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

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

1 files changed, 360 insertions, 0 deletions

diff --git a/debian/patches-rt/0190-workqueue-Use-normal-rcu.patch b/debian/patches-rt/0190-workqueue-Use-normal-rcu.patch
new file mode 100644
index 000000000..ca3010992
--- /dev/null
+++ b/debian/patches-rt/0190-workqueue-Use-normal-rcu.patch
@@ -0,0 +1,360 @@
+From 8a58c9e05c039f23a1192df034ad9f56961ba52d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 24 Jul 2013 15:26:54 +0200
+Subject: [PATCH 190/347] workqueue: Use normal rcu
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+There is no need for sched_rcu. The undocumented reason why sched_rcu
+is used is to avoid a few explicit rcu_read_lock()/unlock() pairs by
+abusing the fact that sched_rcu reader side critical sections are also
+protected by preempt or irq disabled regions.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/workqueue.c | 95 +++++++++++++++++++++++++---------------------
+ 1 file changed, 52 insertions(+), 43 deletions(-)
+
+diff --git a/kernel/workqueue.c b/kernel/workqueue.c
+index b1bb6cb5802e..3e2f67b77ab8 100644
+--- a/kernel/workqueue.c
++++ b/kernel/workqueue.c
+@@ -128,7 +128,7 @@ enum {
+  *
+  * PL: wq_pool_mutex protected.
+  *
+- * PR: wq_pool_mutex protected for writes.  Sched-RCU protected for reads.
++ * PR: wq_pool_mutex protected for writes.  RCU protected for reads.
+  *
+  * PW: wq_pool_mutex and wq->mutex protected for writes.  Either for reads.
+  *
+@@ -137,7 +137,7 @@ enum {
+  *
+  * WQ: wq->mutex protected.
+  *
+- * WR: wq->mutex protected for writes.  Sched-RCU protected for reads.
++ * WR: wq->mutex protected for writes.  RCU protected for reads.
+  *
+  * MD: wq_mayday_lock protected.
+  */
+@@ -184,7 +184,7 @@ struct worker_pool {
+ 	atomic_t		nr_running ____cacheline_aligned_in_smp;
+ 
+ 	/*
+-	 * Destruction of pool is sched-RCU protected to allow dereferences
++	 * Destruction of pool is RCU protected to allow dereferences
+ 	 * from get_work_pool().
+ 	 */
+ 	struct rcu_head		rcu;
+@@ -213,7 +213,7 @@ struct pool_workqueue {
+ 	/*
+ 	 * Release of unbound pwq is punted to system_wq.  See put_pwq()
+ 	 * and pwq_unbound_release_workfn() for details.  pool_workqueue
+-	 * itself is also sched-RCU protected so that the first pwq can be
++	 * itself is also RCU protected so that the first pwq can be
+ 	 * determined without grabbing wq->mutex.
+ 	 */
+ 	struct work_struct	unbound_release_work;
+@@ -358,20 +358,20 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
+ #include <trace/events/workqueue.h>
+ 
+ #define assert_rcu_or_pool_mutex()					\
+-	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() &&			\
++	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+ 			 !lockdep_is_held(&wq_pool_mutex),		\
+-			 "sched RCU or wq_pool_mutex should be held")
++			 "RCU or wq_pool_mutex should be held")
+ 
+ #define assert_rcu_or_wq_mutex(wq)					\
+-	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() &&			\
++	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+ 			 !lockdep_is_held(&wq->mutex),			\
+-			 "sched RCU or wq->mutex should be held")
++			 "RCU or wq->mutex should be held")
+ 
+ #define assert_rcu_or_wq_mutex_or_pool_mutex(wq)			\
+-	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() &&			\
++	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+ 			 !lockdep_is_held(&wq->mutex) &&		\
+ 			 !lockdep_is_held(&wq_pool_mutex),		\
+-			 "sched RCU, wq->mutex or wq_pool_mutex should be held")
++			 "RCU, wq->mutex or wq_pool_mutex should be held")
+ 
+ #define for_each_cpu_worker_pool(pool, cpu)				\
+ 	for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0];		\
+@@ -383,7 +383,7 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
+  * @pool: iteration cursor
+  * @pi: integer used for iteration
+  *
+- * This must be called either with wq_pool_mutex held or sched RCU read
++ * This must be called either with wq_pool_mutex held or RCU read
+  * locked.  If the pool needs to be used beyond the locking in effect, the
+  * caller is responsible for guaranteeing that the pool stays online.
+  *
+@@ -415,7 +415,7 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
+  * @pwq: iteration cursor
+  * @wq: the target workqueue
+  *
+- * This must be called either with wq->mutex held or sched RCU read locked.
++ * This must be called either with wq->mutex held or RCU read locked.
+  * If the pwq needs to be used beyond the locking in effect, the caller is
+  * responsible for guaranteeing that the pwq stays online.
