Adding debian version 4.19.249-2.debian/4.19.249-2debian

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 582 insertions, 0 deletions

diff --git a/debian/patches-rt/0145-rtmutex-add-rwlock-implementation-based-on-rtmutex.patch b/debian/patches-rt/0145-rtmutex-add-rwlock-implementation-based-on-rtmutex.patch
new file mode 100644
index 000000000..3045accc9
--- /dev/null
+++ b/debian/patches-rt/0145-rtmutex-add-rwlock-implementation-based-on-rtmutex.patch
@@ -0,0 +1,582 @@
+From f6a36a3573a2474292d6b6e71f206f52212b6cd5 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 17:18:06 +0200
+Subject: [PATCH 145/347] rtmutex: add rwlock implementation based on rtmutex
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+The implementation is bias-based, similar to the rwsem implementation.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rwlock_rt.h       | 119 +++++++++++
+ include/linux/rwlock_types_rt.h |  55 +++++
+ kernel/locking/rwlock-rt.c      | 368 ++++++++++++++++++++++++++++++++
+ 3 files changed, 542 insertions(+)
+ create mode 100644 include/linux/rwlock_rt.h
+ create mode 100644 include/linux/rwlock_types_rt.h
+ create mode 100644 kernel/locking/rwlock-rt.c
+
+diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h
+new file mode 100644
+index 000000000000..a9c4c2ac4d1f
+--- /dev/null
++++ b/include/linux/rwlock_rt.h
+@@ -0,0 +1,119 @@
++#ifndef __LINUX_RWLOCK_RT_H
++#define __LINUX_RWLOCK_RT_H
++
++#ifndef __LINUX_SPINLOCK_H
++#error Do not include directly. Use spinlock.h
++#endif
++
++extern void __lockfunc rt_write_lock(rwlock_t *rwlock);
++extern void __lockfunc rt_read_lock(rwlock_t *rwlock);
++extern int __lockfunc rt_write_trylock(rwlock_t *rwlock);
++extern int __lockfunc rt_read_trylock(rwlock_t *rwlock);
++extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
++extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
++extern int __lockfunc rt_read_can_lock(rwlock_t *rwlock);
++extern int __lockfunc rt_write_can_lock(rwlock_t *rwlock);
++extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
++
++#define read_can_lock(rwlock)		rt_read_can_lock(rwlock)
++#define write_can_lock(rwlock)		rt_write_can_lock(rwlock)
++
++#define read_trylock(lock)	__cond_lock(lock, rt_read_trylock(lock))
++#define write_trylock(lock)	__cond_lock(lock, rt_write_trylock(lock))
++
++static inline int __write_trylock_rt_irqsave(rwlock_t *lock, unsigned long *flags)
++{
++	/* XXX ARCH_IRQ_ENABLED */
++	*flags = 0;
++	return rt_write_trylock(lock);
++}
++
++#define write_trylock_irqsave(lock, flags)		\
++	__cond_lock(lock, __write_trylock_rt_irqsave(lock, &(flags)))
++
++#define read_lock_irqsave(lock, flags)			\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		rt_read_lock(lock);			\
++		flags = 0;				\
++	} while (0)
++
++#define write_lock_irqsave(lock, flags)			\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		rt_write_lock(lock);			\
++		flags = 0;				\
++	} while (0)
++
++#define read_lock(lock)		rt_read_lock(lock)
++
++#define read_lock_bh(lock)				\
++	do {						\
++		local_bh_disable();			\
++		rt_read_lock(lock);			\
++	} while (0)
++
++#define read_lock_irq(lock)	read_lock(lock)
++
++#define write_lock(lock)	rt_write_lock(lock)
++
++#define write_lock_bh(lock)				\
++	do {						\
++		local_bh_disable();			\
++		rt_write_lock(lock);			\
++	} while (0)
++
++#define write_lock_irq(lock)	write_lock(lock)
++
++#define read_unlock(lock)	rt_read_unlock(lock)
++
++#define read_unlock_bh(lock)				\
++	do {						\
++		rt_read_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define read_unlock_irq(lock)	read_unlock(lock)
++
++#define write_unlock(lock)	rt_write_unlock(lock)
++
++#define write_unlock_bh(lock)				\
++	do {						\
++		rt_write_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define write_unlock_irq(lock)	write_unlock(lock)
++
++#define read_unlock_irqrestore(lock, flags)		\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		rt_read_unlock(lock);			\
++	} while (0)
++
++#define write_unlock_irqrestore(lock, flags) \
