[PATCH 6.6 00/11] 6.6.25-rc1 review

[PATCH 6.6 00/11] 6.6.25-rc1 review

[Greg Kroah-Hartman]

This is the start of the stable review cycle for the 6.6.25 release.
There are 11 patches in this series, all will be posted as a response
to this one.  If anyone has any issues with these being applied, please
let me know.

Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
Anything received after that time might be too late.

The whole patch series can be found in one patch at:
	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
or in the git tree and branch at:
	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Linux 6.6.25-rc1

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue.c: Increase workqueue name length"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Move pwq->max_active to wq->max_active"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Factor out pwq_is_empty()"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Replace pwq_activate_inactive_work() with [__]pwq_activate_work()"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Move nr_active handling into helpers"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Make wq_adjust_max_active() round-robin pwqs while activating"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: RCU protect wq->dfl_pwq and implement accessors for it"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Introduce struct wq_node_nr_active"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Implement system-wide nr_active enforcement for unbound workqueues"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Don't call cpumask_test_cpu() with -1 CPU in wq_update_node_max_active()"

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Revert "workqueue: Shorten events_freezable_power_efficient name"


-------------

Diffstat:

 Makefile                  |   4 +-
 include/linux/workqueue.h |  35 +--
 kernel/workqueue.c        | 757 ++++++++--------------------------------------
 3 files changed, 132 insertions(+), 664 deletions(-)

[PATCH 6.6 01/11] Revert "workqueue: Shorten events_freezable_power_efficient name"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 8b934390272d50ae0e7e320617437a03e5712baa which is
commit 8318d6a6362f5903edb4c904a8dd447e59be4ad1 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -7109,7 +7109,7 @@ void __init workqueue_init_early(void)
 					      WQ_FREEZABLE, 0);
 	system_power_efficient_wq = alloc_workqueue("events_power_efficient",
 					      WQ_POWER_EFFICIENT, 0);
-	system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_pwr_efficient",
+	system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient",
 					      WQ_FREEZABLE | WQ_POWER_EFFICIENT,
 					      0);
 	BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||

[PATCH 6.6 02/11] Revert "workqueue: Dont call cpumask_test_cpu() with -1 CPU in wq_update_node_max_active()"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 7df62b8cca38aa452b508b477b16544cba615084 which is
commit 15930da42f8981dc42c19038042947b475b19f47 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1500,7 +1500,7 @@ static void wq_update_node_max_active(st
 
 	lockdep_assert_held(&wq->mutex);
 
-	if (off_cpu >= 0 && !cpumask_test_cpu(off_cpu, effective))
+	if (!cpumask_test_cpu(off_cpu, effective))
 		off_cpu = -1;
 
 	total_cpus = cpumask_weight_and(effective, cpu_online_mask);

[PATCH 6.6 03/11] Revert "workqueue: Implement system-wide nr_active enforcement for unbound workqueues"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 5a70baec2294e8a7d0fcc4558741c23e752dad5c which is
commit 5797b1c18919cd9c289ded7954383e499f729ce0 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/workqueue.h |   35 ----
 kernel/workqueue.c        |  341 ++++------------------------------------------
 2 files changed, 35 insertions(+), 341 deletions(-)

--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -405,13 +405,6 @@ enum {
 	WQ_MAX_ACTIVE		= 512,	  /* I like 512, better ideas? */
 	WQ_UNBOUND_MAX_ACTIVE	= WQ_MAX_ACTIVE,
 	WQ_DFL_ACTIVE		= WQ_MAX_ACTIVE / 2,
-
-	/*
-	 * Per-node default cap on min_active. Unless explicitly set, min_active
-	 * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see
-	 * workqueue_struct->min_active definition.
-	 */
-	WQ_DFL_MIN_ACTIVE	= 8,
 };
 
 /*
@@ -454,33 +447,11 @@ extern struct workqueue_struct *system_f
  * alloc_workqueue - allocate a workqueue
  * @fmt: printf format for the name of the workqueue
  * @flags: WQ_* flags
- * @max_active: max in-flight work items, 0 for default
+ * @max_active: max in-flight work items per CPU, 0 for default
  * remaining args: args for @fmt
  *
- * For a per-cpu workqueue, @max_active limits the number of in-flight work
- * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be
- * executing at most one work item for the workqueue.
- *
- * For unbound workqueues, @max_active limits the number of in-flight work items
- * for the whole system. e.g. @max_active of 16 indicates that that there can be
- * at most 16 work items executing for the workqueue in the whole system.
- *
- * As sharing the same active counter for an unbound workqueue across multiple
- * NUMA nodes can be expensive, @max_active is distributed to each NUMA node
- * according to the proportion of the number of online CPUs and enforced
- * independently.
- *
- * Depending on online CPU distribution, a node may end up with per-node
- * max_active which is significantly lower than @max_active, which can lead to
- * deadlocks if the per-node concurrency limit is lower than the maximum number
- * of interdependent work items for the workqueue.
- *
- * To guarantee forward progress regardless of online CPU distribution, the
- * concurrency limit on every node is guaranteed to be equal to or greater than
- * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means
- * that the sum of per-node max_active's may be larger than @max_active.
- *
- * For detailed information on %WQ_* flags, please refer to
+ * Allocate a workqueue with the specified parameters.  For detailed
+ * information on WQ_* flags, please refer to
  * Documentation/core-api/workqueue.rst.
  *
  * RETURNS:
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -122,9 +122,6 @@ enum {
  *
  * L: pool->lock protected.  Access with pool->lock held.
  *
- * LN: pool->lock and wq_node_nr_active->lock protected for writes. Either for
- *     reads.
- *
  * K: Only modified by worker while holding pool->lock. Can be safely read by
  *    self, while holding pool->lock or from IRQ context if %current is the
  *    kworker.
@@ -246,18 +243,17 @@ struct pool_workqueue {
 	 * pwq->inactive_works instead of pool->worklist and marked with
 	 * WORK_STRUCT_INACTIVE.
 	 *
-	 * All work items marked with WORK_STRUCT_INACTIVE do not participate in
-	 * nr_active and all work items in pwq->inactive_works are marked with
-	 * WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE work items are
-	 * in pwq->inactive_works. Some of them are ready to run in
-	 * pool->worklist or worker->scheduled. Those work itmes are only struct
-	 * wq_barrier which is used for flush_work() and should not participate
-	 * in nr_active. For non-barrier work item, it is marked with
-	 * WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
+	 * All work items marked with WORK_STRUCT_INACTIVE do not participate
+	 * in pwq->nr_active and all work items in pwq->inactive_works are
+	 * marked with WORK_STRUCT_INACTIVE.  But not all WORK_STRUCT_INACTIVE
+	 * work items are in pwq->inactive_works.  Some of them are ready to
+	 * run in pool->worklist or worker->scheduled.  Those work itmes are
+	 * only struct wq_barrier which is used for flush_work() and should
+	 * not participate in pwq->nr_active.  For non-barrier work item, it
+	 * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
 	 */
 	int			nr_active;	/* L: nr of active works */
 	struct list_head	inactive_works;	/* L: inactive works */
-	struct list_head	pending_node;	/* LN: node on wq_node_nr_active->pending_pwqs */
 	struct list_head	pwqs_node;	/* WR: node on wq->pwqs */
 	struct list_head	mayday_node;	/* MD: node on wq->maydays */
 
@@ -289,19 +285,9 @@ struct wq_device;
  * on each CPU, in an unbound workqueue, max_active applies to the whole system.
  * As sharing a single nr_active across multiple sockets can be very expensive,
  * the counting and enforcement is per NUMA node.
- *
- * The following struct is used to enforce per-node max_active. When a pwq wants
- * to start executing a work item, it should increment ->nr using
- * tryinc_node_nr_active(). If acquisition fails due to ->nr already being over
- * ->max, the pwq is queued on ->pending_pwqs. As in-flight work items finish
- * and decrement ->nr, node_activate_pending_pwq() activates the pending pwqs in
- * round-robin order.
  */
 struct wq_node_nr_active {
-	int			max;		/* per-node max_active */
-	atomic_t		nr;		/* per-node nr_active */
-	raw_spinlock_t		lock;		/* nests inside pool locks */
-	struct list_head	pending_pwqs;	/* LN: pwqs with inactive works */
+	atomic_t		nr;		/* per-node nr_active count */
 };
 
 /*
@@ -324,12 +310,8 @@ struct workqueue_struct {
 	struct worker		*rescuer;	/* MD: rescue worker */
 
 	int			nr_drainers;	/* WQ: drain in progress */
-
-	/* See alloc_workqueue() function comment for info on min/max_active */
 	int			max_active;	/* WO: max active works */
-	int			min_active;	/* WO: min active works */
 	int			saved_max_active; /* WQ: saved max_active */
-	int			saved_min_active; /* WQ: saved min_active */
 
 	struct workqueue_attrs	*unbound_attrs;	/* PW: only for unbound wqs */
 	struct pool_workqueue __rcu *dfl_pwq;   /* PW: only for unbound wqs */
@@ -675,19 +657,6 @@ static struct pool_workqueue *unbound_pw
 				     lockdep_is_held(&wq->mutex));
 }
 