+  *
+@@ -551,7 +551,7 @@ static int worker_pool_assign_id(struct worker_pool *pool)
+  * @wq: the target workqueue
+  * @node: the node ID
+  *
+- * This must be called with any of wq_pool_mutex, wq->mutex or sched RCU
++ * This must be called with any of wq_pool_mutex, wq->mutex or RCU
+  * read locked.
+  * If the pwq needs to be used beyond the locking in effect, the caller is
+  * responsible for guaranteeing that the pwq stays online.
+@@ -695,8 +695,8 @@ static struct pool_workqueue *get_work_pwq(struct work_struct *work)
+  * @work: the work item of interest
+  *
+  * Pools are created and destroyed under wq_pool_mutex, and allows read
+- * access under sched-RCU read lock.  As such, this function should be
+- * called under wq_pool_mutex or with preemption disabled.
++ * access under RCU read lock.  As such, this function should be
++ * called under wq_pool_mutex or inside of a rcu_read_lock() region.
+  *
+  * All fields of the returned pool are accessible as long as the above
+  * mentioned locking is in effect.  If the returned pool needs to be used
+@@ -1101,7 +1101,7 @@ static void put_pwq_unlocked(struct pool_workqueue *pwq)
+ {
+ 	if (pwq) {
+ 		/*
+-		 * As both pwqs and pools are sched-RCU protected, the
++		 * As both pwqs and pools are RCU protected, the
+ 		 * following lock operations are safe.
+ 		 */
+ 		spin_lock_irq(&pwq->pool->lock);
+@@ -1229,6 +1229,7 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
+ 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
+ 		return 0;
+ 
++	rcu_read_lock();
+ 	/*
+ 	 * The queueing is in progress, or it is already queued. Try to
+ 	 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
+@@ -1267,10 +1268,12 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
+ 		set_work_pool_and_keep_pending(work, pool->id);
+ 
+ 		spin_unlock(&pool->lock);
++		rcu_read_unlock();
+ 		return 1;
+ 	}
+ 	spin_unlock(&pool->lock);
+ fail:
++	rcu_read_unlock();
+ 	local_irq_restore(*flags);
+ 	if (work_is_canceling(work))
+ 		return -ENOENT;
+@@ -1383,6 +1386,7 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
+ 	if (unlikely(wq->flags & __WQ_DRAINING) &&
+ 	    WARN_ON_ONCE(!is_chained_work(wq)))
+ 		return;
++	rcu_read_lock();
+ retry:
+ 	/* pwq which will be used unless @work is executing elsewhere */
+ 	if (wq->flags & WQ_UNBOUND) {
+@@ -1441,10 +1445,8 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
+ 	/* pwq determined, queue */
+ 	trace_workqueue_queue_work(req_cpu, pwq, work);
+ 
+-	if (WARN_ON(!list_empty(&work->entry))) {
+-		spin_unlock(&pwq->pool->lock);
+-		return;
+-	}
++	if (WARN_ON(!list_empty(&work->entry)))
++		goto out;
+ 
+ 	pwq->nr_in_flight[pwq->work_color]++;
+ 	work_flags = work_color_to_flags(pwq->work_color);
+@@ -1463,7 +1465,9 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
+ 	debug_work_activate(work);
+ 	insert_work(pwq, work, worklist, work_flags);
+ 
++out:
+ 	spin_unlock(&pwq->pool->lock);
++	rcu_read_unlock();
+ }
+ 
+ /**
+@@ -2861,14 +2865,14 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
+ 
+ 	might_sleep();
+ 
+-	local_irq_disable();
++	rcu_read_lock();
+ 	pool = get_work_pool(work);
+ 	if (!pool) {
+-		local_irq_enable();
++		rcu_read_unlock();
+ 		return false;
+ 	}
+ 
+-	spin_lock(&pool->lock);
++	spin_lock_irq(&pool->lock);
+ 	/* see the comment in try_to_grab_pending() with the same code */
+ 	pwq = get_work_pwq(work);
+ 	if (pwq) {
+@@ -2900,10 +2904,11 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
+ 		lock_map_acquire(&pwq->wq->lockdep_map);
+ 		lock_map_release(&pwq->wq->lockdep_map);
+ 	}
+-
++	rcu_read_unlock();
+ 	return true;
+ already_gone:
+ 	spin_unlock_irq(&pool->lock);
++	rcu_read_unlock();
+ 	return false;
+ }
+ 
+@@ -3350,7 +3355,7 @@ static void rcu_free_pool(struct rcu_head *rcu)
+  * put_unbound_pool - put a worker_pool
+  * @pool: worker_pool to put
+  *
+- * Put @pool.  If its refcnt reaches zero, it gets destroyed in sched-RCU
++ * Put @pool.  If its refcnt reaches zero, it gets destroyed in RCU
+  * safe manner.  get_unbound_pool() calls this function on its failure path
+  * and this function should be able to release pools which went through,
+  * successfully or not, init_worker_pool().