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		rt_write_unlock(lock);			\
++	} while (0)
++
++#define rwlock_init(rwl)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	__rt_rwlock_init(rwl, #rwl, &__key);		\
++} while (0)
++
++/*
++ * Internal functions made global for CPU pinning
++ */
++void __read_rt_lock(struct rt_rw_lock *lock);
++int __read_rt_trylock(struct rt_rw_lock *lock);
++void __write_rt_lock(struct rt_rw_lock *lock);
++int __write_rt_trylock(struct rt_rw_lock *lock);
++void __read_rt_unlock(struct rt_rw_lock *lock);
++void __write_rt_unlock(struct rt_rw_lock *lock);
++
++#endif
+diff --git a/include/linux/rwlock_types_rt.h b/include/linux/rwlock_types_rt.h
+new file mode 100644
+index 000000000000..546a1f8f1274
+--- /dev/null
++++ b/include/linux/rwlock_types_rt.h
+@@ -0,0 +1,55 @@
++#ifndef __LINUX_RWLOCK_TYPES_RT_H
++#define __LINUX_RWLOCK_TYPES_RT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
++#else
++# define RW_DEP_MAP_INIT(lockname)
++#endif
++
++typedef struct rt_rw_lock rwlock_t;
++
++#define __RW_LOCK_UNLOCKED(name) __RWLOCK_RT_INITIALIZER(name)
++
++#define DEFINE_RWLOCK(name) \
++	rwlock_t name = __RW_LOCK_UNLOCKED(name)
++
++/*
++ * A reader biased implementation primarily for CPU pinning.
++ *
++ * Can be selected as general replacement for the single reader RT rwlock
++ * variant
++ */
++struct rt_rw_lock {
++	struct rt_mutex		rtmutex;
++	atomic_t		readers;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++};
++
++#define READER_BIAS	(1U << 31)
++#define WRITER_BIAS	(1U << 30)
++
++#define __RWLOCK_RT_INITIALIZER(name)					\
++{									\
++	.readers = ATOMIC_INIT(READER_BIAS),				\
++	.rtmutex = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.rtmutex),	\
++	RW_DEP_MAP_INIT(name)						\
++}
++
++void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
++			     struct lock_class_key *key);
++
++#define rwlock_biased_rt_init(rwlock)					\
++	do {								\
++		static struct lock_class_key __key;			\
++									\
++		__rwlock_biased_rt_init((rwlock), #rwlock, &__key);	\
++	} while (0)
++
++#endif
+diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
+new file mode 100644
+index 000000000000..aebb7ce25bc6
+--- /dev/null
++++ b/kernel/locking/rwlock-rt.c
+@@ -0,0 +1,368 @@
++/*
++ */
++#include <linux/sched/debug.h>
++#include <linux/export.h>
++
++#include "rtmutex_common.h"
++#include <linux/rwlock_types_rt.h>
++
++/*
++ * RT-specific reader/writer locks
++ *
++ * write_lock()
++ *  1) Lock lock->rtmutex
++ *  2) Remove the reader BIAS to force readers into the slow path
++ *  3) Wait until all readers have left the critical region
++ *  4) Mark it write locked
++ *
++ * write_unlock()
++ *  1) Remove the write locked marker
++ *  2) Set the reader BIAS so readers can use the fast path again
++ *  3) Unlock lock->rtmutex to release blocked readers
++ *
++ * read_lock()
++ *  1) Try fast path acquisition (reader BIAS is set)
++ *  2) Take lock->rtmutex.wait_lock which protects the writelocked flag
++ *  3) If !writelocked, acquire it for read
++ *  4) If writelocked, block on lock->rtmutex
++ *  5) unlock lock->rtmutex, goto 1)
++ *
++ * read_unlock()
++ *  1) Try fast path release (reader count != 1)
++ *  2) Wake the writer waiting in write_lock()#3
++ *
++ * read_lock()#3 has the consequence, that rw locks on RT are not writer
++ * fair, but writers, which should be avoided in RT tasks (think tasklist
++ * lock), are subject to the rtmutex priority/DL inheritance mechanism.
++ *
++ * It's possible to make the rw locks writer fair by keeping a list of
++ * active readers. A blocked writer would force all newly incoming readers
++ * to block on the rtmutex, but the rtmutex would have to be proxy locked
++ * for one reader after the other. We can't use multi-reader inheritance
++ * because there is no way to support that with
++ * SCHED_DEADLINE. Implementing the one by one reader boosting/handover
++ * mechanism is a major surgery for a very dubious value.