-/**
- * unbound_effective_cpumask - effective cpumask of an unbound workqueue
- * @wq: workqueue of interest
- *
- * @wq->unbound_attrs->cpumask contains the cpumask requested by the user which
- * is masked with wq_unbound_cpumask to determine the effective cpumask. The
- * default pwq is always mapped to the pool with the current effective cpumask.
- */
-static struct cpumask *unbound_effective_cpumask(struct workqueue_struct *wq)
-{
-	return unbound_pwq(wq, -1)->pool->attrs->__pod_cpumask;
-}
-
 static unsigned int work_color_to_flags(int color)
 {
 	return color << WORK_STRUCT_COLOR_SHIFT;
@@ -1483,46 +1452,6 @@ static struct wq_node_nr_active *wq_node
 }
 
 /**
- * wq_update_node_max_active - Update per-node max_actives to use
- * @wq: workqueue to update
- * @off_cpu: CPU that's going down, -1 if a CPU is not going down
- *
- * Update @wq->node_nr_active[]->max. @wq must be unbound. max_active is
- * distributed among nodes according to the proportions of numbers of online
- * cpus. The result is always between @wq->min_active and max_active.
- */
-static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu)
-{
-	struct cpumask *effective = unbound_effective_cpumask(wq);
-	int min_active = READ_ONCE(wq->min_active);
-	int max_active = READ_ONCE(wq->max_active);
-	int total_cpus, node;
-
-	lockdep_assert_held(&wq->mutex);
-
-	if (!cpumask_test_cpu(off_cpu, effective))
-		off_cpu = -1;
-
-	total_cpus = cpumask_weight_and(effective, cpu_online_mask);
-	if (off_cpu >= 0)
-		total_cpus--;
-
-	for_each_node(node) {
-		int node_cpus;
-
-		node_cpus = cpumask_weight_and(effective, cpumask_of_node(node));
-		if (off_cpu >= 0 && cpu_to_node(off_cpu) == node)
-			node_cpus--;
-
-		wq_node_nr_active(wq, node)->max =
-			clamp(DIV_ROUND_UP(max_active * node_cpus, total_cpus),
-			      min_active, max_active);
-	}
-
-	wq_node_nr_active(wq, NUMA_NO_NODE)->max = min_active;
-}
-
-/**
  * get_pwq - get an extra reference on the specified pool_workqueue
  * @pwq: pool_workqueue to get
  *
@@ -1619,98 +1548,35 @@ static bool pwq_activate_work(struct poo
 	return true;
 }
 
-static bool tryinc_node_nr_active(struct wq_node_nr_active *nna)
-{
-	int max = READ_ONCE(nna->max);
-
-	while (true) {
-		int old, tmp;
-
-		old = atomic_read(&nna->nr);
-		if (old >= max)
-			return false;
-		tmp = atomic_cmpxchg_relaxed(&nna->nr, old, old + 1);
-		if (tmp == old)
-			return true;
-	}
-}
-
 /**
  * pwq_tryinc_nr_active - Try to increment nr_active for a pwq
  * @pwq: pool_workqueue of interest
- * @fill: max_active may have increased, try to increase concurrency level
  *
  * Try to increment nr_active for @pwq. Returns %true if an nr_active count is
  * successfully obtained. %false otherwise.
  */
-static bool pwq_tryinc_nr_active(struct pool_workqueue *pwq, bool fill)
+static bool pwq_tryinc_nr_active(struct pool_workqueue *pwq)
 {
 	struct workqueue_struct *wq = pwq->wq;
 	struct worker_pool *pool = pwq->pool;
 	struct wq_node_nr_active *nna = wq_node_nr_active(wq, pool->node);
-	bool obtained = false;
+	bool obtained;
 
 	lockdep_assert_held(&pool->lock);
 
-	if (!nna) {
-		/* per-cpu workqueue, pwq->nr_active is sufficient */
-		obtained = pwq->nr_active < READ_ONCE(wq->max_active);
-		goto out;
-	}
-
-	/*
-	 * Unbound workqueue uses per-node shared nr_active $nna. If @pwq is
-	 * already waiting on $nna, pwq_dec_nr_active() will maintain the
-	 * concurrency level. Don't jump the line.
-	 *
-	 * We need to ignore the pending test after max_active has increased as
-	 * pwq_dec_nr_active() can only maintain the concurrency level but not
-	 * increase it. This is indicated by @fill.
-	 */
-	if (!list_empty(&pwq->pending_node) && likely(!fill))
-		goto out;
-
-	obtained = tryinc_node_nr_active(nna);
-	if (obtained)
-		goto out;
-
-	/*
-	 * Lockless acquisition failed. Lock, add ourself to $nna->pending_pwqs
-	 * and try again. The smp_mb() is paired with the implied memory barrier
-	 * of atomic_dec_return() in pwq_dec_nr_active() to ensure that either
-	 * we see the decremented $nna->nr or they see non-empty
-	 * $nna->pending_pwqs.
-	 */
-	raw_spin_lock(&nna->lock);
-
-	if (list_empty(&pwq->pending_node))
-		list_add_tail(&pwq->pending_node, &nna->pending_pwqs);
-	else if (likely(!fill))
-		goto out_unlock;
-
-	smp_mb();
-
-	obtained = tryinc_node_nr_active(nna);
-
-	/*
-	 * If @fill, @pwq might have already been pending. Being spuriously
-	 * pending in cold paths doesn't affect anything. Let's leave it be.
-	 */
-	if (obtained && likely(!fill))
-		list_del_init(&pwq->pending_node);
+	obtained = pwq->nr_active < READ_ONCE(wq->max_active);
 
-out_unlock:
-	raw_spin_unlock(&nna->lock);
-out:
-	if (obtained)
+	if (obtained) {
 		pwq->nr_active++;
+		if (nna)
+			atomic_inc(&nna->nr);
+	}
 	return obtained;
 }
 
 /**
  * pwq_activate_first_inactive - Activate the first inactive work item on a pwq
  * @pwq: pool_workqueue of interest
- * @fill: max_active may have increased, try to increase concurrency level
  *
  * Activate the first inactive work item of @pwq if available and allowed by
  * max_active limit.
@@ -1718,13 +1584,13 @@ out:
  * Returns %true if an inactive work item has been activated. %false if no
  * inactive work item is found or max_active limit is reached.
  */
-static bool pwq_activate_first_inactive(struct pool_workqueue *pwq, bool fill)
+static bool pwq_activate_first_inactive(struct pool_workqueue *pwq)
 {
 	struct work_struct *work =
 		list_first_entry_or_null(&pwq->inactive_works,
 					 struct work_struct, entry);
 
-	if (work && pwq_tryinc_nr_active(pwq, fill)) {
+	if (work && pwq_tryinc_nr_active(pwq)) {
 		__pwq_activate_work(pwq, work);
 		return true;
 	} else {
@@ -1733,92 +1599,10 @@ static bool pwq_activate_first_inactive(
 }
 
 /**
- * node_activate_pending_pwq - Activate a pending pwq on a wq_node_nr_active
- * @nna: wq_node_nr_active to activate a pending pwq for
- * @caller_pool: worker_pool the caller is locking
- *
- * Activate a pwq in @nna->pending_pwqs. Called with @caller_pool locked.
- * @caller_pool may be unlocked and relocked to lock other worker_pools.
- */
-static void node_activate_pending_pwq(struct wq_node_nr_active *nna,
-				      struct worker_pool *caller_pool)
-{
-	struct worker_pool *locked_pool = caller_pool;
-	struct pool_workqueue *pwq;
-	struct work_struct *work;
-
-	lockdep_assert_held(&caller_pool->lock);
-
-	raw_spin_lock(&nna->lock);
-retry:
-	pwq = list_first_entry_or_null(&nna->pending_pwqs,
-				       struct pool_workqueue, pending_node);
-	if (!pwq)
-		goto out_unlock;
-
-	/*
-	 * If @pwq is for a different pool than @locked_pool, we need to lock
-	 * @pwq->pool->lock. Let's trylock first. If unsuccessful, do the unlock
-	 * / lock dance. For that, we also need to release @nna->lock as it's
-	 * nested inside pool locks.
-	 */
-	if (pwq->pool != locked_pool) {
-		raw_spin_unlock(&locked_pool->lock);
-		locked_pool = pwq->pool;
-		if (!raw_spin_trylock(&locked_pool->lock)) {
-			raw_spin_unlock(&nna->lock);
-			raw_spin_lock(&locked_pool->lock);
-			raw_spin_lock(&nna->lock);
-			goto retry;
-		}
-	}
-
-	/*
-	 * $pwq may not have any inactive work items due to e.g. cancellations.
-	 * Drop it from pending_pwqs and see if there's another one.
-	 */
-	work = list_first_entry_or_null(&pwq->inactive_works,
-					struct work_struct, entry);
-	if (!work) {
-		list_del_init(&pwq->pending_node);
-		goto retry;
-	}
-
-	/*
-	 * Acquire an nr_active count and activate the inactive work item. If
-	 * $pwq still has inactive work items, rotate it to the end of the
-	 * pending_pwqs so that we round-robin through them. This means that
-	 * inactive work items are not activated in queueing order which is fine
-	 * given that there has never been any ordering across different pwqs.
-	 */
-	if (likely(tryinc_node_nr_active(nna))) {
-		pwq->nr_active++;
-		__pwq_activate_work(pwq, work);
-
-		if (list_empty(&pwq->inactive_works))
-			list_del_init(&pwq->pending_node);
-		else
-			list_move_tail(&pwq->pending_node, &nna->pending_pwqs);
-
-		/* if activating a foreign pool, make sure it's running */
-		if (pwq->pool != caller_pool)
-			kick_pool(pwq->pool);
-	}
-
-out_unlock:
-	raw_spin_unlock(&nna->lock);
-	if (locked_pool != caller_pool) {
-		raw_spin_unlock(&locked_pool->lock);
-		raw_spin_lock(&caller_pool->lock);
-	}
-}
-
-/**
  * pwq_dec_nr_active - Retire an active count
  * @pwq: pool_workqueue of interest
  *
  * Decrement @pwq's nr_active and try to activate the first inactive work item.
- * For unbound workqueues, this function may temporarily drop @pwq->pool->lock.
  */
 static void pwq_dec_nr_active(struct pool_workqueue *pwq)
 {
@@ -1838,29 +1622,12 @@ static void pwq_dec_nr_active(struct poo
 	 * inactive work item on @pwq itself.
 	 */
 	if (!nna) {
-		pwq_activate_first_inactive(pwq, false);
+		pwq_activate_first_inactive(pwq);
 		return;
 	}
 
