
+ spinlock_t expiry_lock;
unsigned long clk;
unsigned long next_expiry;
unsigned int cpu;
@@ -1189,33 +1186,6 @@ void add_timer_on(struct timer_list *timer, int cpu)
}
EXPORT_SYMBOL_GPL(add_timer_on);
-#ifdef CONFIG_PREEMPT_RT_FULL
-/*
- * Wait for a running timer
- */
-static void wait_for_running_timer(struct timer_list *timer)
-{
- struct timer_base *base;
- u32 tf = timer->flags;
-
- if (tf & TIMER_MIGRATING)
- return;
-
- base = get_timer_base(tf);
- swait_event_exclusive(base->wait_for_running_timer,
- base->running_timer != timer);
-}
-
-# define wakeup_timer_waiters(b) swake_up_all(&(b)->wait_for_running_timer)
-#else
-static inline void wait_for_running_timer(struct timer_list *timer)
-{
- cpu_relax();
-}
-
-# define wakeup_timer_waiters(b) do { } while (0)
-#endif
-
/**
* del_timer - deactivate a timer.
* @timer: the timer to be deactivated
@@ -1245,14 +1215,8 @@ int del_timer(struct timer_list *timer)
}
EXPORT_SYMBOL(del_timer);
-/**
- * try_to_del_timer_sync - Try to deactivate a timer
- * @timer: timer to delete
- *
- * This function tries to deactivate a timer. Upon successful (ret >= 0)
- * exit the timer is not queued and the handler is not running on any CPU.
- */
-int try_to_del_timer_sync(struct timer_list *timer)
+static int __try_to_del_timer_sync(struct timer_list *timer,
+ struct timer_base **basep)
{
struct timer_base *base;
unsigned long flags;
@@ -1260,7 +1224,7 @@ int try_to_del_timer_sync(struct timer_list *timer)
debug_assert_init(timer);
- base = lock_timer_base(timer, &flags);
+ *basep = base = lock_timer_base(timer, &flags);
if (base->running_timer != timer)
ret = detach_if_pending(timer, base, true);
@@ -1269,9 +1233,42 @@ int try_to_del_timer_sync(struct timer_list *timer)
return ret;
}
+
+/**
+ * try_to_del_timer_sync - Try to deactivate a timer
+ * @timer: timer to delete
+ *
+ * This function tries to deactivate a timer. Upon successful (ret >= 0)
+ * exit the timer is not queued and the handler is not running on any CPU.
+ */
+int try_to_del_timer_sync(struct timer_list *timer)
+{
+ struct timer_base *base;
+
+ return __try_to_del_timer_sync(timer, &base);
+}
EXPORT_SYMBOL(try_to_del_timer_sync);
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
+static int __del_timer_sync(struct timer_list *timer)
+{
+ struct timer_base *base;
+ int ret;
+
+ for (;;) {
+ ret = __try_to_del_timer_sync(timer, &base);
+ if (ret >= 0)
+ return ret;
+
+ /*
+ * When accessing the lock, timers of base are no longer expired
+ * and so timer is no longer running.
+ */
+ spin_lock(&base->expiry_lock);
+ spin_unlock(&base->expiry_lock);
+ }
+}
+
/**
* del_timer_sync - deactivate a timer and wait for the handler to finish.
* @timer: the timer to be deactivated
@@ -1327,12 +1324,8 @@ int del_timer_sync(struct timer_list *timer)
* could lead to deadlock.
*/
WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE));
- for (;;) {
- int ret = try_to_del_timer_sync(timer);
- if (ret >= 0)
- return ret;
- wait_for_running_timer(timer);
- }
+
+ return __del_timer_sync(timer);
}
EXPORT_SYMBOL(del_timer_sync);
#endif
@@ -1397,11 +1390,15 @@ static void expire_timers(struct timer_base *base, struct hlist_head *head)
raw_spin_unlock(&base->lock);
call_timer_fn(timer, fn);
base->running_timer = NULL;
+ spin_unlock(&base->expiry_lock);
+ spin_lock(&base->expiry_lock);
raw_spin_lock(&base->lock);
} else {
raw_spin_unlock_irq(&base->lock);
call_timer_fn(timer, fn);
base->running_timer = NULL;
+ spin_unlock(&base->expiry_lock);
+ spin_lock(&base->expiry_lock);
raw_spin_lock_irq(&base->lock);
}
}
@@ -1696,6 +1693,7 @@ static inline void __run_timers(struct timer_base *base)
if (!time_after_eq(jiffies, base->clk))
return;
+ spin_lock(&base->expiry_lock);
raw_spin_lock_irq(&base->lock);
/*
@@ -1723,7 +1721,7 @@ static inline void __run_timers(struct timer_base *base)
expire_timers(base, heads + levels);
}
raw_spin_unlock_irq(&base->lock);
- wakeup_timer_waiters(base);
+ spin_unlock(&base->expiry_lock);
}
/*
@@ -1970,9 +1968,7 @@ static void __init init_timer_cpu(int cpu)
base->cpu = cpu;
raw_spin_lock_init(&base->lock);
base->clk = jiffies;
-#ifdef CONFIG_PREEMPT_RT_FULL
- init_swait_queue_head(&base->wait_for_running_timer);
-#endif
+ spin_lock_init(&base->expiry_lock);
}
}
diff --git a/localversion-rt b/localversion-rt
index 9a218ca23053..b2111a212663 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt23
+-rt24
diff --git a/mm/zswap.c b/mm/zswap.c
index cd91fd9d96b8..420225d3ff0b 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -27,6 +27,7 @@
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
+#include <linux/locallock.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/frontswap.h>
@@ -990,6 +991,8 @@ static void zswap_fill_page(void *ptr, unsigned long value)
memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
}
+/* protect zswap_dstmem from concurrency */
+static DEFINE_LOCAL_IRQ_LOCK(zswap_dstmem_lock);
/*********************************
* frontswap hooks
**********************************/
@@ -1066,12 +1069,11 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
}
/* compress */
- dst = get_cpu_var(zswap_dstmem);
- tfm = *get_cpu_ptr(entry->pool->tfm);
+ dst = get_locked_var(zswap_dstmem_lock, zswap_dstmem);
+ tfm = *this_cpu_ptr(entry->pool->tfm);
src = kmap_atomic(page);
ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
kunmap_atomic(src);
- put_cpu_ptr(entry->pool->tfm);
if (ret) {
ret = -EINVAL;
goto put_dstmem;
@@ -1094,7 +1096,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
memcpy(buf, &zhdr, hlen);
memcpy(buf + hlen, dst, dlen);
zpool_unmap_handle(entry->pool->zpool, handle);
- put_cpu_var(zswap_dstmem);
+ put_locked_var(zswap_dstmem_lock, zswap_dstmem);
/* populate entry */
entry->offset = offset;
@@ -1122,7 +1124,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
return 0;
put_dstmem:
- put_cpu_var(zswap_dstmem);
+ put_locked_var(zswap_dstmem_lock, zswap_dstmem);
zswap_pool_put(entry->pool);
freepage:
zswap_entry_cache_free(entry);
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