++ *
++ * The risk of writer starvation is there, but the pathological use cases
++ * which trigger it are not necessarily the typical RT workloads.
++ */
++
++void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
++			     struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held semaphore:
++	 */
++	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
++	lockdep_init_map(&lock->dep_map, name, key, 0);
++#endif
++	atomic_set(&lock->readers, READER_BIAS);
++	rt_mutex_init(&lock->rtmutex);
++	lock->rtmutex.save_state = 1;
++}
++
++int __read_rt_trylock(struct rt_rw_lock *lock)
++{
++	int r, old;
++
++	/*
++	 * Increment reader count, if lock->readers < 0, i.e. READER_BIAS is
++	 * set.
++	 */
++	for (r = atomic_read(&lock->readers); r < 0;) {
++		old = atomic_cmpxchg(&lock->readers, r, r + 1);
++		if (likely(old == r))
++			return 1;
++		r = old;
++	}
++	return 0;
++}
++
++void __sched __read_rt_lock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	struct rt_mutex_waiter waiter;
++	unsigned long flags;
++
++	if (__read_rt_trylock(lock))
++		return;
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	/*
++	 * Allow readers as long as the writer has not completely
++	 * acquired the semaphore for write.
++	 */
++	if (atomic_read(&lock->readers) != WRITER_BIAS) {
++		atomic_inc(&lock->readers);
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++		return;
++	}
++
++	/*
++	 * Call into the slow lock path with the rtmutex->wait_lock
++	 * held, so this can't result in the following race:
++	 *
++	 * Reader1		Reader2		Writer
++	 *			read_lock()
++	 *					write_lock()
++	 *					rtmutex_lock(m)
++	 *					swait()
++	 * read_lock()
++	 * unlock(m->wait_lock)
++	 *			read_unlock()
++	 *			swake()
++	 *					lock(m->wait_lock)
++	 *					lock->writelocked=true
++	 *					unlock(m->wait_lock)
++	 *
++	 *					write_unlock()
++	 *					lock->writelocked=false
++	 *					rtmutex_unlock(m)
++	 *			read_lock()
++	 *					write_lock()
++	 *					rtmutex_lock(m)
++	 *					swait()
++	 * rtmutex_lock(m)
++	 *
++	 * That would put Reader1 behind the writer waiting on
++	 * Reader2 to call read_unlock() which might be unbound.
++	 */
++	rt_mutex_init_waiter(&waiter, false);
++	rt_spin_lock_slowlock_locked(m, &waiter, flags);
++	/*
++	 * The slowlock() above is guaranteed to return with the rtmutex is
++	 * now held, so there can't be a writer active. Increment the reader
++	 * count and immediately drop the rtmutex again.
++	 */
++	atomic_inc(&lock->readers);
++	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++	rt_spin_lock_slowunlock(m);
++
++	debug_rt_mutex_free_waiter(&waiter);
++}
++
++void __read_rt_unlock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	struct task_struct *tsk;
++
++	/*
++	 * sem->readers can only hit 0 when a writer is waiting for the
++	 * active readers to leave the critical region.
++	 */
++	if (!atomic_dec_and_test(&lock->readers))
++		return;
++
++	raw_spin_lock_irq(&m->wait_lock);
++	/*
++	 * Wake the writer, i.e. the rtmutex owner. It might release the
++	 * rtmutex concurrently in the fast path, but to clean up the rw
++	 * lock it needs to acquire m->wait_lock. The worst case which can
++	 * happen is a spurious wakeup.