-	/*
-	 * If @pwq is for an unbound workqueue, it's more complicated because
-	 * multiple pwqs and pools may be sharing the nr_active count. When a
-	 * pwq needs to wait for an nr_active count, it puts itself on
-	 * $nna->pending_pwqs. The following atomic_dec_return()'s implied
-	 * memory barrier is paired with smp_mb() in pwq_tryinc_nr_active() to
-	 * guarantee that either we see non-empty pending_pwqs or they see
-	 * decremented $nna->nr.
-	 *
-	 * $nna->max may change as CPUs come online/offline and @pwq->wq's
-	 * max_active gets updated. However, it is guaranteed to be equal to or
-	 * larger than @pwq->wq->min_active which is above zero unless freezing.
-	 * This maintains the forward progress guarantee.
-	 */
-	if (atomic_dec_return(&nna->nr) >= READ_ONCE(nna->max))
-		return;
-
-	if (!list_empty(&nna->pending_pwqs))
-		node_activate_pending_pwq(nna, pool);
+	atomic_dec(&nna->nr);
+	pwq_activate_first_inactive(pwq);
 }
 
 /**
@@ -2181,7 +1948,7 @@ retry:
 	 * @work must also queue behind existing inactive work items to maintain
 	 * ordering when max_active changes. See wq_adjust_max_active().
 	 */
-	if (list_empty(&pwq->inactive_works) && pwq_tryinc_nr_active(pwq, false)) {
+	if (list_empty(&pwq->inactive_works) && pwq_tryinc_nr_active(pwq)) {
 		if (list_empty(&pool->worklist))
 			pool->watchdog_ts = jiffies;
 
@@ -3414,7 +3181,7 @@ static void insert_wq_barrier(struct poo
 
 	barr->task = current;
 
-	/* The barrier work item does not participate in nr_active. */
+	/* The barrier work item does not participate in pwq->nr_active. */
 	work_flags |= WORK_STRUCT_INACTIVE;
 
 	/*
@@ -4330,8 +4097,6 @@ static void free_node_nr_active(struct w
 static void init_node_nr_active(struct wq_node_nr_active *nna)
 {
 	atomic_set(&nna->nr, 0);
-	raw_spin_lock_init(&nna->lock);
-	INIT_LIST_HEAD(&nna->pending_pwqs);
 }
 
 /*
@@ -4571,15 +4336,6 @@ static void pwq_release_workfn(struct kt
 		mutex_unlock(&wq_pool_mutex);
 	}
 
-	if (!list_empty(&pwq->pending_node)) {
-		struct wq_node_nr_active *nna =
-			wq_node_nr_active(pwq->wq, pwq->pool->node);
-
-		raw_spin_lock_irq(&nna->lock);
-		list_del_init(&pwq->pending_node);
-		raw_spin_unlock_irq(&nna->lock);
-	}
-
 	call_rcu(&pwq->rcu, rcu_free_pwq);
 
 	/*
@@ -4605,7 +4361,6 @@ static void init_pwq(struct pool_workque
 	pwq->flush_color = -1;
 	pwq->refcnt = 1;
 	INIT_LIST_HEAD(&pwq->inactive_works);
-	INIT_LIST_HEAD(&pwq->pending_node);
 	INIT_LIST_HEAD(&pwq->pwqs_node);
 	INIT_LIST_HEAD(&pwq->mayday_node);
 	kthread_init_work(&pwq->release_work, pwq_release_workfn);
@@ -4813,9 +4568,6 @@ static void apply_wqattrs_commit(struct
 							ctx->pwq_tbl[cpu]);
 	ctx->dfl_pwq = install_unbound_pwq(ctx->wq, -1, ctx->dfl_pwq);
 
-	/* update node_nr_active->max */
-	wq_update_node_max_active(ctx->wq, -1);
-
 	mutex_unlock(&ctx->wq->mutex);
 }
 
@@ -5089,35 +4841,24 @@ static int init_rescuer(struct workqueue
 static void wq_adjust_max_active(struct workqueue_struct *wq)
 {
 	bool activated;
-	int new_max, new_min;
 
 	lockdep_assert_held(&wq->mutex);
 
 	if ((wq->flags & WQ_FREEZABLE) && workqueue_freezing) {
-		new_max = 0;
-		new_min = 0;
-	} else {
-		new_max = wq->saved_max_active;
-		new_min = wq->saved_min_active;
+		WRITE_ONCE(wq->max_active, 0);
+		return;
 	}
 
-	if (wq->max_active == new_max && wq->min_active == new_min)
+	if (wq->max_active == wq->saved_max_active)
 		return;
 
 	/*
-	 * Update @wq->max/min_active and then kick inactive work items if more
+	 * Update @wq->max_active and then kick inactive work items if more
 	 * active work items are allowed. This doesn't break work item ordering
 	 * because new work items are always queued behind existing inactive
 	 * work items if there are any.
 	 */
-	WRITE_ONCE(wq->max_active, new_max);
-	WRITE_ONCE(wq->min_active, new_min);
-
-	if (wq->flags & WQ_UNBOUND)
-		wq_update_node_max_active(wq, -1);
-
-	if (new_max == 0)
-		return;
+	WRITE_ONCE(wq->max_active, wq->saved_max_active);
 
 	/*
 	 * Round-robin through pwq's activating the first inactive work item
@@ -5132,7 +4873,7 @@ static void wq_adjust_max_active(struct
 
 			/* can be called during early boot w/ irq disabled */
 			raw_spin_lock_irqsave(&pwq->pool->lock, flags);
-			if (pwq_activate_first_inactive(pwq, true)) {
+			if (pwq_activate_first_inactive(pwq)) {
 				activated = true;
 				kick_pool(pwq->pool);
 			}
@@ -5194,9 +4935,7 @@ struct workqueue_struct *alloc_workqueue
 	/* init wq */
 	wq->flags = flags;
 	wq->max_active = max_active;
-	wq->min_active = min(max_active, WQ_DFL_MIN_ACTIVE);
-	wq->saved_max_active = wq->max_active;
-	wq->saved_min_active = wq->min_active;
+	wq->saved_max_active = max_active;
 	mutex_init(&wq->mutex);
 	atomic_set(&wq->nr_pwqs_to_flush, 0);
 	INIT_LIST_HEAD(&wq->pwqs);
@@ -5362,8 +5101,7 @@ EXPORT_SYMBOL_GPL(destroy_workqueue);
  * @wq: target workqueue
  * @max_active: new max_active value.
  *
- * Set max_active of @wq to @max_active. See the alloc_workqueue() function
- * comment.
+ * Set max_active of @wq to @max_active.
  *
  * CONTEXT:
  * Don't call from IRQ context.
@@ -5380,9 +5118,6 @@ void workqueue_set_max_active(struct wor
 
 	wq->flags &= ~__WQ_ORDERED;
 	wq->saved_max_active = max_active;
-	if (wq->flags & WQ_UNBOUND)
-		wq->saved_min_active = min(wq->saved_min_active, max_active);
-
 	wq_adjust_max_active(wq);
 
 	mutex_unlock(&wq->mutex);
@@ -6064,10 +5799,6 @@ int workqueue_online_cpu(unsigned int cp
 
 			for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
 				wq_update_pod(wq, tcpu, cpu, true);
-
-			mutex_lock(&wq->mutex);
-			wq_update_node_max_active(wq, -1);
-			mutex_unlock(&wq->mutex);
 		}
 	}
 