+@@ -3404,8 +3409,8 @@ static void put_unbound_pool(struct worker_pool *pool)
+ 	del_timer_sync(&pool->idle_timer);
+ 	del_timer_sync(&pool->mayday_timer);
+ 
+-	/* sched-RCU protected to allow dereferences from get_work_pool() */
+-	call_rcu_sched(&pool->rcu, rcu_free_pool);
++	/* RCU protected to allow dereferences from get_work_pool() */
++	call_rcu(&pool->rcu, rcu_free_pool);
+ }
+ 
+ /**
+@@ -3518,14 +3523,14 @@ static void pwq_unbound_release_workfn(struct work_struct *work)
+ 	put_unbound_pool(pool);
+ 	mutex_unlock(&wq_pool_mutex);
+ 
+-	call_rcu_sched(&pwq->rcu, rcu_free_pwq);
++	call_rcu(&pwq->rcu, rcu_free_pwq);
+ 
+ 	/*
+ 	 * If we're the last pwq going away, @wq is already dead and no one
+ 	 * is gonna access it anymore.  Schedule RCU free.
+ 	 */
+ 	if (is_last)
+-		call_rcu_sched(&wq->rcu, rcu_free_wq);
++		call_rcu(&wq->rcu, rcu_free_wq);
+ }
+ 
+ /**
+@@ -4232,7 +4237,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
+ 		 * The base ref is never dropped on per-cpu pwqs.  Directly
+ 		 * schedule RCU free.
+ 		 */
+-		call_rcu_sched(&wq->rcu, rcu_free_wq);
++		call_rcu(&wq->rcu, rcu_free_wq);
+ 	} else {
+ 		/*
+ 		 * We're the sole accessor of @wq at this point.  Directly
+@@ -4342,7 +4347,8 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
+ 	struct pool_workqueue *pwq;
+ 	bool ret;
+ 
+-	rcu_read_lock_sched();
++	rcu_read_lock();
++	preempt_disable();
+ 
+ 	if (cpu == WORK_CPU_UNBOUND)
+ 		cpu = smp_processor_id();
+@@ -4353,7 +4359,8 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
+ 		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+ 
+ 	ret = !list_empty(&pwq->delayed_works);
+-	rcu_read_unlock_sched();
++	preempt_enable();
++	rcu_read_unlock();
+ 
+ 	return ret;
+ }
+@@ -4379,15 +4386,15 @@ unsigned int work_busy(struct work_struct *work)
+ 	if (work_pending(work))
+ 		ret |= WORK_BUSY_PENDING;
+ 
+-	local_irq_save(flags);
++	rcu_read_lock();
+ 	pool = get_work_pool(work);
+ 	if (pool) {
+-		spin_lock(&pool->lock);
++		spin_lock_irqsave(&pool->lock, flags);
+ 		if (find_worker_executing_work(pool, work))
+ 			ret |= WORK_BUSY_RUNNING;
+-		spin_unlock(&pool->lock);
++		spin_unlock_irqrestore(&pool->lock, flags);
+ 	}
+-	local_irq_restore(flags);
++	rcu_read_unlock();
+ 
+ 	return ret;
+ }
+@@ -4572,7 +4579,7 @@ void show_workqueue_state(void)
+ 	unsigned long flags;
+ 	int pi;
+ 
+-	rcu_read_lock_sched();
++	rcu_read_lock();
+ 
+ 	pr_info("Showing busy workqueues and worker pools:\n");
+ 
+@@ -4637,7 +4644,7 @@ void show_workqueue_state(void)
+ 		touch_nmi_watchdog();
+ 	}
+ 
+-	rcu_read_unlock_sched();
++	rcu_read_unlock();
+ }
+ 
+ /* used to show worker information through /proc/PID/{comm,stat,status} */
+@@ -5024,16 +5031,16 @@ bool freeze_workqueues_busy(void)
+ 		 * nr_active is monotonically decreasing.  It's safe
+ 		 * to peek without lock.
+ 		 */
+-		rcu_read_lock_sched();
++		rcu_read_lock();
+ 		for_each_pwq(pwq, wq) {
+ 			WARN_ON_ONCE(pwq->nr_active < 0);
+ 			if (pwq->nr_active) {
+ 				busy = true;
+-				rcu_read_unlock_sched();
++				rcu_read_unlock();
+ 				goto out_unlock;
+ 			}
+ 		}
+-		rcu_read_unlock_sched();
++		rcu_read_unlock();
+ 	}
+ out_unlock:
+ 	mutex_unlock(&wq_pool_mutex);
+@@ -5235,7 +5242,8 @@ static ssize_t wq_pool_ids_show(struct device *dev,
+ 	const char *delim = "";
+ 	int node, written = 0;
+ 
+-	rcu_read_lock_sched();
++	get_online_cpus();
++	rcu_read_lock();
+ 	for_each_node(node) {
+ 		written += scnprintf(buf + written, PAGE_SIZE - written,
+ 				     "%s%d:%d", delim, node,
+@@ -5243,7 +5251,8 @@ static ssize_t wq_pool_ids_show(struct device *dev,
+ 		delim = " ";
+ 	}
+ 	written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
+-	rcu_read_unlock_sched();
++	rcu_read_unlock();
++	put_online_cpus();
+ 
+ 	return written;
+ }
+-- 
+2.36.1
+