++	 */
++	tsk = rt_mutex_owner(m);
++	if (tsk)
++		wake_up_process(tsk);
++
++	raw_spin_unlock_irq(&m->wait_lock);
++}
++
++static void __write_unlock_common(struct rt_rw_lock *lock, int bias,
++				  unsigned long flags)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++
++	atomic_add(READER_BIAS - bias, &lock->readers);
++	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++	rt_spin_lock_slowunlock(m);
++}
++
++void __sched __write_rt_lock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	struct task_struct *self = current;
++	unsigned long flags;
++
++	/* Take the rtmutex as a first step */
++	__rt_spin_lock(m);
++
++	/* Force readers into slow path */
++	atomic_sub(READER_BIAS, &lock->readers);
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++
++	raw_spin_lock(&self->pi_lock);
++	self->saved_state = self->state;
++	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++	raw_spin_unlock(&self->pi_lock);
++
++	for (;;) {
++		/* Have all readers left the critical region? */
++		if (!atomic_read(&lock->readers)) {
++			atomic_set(&lock->readers, WRITER_BIAS);
++			raw_spin_lock(&self->pi_lock);
++			__set_current_state_no_track(self->saved_state);
++			self->saved_state = TASK_RUNNING;
++			raw_spin_unlock(&self->pi_lock);
++			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++			return;
++		}
++
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++
++		if (atomic_read(&lock->readers) != 0)
++			schedule();
++
++		raw_spin_lock_irqsave(&m->wait_lock, flags);
++
++		raw_spin_lock(&self->pi_lock);
++		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++		raw_spin_unlock(&self->pi_lock);
++	}
++}
++
++int __write_rt_trylock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	unsigned long flags;
++
++	if (!__rt_mutex_trylock(m))
++		return 0;
++
++	atomic_sub(READER_BIAS, &lock->readers);
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	if (!atomic_read(&lock->readers)) {
++		atomic_set(&lock->readers, WRITER_BIAS);
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++		return 1;
++	}
++	__write_unlock_common(lock, 0, flags);
++	return 0;
++}
++
++void __write_rt_unlock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	__write_unlock_common(lock, WRITER_BIAS, flags);
++}
++
++/* Map the reader biased implementation */
++static inline int do_read_rt_trylock(rwlock_t *rwlock)
++{
++	return __read_rt_trylock(rwlock);
++}
++
++static inline int do_write_rt_trylock(rwlock_t *rwlock)
++{
++	return __write_rt_trylock(rwlock);
++}
++
++static inline void do_read_rt_lock(rwlock_t *rwlock)
++{
++	__read_rt_lock(rwlock);
++}
++
++static inline void do_write_rt_lock(rwlock_t *rwlock)
++{
++	__write_rt_lock(rwlock);
++}
++
++static inline void do_read_rt_unlock(rwlock_t *rwlock)
++{
++	__read_rt_unlock(rwlock);
++}
++
++static inline void do_write_rt_unlock(rwlock_t *rwlock)
++{
++	__write_rt_unlock(rwlock);
++}
++
++static inline void do_rwlock_rt_init(rwlock_t *rwlock, const char *name,
++				     struct lock_class_key *key)
++{
++	__rwlock_biased_rt_init(rwlock, name, key);
++}
++
++int __lockfunc rt_read_can_lock(rwlock_t *rwlock)
++{
++	return  atomic_read(&rwlock->readers) < 0;
++}
++
++int __lockfunc rt_write_can_lock(rwlock_t *rwlock)
++{
++	return atomic_read(&rwlock->readers) == READER_BIAS;
++}
++
++/*
++ * The common functions which get wrapped into the rwlock API.
++ */
++int __lockfunc rt_read_trylock(rwlock_t *rwlock)
++{
++	int ret;
++
++	migrate_disable();
++	ret = do_read_rt_trylock(rwlock);
++	if (ret)
++		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
++	else
++		migrate_enable();
++	return ret;
++}
++EXPORT_SYMBOL(rt_read_trylock);
++
++int __lockfunc rt_write_trylock(rwlock_t *rwlock)
++{
++	int ret;
++
++	migrate_disable();
++	ret = do_write_rt_trylock(rwlock);
++	if (ret)
++		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
++	else
++		migrate_enable();
++	return ret;
++}
++EXPORT_SYMBOL(rt_write_trylock);
++
++void __lockfunc rt_read_lock(rwlock_t *rwlock)
++{
++	migrate_disable();
++	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
++	do_read_rt_lock(rwlock);
++}
++EXPORT_SYMBOL(rt_read_lock);
++
++void __lockfunc rt_write_lock(rwlock_t *rwlock)
++{
++	migrate_disable();
++	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
++	do_write_rt_lock(rwlock);
++}
++EXPORT_SYMBOL(rt_write_lock);
++
++void __lockfunc rt_read_unlock(rwlock_t *rwlock)
++{
++	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
++	do_read_rt_unlock(rwlock);
++	migrate_enable();
++}
++EXPORT_SYMBOL(rt_read_unlock);
++
++void __lockfunc rt_write_unlock(rwlock_t *rwlock)
++{
++	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
++	do_write_rt_unlock(rwlock);
++	migrate_enable();
++}
++EXPORT_SYMBOL(rt_write_unlock);
++
++void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
++{
++	do_rwlock_rt_init(rwlock, name, key);
++}
++EXPORT_SYMBOL(__rt_rwlock_init);
+-- 
+2.36.1
+