@@ -6096,10 +5827,6 @@ int workqueue_offline_cpu(unsigned int c
 
 			for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
 				wq_update_pod(wq, tcpu, cpu, false);
-
-			mutex_lock(&wq->mutex);
-			wq_update_node_max_active(wq, cpu);
-			mutex_unlock(&wq->mutex);
 		}
 	}
 	mutex_unlock(&wq_pool_mutex);
@@ -7296,12 +7023,8 @@ void __init workqueue_init_topology(void
 	 * combinations to apply per-pod sharing.
 	 */
 	list_for_each_entry(wq, &workqueues, list) {
-		for_each_online_cpu(cpu)
+		for_each_online_cpu(cpu) {
 			wq_update_pod(wq, cpu, cpu, true);
-		if (wq->flags & WQ_UNBOUND) {
-			mutex_lock(&wq->mutex);
-			wq_update_node_max_active(wq, -1);
-			mutex_unlock(&wq->mutex);
 		}
 	}
 

[PATCH 6.6 04/11] Revert "workqueue: Introduce struct wq_node_nr_active"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit b522229a56941adac1ea1da6593b2b5c734b5359 which is
commit 91ccc6e7233bb10a9c176aa4cc70d6f432a441a5 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |  142 ++---------------------------------------------------
 1 file changed, 7 insertions(+), 135 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -281,16 +281,6 @@ struct wq_flusher {
 struct wq_device;
 
 /*
- * Unlike in a per-cpu workqueue where max_active limits its concurrency level
- * on each CPU, in an unbound workqueue, max_active applies to the whole system.
- * As sharing a single nr_active across multiple sockets can be very expensive,
- * the counting and enforcement is per NUMA node.
- */
-struct wq_node_nr_active {
-	atomic_t		nr;		/* per-node nr_active count */
-};
-
-/*
  * The externally visible workqueue.  It relays the issued work items to
  * the appropriate worker_pool through its pool_workqueues.
  */
@@ -336,7 +326,6 @@ struct workqueue_struct {
 	/* hot fields used during command issue, aligned to cacheline */
 	unsigned int		flags ____cacheline_aligned; /* WQ: WQ_* flags */
 	struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
-	struct wq_node_nr_active *node_nr_active[]; /* I: per-node nr_active */
 };
 
 static struct kmem_cache *pwq_cache;
@@ -1427,31 +1416,6 @@ work_func_t wq_worker_last_func(struct t
 }
 
 /**
- * wq_node_nr_active - Determine wq_node_nr_active to use
- * @wq: workqueue of interest
- * @node: NUMA node, can be %NUMA_NO_NODE
- *
- * Determine wq_node_nr_active to use for @wq on @node. Returns:
- *
- * - %NULL for per-cpu workqueues as they don't need to use shared nr_active.
- *
- * - node_nr_active[nr_node_ids] if @node is %NUMA_NO_NODE.
- *
- * - Otherwise, node_nr_active[@node].
- */
-static struct wq_node_nr_active *wq_node_nr_active(struct workqueue_struct *wq,
-						   int node)
-{
-	if (!(wq->flags & WQ_UNBOUND))
-		return NULL;
-
-	if (node == NUMA_NO_NODE)
-		node = nr_node_ids;
-
-	return wq->node_nr_active[node];
-}
-
-/**
  * get_pwq - get an extra reference on the specified pool_workqueue
  * @pwq: pool_workqueue to get
  *
@@ -1532,17 +1496,12 @@ static bool pwq_activate_work(struct poo
 			      struct work_struct *work)
 {
 	struct worker_pool *pool = pwq->pool;
-	struct wq_node_nr_active *nna;
 
 	lockdep_assert_held(&pool->lock);
 
 	if (!(*work_data_bits(work) & WORK_STRUCT_INACTIVE))
 		return false;
 
-	nna = wq_node_nr_active(pwq->wq, pool->node);
-	if (nna)
-		atomic_inc(&nna->nr);
-
 	pwq->nr_active++;
 	__pwq_activate_work(pwq, work);
 	return true;
@@ -1559,18 +1518,14 @@ static bool pwq_tryinc_nr_active(struct
 {
 	struct workqueue_struct *wq = pwq->wq;
 	struct worker_pool *pool = pwq->pool;
-	struct wq_node_nr_active *nna = wq_node_nr_active(wq, pool->node);
 	bool obtained;
 
 	lockdep_assert_held(&pool->lock);
 
 	obtained = pwq->nr_active < READ_ONCE(wq->max_active);
 
-	if (obtained) {
+	if (obtained)
 		pwq->nr_active++;
-		if (nna)
-			atomic_inc(&nna->nr);
-	}
 	return obtained;
 }
 
@@ -1607,26 +1562,10 @@ static bool pwq_activate_first_inactive(
 static void pwq_dec_nr_active(struct pool_workqueue *pwq)
 {
 	struct worker_pool *pool = pwq->pool;
-	struct wq_node_nr_active *nna = wq_node_nr_active(pwq->wq, pool->node);
 
 	lockdep_assert_held(&pool->lock);
 
-	/*
-	 * @pwq->nr_active should be decremented for both percpu and unbound
-	 * workqueues.
-	 */
 	pwq->nr_active--;
-
-	/*
-	 * For a percpu workqueue, it's simple. Just need to kick the first
-	 * inactive work item on @pwq itself.
-	 */
-	if (!nna) {
-		pwq_activate_first_inactive(pwq);
-		return;
-	}
-
-	atomic_dec(&nna->nr);
 	pwq_activate_first_inactive(pwq);
 }
 
@@ -4081,63 +4020,11 @@ static void wq_free_lockdep(struct workq
 }
 #endif
 
-static void free_node_nr_active(struct wq_node_nr_active **nna_ar)
-{
-	int node;
-
-	for_each_node(node) {
-		kfree(nna_ar[node]);
-		nna_ar[node] = NULL;
-	}
-
-	kfree(nna_ar[nr_node_ids]);
-	nna_ar[nr_node_ids] = NULL;
-}
-
-static void init_node_nr_active(struct wq_node_nr_active *nna)
-{
-	atomic_set(&nna->nr, 0);
-}
-
-/*
- * Each node's nr_active counter will be accessed mostly from its own node and
- * should be allocated in the node.
- */
-static int alloc_node_nr_active(struct wq_node_nr_active **nna_ar)
-{
-	struct wq_node_nr_active *nna;
-	int node;
-
-	for_each_node(node) {
-		nna = kzalloc_node(sizeof(*nna), GFP_KERNEL, node);
-		if (!nna)
-			goto err_free;
-		init_node_nr_active(nna);
-		nna_ar[node] = nna;
-	}
-
-	/* [nr_node_ids] is used as the fallback */
-	nna = kzalloc_node(sizeof(*nna), GFP_KERNEL, NUMA_NO_NODE);
-	if (!nna)
-		goto err_free;
-	init_node_nr_active(nna);
-	nna_ar[nr_node_ids] = nna;
-
-	return 0;
-
-err_free:
-	free_node_nr_active(nna_ar);
-	return -ENOMEM;
-}
-
 static void rcu_free_wq(struct rcu_head *rcu)
 {
 	struct workqueue_struct *wq =
 		container_of(rcu, struct workqueue_struct, rcu);
 
-	if (wq->flags & WQ_UNBOUND)
-		free_node_nr_active(wq->node_nr_active);
-
 	wq_free_lockdep(wq);
 	free_percpu(wq->cpu_pwq);
 	free_workqueue_attrs(wq->unbound_attrs);
@@ -4889,8 +4776,7 @@ struct workqueue_struct *alloc_workqueue
 {
 	va_list args;
 	struct workqueue_struct *wq;
-	size_t wq_size;
-	int name_len;
+	int len;
 
 	/*
 	 * Unbound && max_active == 1 used to imply ordered, which is no longer
@@ -4906,12 +4792,7 @@ struct workqueue_struct *alloc_workqueue
 		flags |= WQ_UNBOUND;
 
 	/* allocate wq and format name */
-	if (flags & WQ_UNBOUND)
-		wq_size = struct_size(wq, node_nr_active, nr_node_ids + 1);
-	else
-		wq_size = sizeof(*wq);
-
-	wq = kzalloc(wq_size, GFP_KERNEL);
+	wq = kzalloc(sizeof(*wq), GFP_KERNEL);
 	if (!wq)
 		return NULL;
 
@@ -4922,12 +4803,11 @@ struct workqueue_struct *alloc_workqueue
 	}
 
 	va_start(args, max_active);
-	name_len = vsnprintf(wq->name, sizeof(wq->name), fmt, args);
+	len = vsnprintf(wq->name, sizeof(wq->name), fmt, args);
 	va_end(args);
 
-	if (name_len >= WQ_NAME_LEN)
-		pr_warn_once("workqueue: name exceeds WQ_NAME_LEN. Truncating to: %s\n",
-			     wq->name);
+	if (len >= WQ_NAME_LEN)
+		pr_warn_once("workqueue: name exceeds WQ_NAME_LEN. Truncating to: %s\n", wq->name);
 
 	max_active = max_active ?: WQ_DFL_ACTIVE;
 	max_active = wq_clamp_max_active(max_active, flags, wq->name);
@@ -4946,13 +4826,8 @@ struct workqueue_struct *alloc_workqueue
 	wq_init_lockdep(wq);
 	INIT_LIST_HEAD(&wq->list);
 
-	if (flags & WQ_UNBOUND) {
-		if (alloc_node_nr_active(wq->node_nr_active) < 0)
-			goto err_unreg_lockdep;
-	}
-
 	if (alloc_and_link_pwqs(wq) < 0)
-		goto err_free_node_nr_active;
+		goto err_unreg_lockdep;
 
 	if (wq_online && init_rescuer(wq) < 0)
 		goto err_destroy;
@@ -4977,9 +4852,6 @@ struct workqueue_struct *alloc_workqueue
 
 	return wq;
 
-err_free_node_nr_active:
-	if (wq->flags & WQ_UNBOUND)
-		free_node_nr_active(wq->node_nr_active);
 err_unreg_lockdep:
 	wq_unregister_lockdep(wq);
 	wq_free_lockdep(wq);

[PATCH 6.6 05/11] Revert "workqueue: RCU protect wq->dfl_pwq and implement accessors for it"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit bd31fb926dfa02d2ccfb4b79389168b1d16f36b1 which is
commit 9f66cff212bb3c1cd25996aaa0dfd0c9e9d8baab upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |   64 +++++++++++++++++++----------------------------------
 1 file changed, 24 insertions(+), 40 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -304,7 +304,7 @@ struct workqueue_struct {
 	int			saved_max_active; /* WQ: saved max_active */
 
 	struct workqueue_attrs	*unbound_attrs;	/* PW: only for unbound wqs */
-	struct pool_workqueue __rcu *dfl_pwq;   /* PW: only for unbound wqs */
+	struct pool_workqueue	*dfl_pwq;	/* PW: only for unbound wqs */
 
 #ifdef CONFIG_SYSFS
 	struct wq_device	*wq_dev;	/* I: for sysfs interface */
@@ -629,23 +629,6 @@ static int worker_pool_assign_id(struct
 	return ret;
 }
 
-static struct pool_workqueue __rcu **
-unbound_pwq_slot(struct workqueue_struct *wq, int cpu)
-{
-       if (cpu >= 0)
-               return per_cpu_ptr(wq->cpu_pwq, cpu);
-       else
-               return &wq->dfl_pwq;
-}
-
-/* @cpu < 0 for dfl_pwq */
-static struct pool_workqueue *unbound_pwq(struct workqueue_struct *wq, int cpu)
-{
-	return rcu_dereference_check(*unbound_pwq_slot(wq, cpu),
-				     lockdep_is_held(&wq_pool_mutex) ||
-				     lockdep_is_held(&wq->mutex));
-}
-
 static unsigned int work_color_to_flags(int color)
 {
 	return color << WORK_STRUCT_COLOR_SHIFT;
@@ -4335,11 +4318,10 @@ static void wq_calc_pod_cpumask(struct w
 				"possible intersect\n");
 }
 
-/* install @pwq into @wq and return the old pwq, @cpu < 0 for dfl_pwq */
+/* install @pwq into @wq's cpu_pwq and return the old pwq */
 static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq,
 					int cpu, struct pool_workqueue *pwq)
 {
-	struct pool_workqueue __rcu **slot = unbound_pwq_slot(wq, cpu);
 	struct pool_workqueue *old_pwq;
 
 	lockdep_assert_held(&wq_pool_mutex);
@@ -4348,8 +4330,8 @@ static struct pool_workqueue *install_un
 	/* link_pwq() can handle duplicate calls */
 	link_pwq(pwq);
 
-	old_pwq = rcu_access_pointer(*slot);
-	rcu_assign_pointer(*slot, pwq);
+	old_pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
+	rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq);
 	return old_pwq;
 }
 
@@ -4449,11 +4431,14 @@ static void apply_wqattrs_commit(struct
 
 	copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);
 
-	/* save the previous pwqs and install the new ones */
+	/* save the previous pwq and install the new one */
 	for_each_possible_cpu(cpu)
 		ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu,
 							ctx->pwq_tbl[cpu]);
-	ctx->dfl_pwq = install_unbound_pwq(ctx->wq, -1, ctx->dfl_pwq);
+
+	/* @dfl_pwq might not have been used, ensure it's linked */
+	link_pwq(ctx->dfl_pwq);
+	swap(ctx->wq->dfl_pwq, ctx->dfl_pwq);
 
 	mutex_unlock(&ctx->wq->mutex);
 }
@@ -4576,7 +4561,9 @@ static void wq_update_pod(struct workque
 
 	/* nothing to do if the target cpumask matches the current pwq */
 	wq_calc_pod_cpumask(target_attrs, cpu, off_cpu);
-	if (wqattrs_equal(target_attrs, unbound_pwq(wq, cpu)->pool->attrs))
+	pwq = rcu_dereference_protected(*per_cpu_ptr(wq->cpu_pwq, cpu),
+					lockdep_is_held(&wq_pool_mutex));
+	if (wqattrs_equal(target_attrs, pwq->pool->attrs))
 		return;
 
 	/* create a new pwq */
@@ -4594,11 +4581,10 @@ static void wq_update_pod(struct workque
 
 use_dfl_pwq:
 	mutex_lock(&wq->mutex);
-	pwq = unbound_pwq(wq, -1);
-	raw_spin_lock_irq(&pwq->pool->lock);
-	get_pwq(pwq);
-	raw_spin_unlock_irq(&pwq->pool->lock);
-	old_pwq = install_unbound_pwq(wq, cpu, pwq);
+	raw_spin_lock_irq(&wq->dfl_pwq->pool->lock);
+	get_pwq(wq->dfl_pwq);
+	raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock);
+	old_pwq = install_unbound_pwq(wq, cpu, wq->dfl_pwq);
 out_unlock:
 	mutex_unlock(&wq->mutex);
 	put_pwq_unlocked(old_pwq);
@@ -4636,13 +4622,10 @@ static int alloc_and_link_pwqs(struct wo
 
 	cpus_read_lock();
 	if (wq->flags & __WQ_ORDERED) {
-		struct pool_workqueue *dfl_pwq;
-
 		ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
 		/* there should only be single pwq for ordering guarantee */
-		dfl_pwq = rcu_access_pointer(wq->dfl_pwq);
-		WARN(!ret && (wq->pwqs.next != &dfl_pwq->pwqs_node ||
-			      wq->pwqs.prev != &dfl_pwq->pwqs_node),
+		WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node ||
+			      wq->pwqs.prev != &wq->dfl_pwq->pwqs_node),
 		     "ordering guarantee broken for workqueue %s\n", wq->name);
 	} else {
 		ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
@@ -4873,7 +4856,7 @@ static bool pwq_busy(struct pool_workque
 		if (pwq->nr_in_flight[i])
 			return true;
 
-	if ((pwq != rcu_access_pointer(pwq->wq->dfl_pwq)) && (pwq->refcnt > 1))
+	if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
 		return true;
 	if (!pwq_is_empty(pwq))
 		return true;
@@ -4957,12 +4940,13 @@ void destroy_workqueue(struct workqueue_
 	rcu_read_lock();
 
 	for_each_possible_cpu(cpu) {
-		put_pwq_unlocked(unbound_pwq(wq, cpu));
-		RCU_INIT_POINTER(*unbound_pwq_slot(wq, cpu), NULL);
+		pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
+		RCU_INIT_POINTER(*per_cpu_ptr(wq->cpu_pwq, cpu), NULL);
+		put_pwq_unlocked(pwq);
 	}
 
-	put_pwq_unlocked(unbound_pwq(wq, -1));
-	RCU_INIT_POINTER(*unbound_pwq_slot(wq, -1), NULL);
+	put_pwq_unlocked(wq->dfl_pwq);
+	wq->dfl_pwq = NULL;
 
 	rcu_read_unlock();
 }

[PATCH 6.6 06/11] Revert "workqueue: Make wq_adjust_max_active() round-robin pwqs while activating"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 5f99fee6f2dea1228980c3e785ab1a2c69b4da3c which is
commit qc5404d4e6df6faba1007544b5f4e62c7c14416dd upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |   33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4710,7 +4710,7 @@ static int init_rescuer(struct workqueue
  */
 static void wq_adjust_max_active(struct workqueue_struct *wq)
 {
-	bool activated;
+	struct pool_workqueue *pwq;
 
 	lockdep_assert_held(&wq->mutex);
 
@@ -4730,26 +4730,19 @@ static void wq_adjust_max_active(struct
 	 */
 	WRITE_ONCE(wq->max_active, wq->saved_max_active);
 
-	/*
-	 * Round-robin through pwq's activating the first inactive work item
-	 * until max_active is filled.
-	 */
-	do {
-		struct pool_workqueue *pwq;
+	for_each_pwq(pwq, wq) {
+		unsigned long flags;
+
+		/* this function can be called during early boot w/ irq disabled */
+		raw_spin_lock_irqsave(&pwq->pool->lock, flags);
 
-		activated = false;
-		for_each_pwq(pwq, wq) {
-			unsigned long flags;
-
-			/* can be called during early boot w/ irq disabled */
-			raw_spin_lock_irqsave(&pwq->pool->lock, flags);
-			if (pwq_activate_first_inactive(pwq)) {
-				activated = true;
-				kick_pool(pwq->pool);
-			}
-			raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
-		}
-	} while (activated);
+		while (pwq_activate_first_inactive(pwq))
+			;
+
+		kick_pool(pwq->pool);
+
+		raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
+	}
 }
 
 __printf(1, 4)

[PATCH 6.6 07/11] Revert "workqueue: Move nr_active handling into helpers"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 4023a2d95076918abe2757d60810642a8115b586 which is
commit 1c270b79ce0b8290f146255ea9057243f6dd3c17 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |   86 +++++++++++------------------------------------------
 1 file changed, 19 insertions(+), 67 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1458,14 +1458,11 @@ static bool pwq_is_empty(struct pool_wor
 static void __pwq_activate_work(struct pool_workqueue *pwq,
 				struct work_struct *work)
 {
-	unsigned long *wdb = work_data_bits(work);
-
-	WARN_ON_ONCE(!(*wdb & WORK_STRUCT_INACTIVE));
 	trace_workqueue_activate_work(work);
 	if (list_empty(&pwq->pool->worklist))
 		pwq->pool->watchdog_ts = jiffies;
 	move_linked_works(work, &pwq->pool->worklist, NULL);
-	__clear_bit(WORK_STRUCT_INACTIVE_BIT, wdb);
+	__clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
 }
 
 /**
@@ -1490,66 +1487,12 @@ static bool pwq_activate_work(struct poo
 	return true;
 }
 
-/**
- * pwq_tryinc_nr_active - Try to increment nr_active for a pwq
- * @pwq: pool_workqueue of interest
- *
- * Try to increment nr_active for @pwq. Returns %true if an nr_active count is
- * successfully obtained. %false otherwise.
- */
-static bool pwq_tryinc_nr_active(struct pool_workqueue *pwq)
-{
-	struct workqueue_struct *wq = pwq->wq;
-	struct worker_pool *pool = pwq->pool;
-	bool obtained;
-
-	lockdep_assert_held(&pool->lock);
-
-	obtained = pwq->nr_active < READ_ONCE(wq->max_active);
-
-	if (obtained)
-		pwq->nr_active++;
-	return obtained;
-}
-
-/**
- * pwq_activate_first_inactive - Activate the first inactive work item on a pwq
- * @pwq: pool_workqueue of interest
- *
- * Activate the first inactive work item of @pwq if available and allowed by
- * max_active limit.
- *
- * Returns %true if an inactive work item has been activated. %false if no
- * inactive work item is found or max_active limit is reached.
- */
-static bool pwq_activate_first_inactive(struct pool_workqueue *pwq)
-{
-	struct work_struct *work =
-		list_first_entry_or_null(&pwq->inactive_works,
-					 struct work_struct, entry);
-
-	if (work && pwq_tryinc_nr_active(pwq)) {
-		__pwq_activate_work(pwq, work);
-		return true;
-	} else {
-		return false;
-	}
-}
-
-/**
- * pwq_dec_nr_active - Retire an active count
- * @pwq: pool_workqueue of interest
- *
- * Decrement @pwq's nr_active and try to activate the first inactive work item.
- */
-static void pwq_dec_nr_active(struct pool_workqueue *pwq)
+static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
 {
-	struct worker_pool *pool = pwq->pool;
+	struct work_struct *work = list_first_entry(&pwq->inactive_works,
+						    struct work_struct, entry);
 
-	lockdep_assert_held(&pool->lock);
-
-	pwq->nr_active--;
-	pwq_activate_first_inactive(pwq);
+	pwq_activate_work(pwq, work);
 }
 
 /**
@@ -1567,8 +1510,14 @@ static void pwq_dec_nr_in_flight(struct
 {
 	int color = get_work_color(work_data);
 
-	if (!(work_data & WORK_STRUCT_INACTIVE))
-		pwq_dec_nr_active(pwq);
+	if (!(work_data & WORK_STRUCT_INACTIVE)) {
+		pwq->nr_active--;
+		if (!list_empty(&pwq->inactive_works)) {
+			/* one down, submit an inactive one */
+			if (pwq->nr_active < READ_ONCE(pwq->wq->max_active))
+				pwq_activate_first_inactive(pwq);
+		}
+	}
 
 	pwq->nr_in_flight[color]--;
 
@@ -1870,11 +1819,13 @@ retry:
 	 * @work must also queue behind existing inactive work items to maintain
 	 * ordering when max_active changes. See wq_adjust_max_active().
 	 */
-	if (list_empty(&pwq->inactive_works) && pwq_tryinc_nr_active(pwq)) {
+	if (list_empty(&pwq->inactive_works) &&
+	    pwq->nr_active < READ_ONCE(pwq->wq->max_active)) {
 		if (list_empty(&pool->worklist))
 			pool->watchdog_ts = jiffies;
 
 		trace_workqueue_activate_work(work);
+		pwq->nr_active++;
 		insert_work(pwq, work, &pool->worklist, work_flags);
 		kick_pool(pool);
 	} else {
@@ -4736,8 +4687,9 @@ static void wq_adjust_max_active(struct
 		/* this function can be called during early boot w/ irq disabled */
 		raw_spin_lock_irqsave(&pwq->pool->lock, flags);
 
-		while (pwq_activate_first_inactive(pwq))
-			;
+		while (!list_empty(&pwq->inactive_works) &&
+		       pwq->nr_active < wq->max_active)
+			pwq_activate_first_inactive(pwq);
 
 		kick_pool(pwq->pool);
 

[PATCH 6.6 08/11] Revert "workqueue: Replace pwq_activate_inactive_work() with [__]pwq_activate_work()"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 6c592f0bb96815117538491e5ba12e0a8a8c4493 which is
commit 4c6380305d21e36581b451f7337a36c93b64e050 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |   31 ++++++-------------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1455,36 +1455,16 @@ static bool pwq_is_empty(struct pool_wor
 	return !pwq->nr_active && list_empty(&pwq->inactive_works);
 }
 
-static void __pwq_activate_work(struct pool_workqueue *pwq,
-				struct work_struct *work)
+static void pwq_activate_inactive_work(struct work_struct *work)
 {
+	struct pool_workqueue *pwq = get_work_pwq(work);
+
 	trace_workqueue_activate_work(work);
 	if (list_empty(&pwq->pool->worklist))
 		pwq->pool->watchdog_ts = jiffies;
 	move_linked_works(work, &pwq->pool->worklist, NULL);
 	__clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
-}
-
-/**
- * pwq_activate_work - Activate a work item if inactive
- * @pwq: pool_workqueue @work belongs to
- * @work: work item to activate
- *
- * Returns %true if activated. %false if already active.
- */
-static bool pwq_activate_work(struct pool_workqueue *pwq,
-			      struct work_struct *work)
-{
-	struct worker_pool *pool = pwq->pool;
-
-	lockdep_assert_held(&pool->lock);
-
-	if (!(*work_data_bits(work) & WORK_STRUCT_INACTIVE))
-		return false;
-
 	pwq->nr_active++;
-	__pwq_activate_work(pwq, work);
-	return true;
 }
 
 static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
@@ -1492,7 +1472,7 @@ static void pwq_activate_first_inactive(
 	struct work_struct *work = list_first_entry(&pwq->inactive_works,
 						    struct work_struct, entry);
 
-	pwq_activate_work(pwq, work);
+	pwq_activate_inactive_work(work);
 }
 
 /**
@@ -1630,7 +1610,8 @@ static int try_to_grab_pending(struct wo
 		 * management later on and cause stall.  Make sure the work
 		 * item is activated before grabbing.
 		 */
-		pwq_activate_work(pwq, work);
+		if (*work_data_bits(work) & WORK_STRUCT_INACTIVE)
+			pwq_activate_inactive_work(work);
 
 		list_del_init(&work->entry);
 		pwq_dec_nr_in_flight(pwq, *work_data_bits(work));

[PATCH 6.6 09/11] Revert "workqueue: Factor out pwq_is_empty()"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit bad184d26a4f68aa00ad75502f9669950a790f71 which is
commit afa87ce85379e2d93863fce595afdb5771a84004 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |   13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1450,11 +1450,6 @@ static void put_pwq_unlocked(struct pool
 	}
 }
 
-static bool pwq_is_empty(struct pool_workqueue *pwq)
-{
-	return !pwq->nr_active && list_empty(&pwq->inactive_works);
-}
-
 static void pwq_activate_inactive_work(struct work_struct *work)
 {
 	struct pool_workqueue *pwq = get_work_pwq(work);
@@ -3324,7 +3319,7 @@ reflush:
 		bool drained;
 
 		raw_spin_lock_irq(&pwq->pool->lock);
-		drained = pwq_is_empty(pwq);
+		drained = !pwq->nr_active && list_empty(&pwq->inactive_works);
 		raw_spin_unlock_irq(&pwq->pool->lock);
 
 		if (drained)
@@ -4784,7 +4779,7 @@ static bool pwq_busy(struct pool_workque
 
 	if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
 		return true;
-	if (!pwq_is_empty(pwq))
+	if (pwq->nr_active || !list_empty(&pwq->inactive_works))
 		return true;
 
 	return false;
@@ -5222,7 +5217,7 @@ void show_one_workqueue(struct workqueue
 	unsigned long flags;
 
 	for_each_pwq(pwq, wq) {
-		if (!pwq_is_empty(pwq)) {
+		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
 			idle = false;
 			break;
 		}
@@ -5234,7 +5229,7 @@ void show_one_workqueue(struct workqueue
 
 	for_each_pwq(pwq, wq) {
 		raw_spin_lock_irqsave(&pwq->pool->lock, flags);
-		if (!pwq_is_empty(pwq)) {
+		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
 			/*
 			 * Defer printing to avoid deadlocks in console
 			 * drivers that queue work while holding locks

[PATCH 6.6 10/11] Revert "workqueue: Move pwq->max_active to wq->max_active"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 82e098f5bed1ff167332d26f8551662098747ec4 which is
commit a045a272d887575da17ad86d6573e82871b50c27 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |  133 ++++++++++++++++++++++++++---------------------------
 1 file changed, 67 insertions(+), 66 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -143,9 +143,6 @@ enum {
  *
  * WR: wq->mutex protected for writes.  RCU protected for reads.
  *
- * WO: wq->mutex protected for writes. Updated with WRITE_ONCE() and can be read
- *     with READ_ONCE() without locking.
- *
  * MD: wq_mayday_lock protected.
  *
  * WD: Used internally by the watchdog.
@@ -253,6 +250,7 @@ struct pool_workqueue {
 	 * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
 	 */
 	int			nr_active;	/* L: nr of active works */
+	int			max_active;	/* L: max active works */
 	struct list_head	inactive_works;	/* L: inactive works */
 	struct list_head	pwqs_node;	/* WR: node on wq->pwqs */
 	struct list_head	mayday_node;	/* MD: node on wq->maydays */
@@ -300,8 +298,7 @@ struct workqueue_struct {
 	struct worker		*rescuer;	/* MD: rescue worker */
 
 	int			nr_drainers;	/* WQ: drain in progress */
-	int			max_active;	/* WO: max active works */
-	int			saved_max_active; /* WQ: saved max_active */
+	int			saved_max_active; /* WQ: saved pwq max_active */
 
 	struct workqueue_attrs	*unbound_attrs;	/* PW: only for unbound wqs */
 	struct pool_workqueue	*dfl_pwq;	/* PW: only for unbound wqs */
@@ -1489,7 +1486,7 @@ static void pwq_dec_nr_in_flight(struct
 		pwq->nr_active--;
 		if (!list_empty(&pwq->inactive_works)) {
 			/* one down, submit an inactive one */
-			if (pwq->nr_active < READ_ONCE(pwq->wq->max_active))
+			if (pwq->nr_active < pwq->max_active)
 				pwq_activate_first_inactive(pwq);
 		}
 	}
@@ -1790,13 +1787,7 @@ retry:
 	pwq->nr_in_flight[pwq->work_color]++;
 	work_flags = work_color_to_flags(pwq->work_color);
 
-	/*
-	 * Limit the number of concurrently active work items to max_active.
-	 * @work must also queue behind existing inactive work items to maintain
-	 * ordering when max_active changes. See wq_adjust_max_active().
-	 */
-	if (list_empty(&pwq->inactive_works) &&
-	    pwq->nr_active < READ_ONCE(pwq->wq->max_active)) {
+	if (likely(pwq->nr_active < pwq->max_active)) {
 		if (list_empty(&pool->worklist))
 			pool->watchdog_ts = jiffies;
 
@@ -4145,6 +4136,50 @@ static void pwq_release_workfn(struct kt
 	}
 }
 
+/**
+ * pwq_adjust_max_active - update a pwq's max_active to the current setting
+ * @pwq: target pool_workqueue
+ *
+ * If @pwq isn't freezing, set @pwq->max_active to the associated
+ * workqueue's saved_max_active and activate inactive work items
+ * accordingly.  If @pwq is freezing, clear @pwq->max_active to zero.
+ */
+static void pwq_adjust_max_active(struct pool_workqueue *pwq)
+{
+	struct workqueue_struct *wq = pwq->wq;
+	bool freezable = wq->flags & WQ_FREEZABLE;
+	unsigned long flags;
+
+	/* for @wq->saved_max_active */
+	lockdep_assert_held(&wq->mutex);
+
+	/* fast exit for non-freezable wqs */
+	if (!freezable && pwq->max_active == wq->saved_max_active)
+		return;
+
+	/* this function can be called during early boot w/ irq disabled */
+	raw_spin_lock_irqsave(&pwq->pool->lock, flags);
+
+	/*
+	 * During [un]freezing, the caller is responsible for ensuring that
+	 * this function is called at least once after @workqueue_freezing
+	 * is updated and visible.
+	 */
+	if (!freezable || !workqueue_freezing) {
+		pwq->max_active = wq->saved_max_active;
+
+		while (!list_empty(&pwq->inactive_works) &&
+		       pwq->nr_active < pwq->max_active)
+			pwq_activate_first_inactive(pwq);
+
+		kick_pool(pwq->pool);
+	} else {
+		pwq->max_active = 0;
+	}
+
+	raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
+}
+
 /* initialize newly allocated @pwq which is associated with @wq and @pool */
 static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
 		     struct worker_pool *pool)
@@ -4177,6 +4212,9 @@ static void link_pwq(struct pool_workque
 	/* set the matching work_color */
 	pwq->work_color = wq->work_color;
 
+	/* sync max_active to the current setting */
+	pwq_adjust_max_active(pwq);
+
 	/* link in @pwq */
 	list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
 }
@@ -4627,52 +4665,6 @@ static int init_rescuer(struct workqueue
 	return 0;
 }
 
-/**
- * wq_adjust_max_active - update a wq's max_active to the current setting
- * @wq: target workqueue
- *
- * If @wq isn't freezing, set @wq->max_active to the saved_max_active and
- * activate inactive work items accordingly. If @wq is freezing, clear
- * @wq->max_active to zero.
- */
-static void wq_adjust_max_active(struct workqueue_struct *wq)
-{
-	struct pool_workqueue *pwq;
-
-	lockdep_assert_held(&wq->mutex);
-
-	if ((wq->flags & WQ_FREEZABLE) && workqueue_freezing) {
-		WRITE_ONCE(wq->max_active, 0);
-		return;
-	}
-
-	if (wq->max_active == wq->saved_max_active)
-		return;
-
-	/*
-	 * Update @wq->max_active and then kick inactive work items if more
-	 * active work items are allowed. This doesn't break work item ordering
-	 * because new work items are always queued behind existing inactive
-	 * work items if there are any.
-	 */
-	WRITE_ONCE(wq->max_active, wq->saved_max_active);
-
-	for_each_pwq(pwq, wq) {
-		unsigned long flags;
-
-		/* this function can be called during early boot w/ irq disabled */
-		raw_spin_lock_irqsave(&pwq->pool->lock, flags);
-
-		while (!list_empty(&pwq->inactive_works) &&
-		       pwq->nr_active < wq->max_active)
-			pwq_activate_first_inactive(pwq);
-
-		kick_pool(pwq->pool);
-
-		raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
-	}
-}
-
 __printf(1, 4)
 struct workqueue_struct *alloc_workqueue(const char *fmt,
 					 unsigned int flags,
@@ -4680,6 +4672,7 @@ struct workqueue_struct *alloc_workqueue
 {
 	va_list args;
 	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
 	int len;
 
 	/*
@@ -4718,7 +4711,6 @@ struct workqueue_struct *alloc_workqueue
 
 	/* init wq */
 	wq->flags = flags;
-	wq->max_active = max_active;
 	wq->saved_max_active = max_active;
 	mutex_init(&wq->mutex);
 	atomic_set(&wq->nr_pwqs_to_flush, 0);
@@ -4747,7 +4739,8 @@ struct workqueue_struct *alloc_workqueue
 	mutex_lock(&wq_pool_mutex);
 
 	mutex_lock(&wq->mutex);
-	wq_adjust_max_active(wq);
+	for_each_pwq(pwq, wq)
+		pwq_adjust_max_active(pwq);
 	mutex_unlock(&wq->mutex);
 
 	list_add_tail_rcu(&wq->list, &workqueues);
@@ -4885,6 +4878,8 @@ EXPORT_SYMBOL_GPL(destroy_workqueue);
  */
 void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 {
+	struct pool_workqueue *pwq;
+
 	/* disallow meddling with max_active for ordered workqueues */
 	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
 		return;
@@ -4895,7 +4890,9 @@ void workqueue_set_max_active(struct wor
 
 	wq->flags &= ~__WQ_ORDERED;
 	wq->saved_max_active = max_active;
-	wq_adjust_max_active(wq);
+
+	for_each_pwq(pwq, wq)
+		pwq_adjust_max_active(pwq);
 
 	mutex_unlock(&wq->mutex);
 }
@@ -5142,8 +5139,8 @@ static void show_pwq(struct pool_workque
 	pr_info("  pwq %d:", pool->id);
 	pr_cont_pool_info(pool);
 
-	pr_cont(" active=%d refcnt=%d%s\n",
-		pwq->nr_active, pwq->refcnt,
+	pr_cont(" active=%d/%d refcnt=%d%s\n",
+		pwq->nr_active, pwq->max_active, pwq->refcnt,
 		!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");
 
 	hash_for_each(pool->busy_hash, bkt, worker, hentry) {
@@ -5691,6 +5688,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu_safe_key);
 void freeze_workqueues_begin(void)
 {
 	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
 
 	mutex_lock(&wq_pool_mutex);
 
@@ -5699,7 +5697,8 @@ void freeze_workqueues_begin(void)
 
 	list_for_each_entry(wq, &workqueues, list) {
 		mutex_lock(&wq->mutex);
-		wq_adjust_max_active(wq);
+		for_each_pwq(pwq, wq)
+			pwq_adjust_max_active(pwq);
 		mutex_unlock(&wq->mutex);
 	}
 
@@ -5764,6 +5763,7 @@ out_unlock:
 void thaw_workqueues(void)
 {
 	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
 
 	mutex_lock(&wq_pool_mutex);
 
@@ -5775,7 +5775,8 @@ void thaw_workqueues(void)
 	/* restore max_active and repopulate worklist */
 	list_for_each_entry(wq, &workqueues, list) {
 		mutex_lock(&wq->mutex);
-		wq_adjust_max_active(wq);
+		for_each_pwq(pwq, wq)
+			pwq_adjust_max_active(pwq);
 		mutex_unlock(&wq->mutex);
 	}
 

[PATCH 6.6 11/11] Revert "workqueue.c: Increase workqueue name length"

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 43a181f8f41aca27e7454cf44a6dfbccc8b14e92 which is
commit 31c89007285d365aa36f71d8fb0701581c770a27 upstream.

The workqueue patches backported to 6.6.y caused some reported
regressions, so revert them for now.

Reported-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Tejun Heo <tj@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Audra Mitchell <audra@redhat.com>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/workqueue.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -108,7 +108,7 @@ enum {
 	RESCUER_NICE_LEVEL	= MIN_NICE,
 	HIGHPRI_NICE_LEVEL	= MIN_NICE,
 
-	WQ_NAME_LEN		= 32,
+	WQ_NAME_LEN		= 24,
 };
 
 /*
@@ -4673,7 +4673,6 @@ struct workqueue_struct *alloc_workqueue
 	va_list args;
 	struct workqueue_struct *wq;
 	struct pool_workqueue *pwq;
-	int len;
 
 	/*
 	 * Unbound && max_active == 1 used to imply ordered, which is no longer
@@ -4700,12 +4699,9 @@ struct workqueue_struct *alloc_workqueue
 	}
 
 	va_start(args, max_active);
-	len = vsnprintf(wq->name, sizeof(wq->name), fmt, args);
+	vsnprintf(wq->name, sizeof(wq->name), fmt, args);
 	va_end(args);
 
-	if (len >= WQ_NAME_LEN)
-		pr_warn_once("workqueue: name exceeds WQ_NAME_LEN. Truncating to: %s\n", wq->name);
-
 	max_active = max_active ?: WQ_DFL_ACTIVE;
 	max_active = wq_clamp_max_active(max_active, flags, wq->name);
 

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Shuah Khan]

On 4/3/24 11:55, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h
> 

Compiled and booted on my test system. No dmesg regressions.

Tested-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Ron Economos]

On 4/3/24 10:55 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h

Built and booted successfully on RISC-V RV64 (HiFive Unmatched).

Tested-by: Ron Economos <re@w6rz.net>

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Jon Hunter]

On Wed, 03 Apr 2024 19:55:49 +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

All tests passing for Tegra ...

Test results for stable-v6.6:
    10 builds:	10 pass, 0 fail
    26 boots:	26 pass, 0 fail
    116 tests:	116 pass, 0 fail

Linux version:	6.6.25-rc1-ge253a5c1b7de
Boards tested:	tegra124-jetson-tk1, tegra186-p2771-0000,
                tegra194-p2972-0000, tegra194-p3509-0000+p3668-0000,
                tegra20-ventana, tegra210-p2371-2180,
                tegra210-p3450-0000, tegra30-cardhu-a04

Tested-by: Jon Hunter <jonathanh@nvidia.com>

Jon

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Takeshi Ogasawara]

Hi Greg

On Thu, Apr 4, 2024 at 2:58 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
>         https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
> or in the git tree and branch at:
>         git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
>

6.6.25-rc1 tested.

Build successfully completed.
Boot successfully completed.
No dmesg regressions.
Video output normal.
Sound output normal.

Lenovo ThinkPad X1 Carbon Gen10(Intel i7-1260P(x86_64) arch linux)

[    0.000000] Linux version 6.6.25-rc1rv
(takeshi@ThinkPadX1Gen10J0764) (gcc (GCC) 13.2.1 20230801, GNU ld (GNU
Binutils) 2.42.0) #1 SMP PREEMPT_DYNAMIC Thu Apr  4 18:22:42 JST 2024

Thanks

Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com>

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 344 bytes --]

On Wed, Apr 03, 2024 at 07:55:49PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.

Tested-by: Mark Brown <broonie@kernel.org>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Naresh Kamboju]

On Wed, 3 Apr 2024 at 23:26, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
>         https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
> or in the git tree and branch at:
>         git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h


Results from Linaro’s test farm.
No regressions on arm64, arm, x86_64, and i386.

Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>

## Build
* kernel: 6.6.25-rc1
* git: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc
* git branch: linux-6.6.y
* git commit: e253a5c1b7de55d37ff656141e7001bdfd035d8c
* git describe: v6.6.24-12-ge253a5c1b7de
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-6.6.y/build/v6.6.24-12-ge253a5c1b7de

## Test Regressions (compared to v6.6.21)

## Metric Regressions (compared to v6.6.21)

## Test Fixes (compared to v6.6.21)

## Metric Fixes (compared to v6.6.21)

## Test result summary
total: 121780, pass: 106264, fail: 997, skip: 14420, xfail: 99

## Build Summary
* arc: 5 total, 5 passed, 0 failed
* arm: 131 total, 131 passed, 0 failed
* arm64: 40 total, 39 passed, 1 failed
* i386: 31 total, 31 passed, 0 failed
* mips: 24 total, 24 passed, 0 failed
* parisc: 3 total, 3 passed, 0 failed
* powerpc: 34 total, 34 passed, 0 failed
* riscv: 16 total, 16 passed, 0 failed
* s390: 12 total, 12 passed, 0 failed
* sh: 10 total, 10 passed, 0 failed
* sparc: 6 total, 6 passed, 0 failed
* x86_64: 35 total, 35 passed, 0 failed

## Test suites summary
* boot
* kselftest-arm64
* kselftest-breakpoints
* kselftest-capabilities
* kselftest-clone3
* kselftest-core
* kselftest-cpu-hotplug
* kselftest-exec
* kselftest-fpu
* kselftest-ftrace
* kselftest-futex
* kselftest-gpio
* kselftest-intel_pstate
* kselftest-ipc
* kselftest-kcmp
* kselftest-membarrier
* kselftest-memfd
* kselftest-mincore
* kselftest-mqueue
* kselftest-net
* kselftest-net-mptcp
* kselftest-openat2
* kselftest-ptrace
* kselftest-rseq
* kselftest-rtc
* kselftest-seccomp
* kselftest-sigaltstack
* kselftest-size
* kselftest-tc-testing
* kselftest-timers
* kselftest-tmpfs
* kselftest-tpm2
* kselftest-user_events
* kselftest-vDSO
* kselftest-x86
* kunit
* libgpiod
* libhugetlbfs
* log-parser-boot
* log-parser-test
* ltp-cap_bounds
* ltp-commands
* ltp-containers
* ltp-controllers
* ltp-crypto
* ltp-cve
* ltp-fcntl-locktests
* ltp-filecaps
* ltp-fs
* ltp-fs_bind
* ltp-fs_perms_simple
* ltp-hugetlb
* ltp-io
* ltp-ipc
* ltp-math
* ltp-mm
* ltp-nptl
* ltp-pty
* ltp-sched
* ltp-securebits
* ltp-smoke
* ltp-smoketest
* ltp-syscalls
* ltp-tracing
* perf
* rcutorture

--
Linaro LKFT
https://lkft.linaro.org

Re: [PATCH 6.6 00/11] 6.6.25-rc1 review

[Florian Fainelli]

On 4/3/24 10:55, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 6.6.25 release.
> There are 11 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Fri, 05 Apr 2024 17:51:13 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.6.25-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.6.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

On ARCH_BRCMSTB using 32-bit and 64-bit ARM kernels, build tested on 
BMIPS_GENERIC:

Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
-- 
Florian