[ANNOUNCE] v5.14.1-rt21

From: Sebastian Andrzej Siewior
Date: Fri Sep 10 2021 - 15:10:56 EST

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Dear RT folks!

I'm pleased to announce the v5.14.1-rt21 patch set.

Changes since v5.14.1-rt20:

- The irq_work_sync() function sleep-waits instead of busy-poll on
PREEMPT_RT on work-items which are not invoked in hardirq context.

- Clark Williams reported issues in i915. Both have been addressed and
I hope for some feedback :)

- In v5.14-rt17 lockdep was taught to recognise read-locks. A last
minute change made the patch futile. A new version has been added.

- A patch to various drivers (acrn, smack, mt8195) to remove unused
variables which cause compile warning.

Known issues
- netconsole triggers WARN.

- The "Memory controller" (CONFIG_MEMCG) has been disabled.

- A RCU and ARM64 warning has been fixed by Valentin Schneider. It is
still not clear if the RCU related change is correct.

- Valentin Schneider reported a few splats on ARM64, see
https://https://lkml.kernel.org/r/.kernel.org/lkml/20210810134127.1394269-1-valentin.schneider@xxxxxxx/

The delta patch against v5.14.1-rt20 is appended below and can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.14/incr/patch-5.14.1-rt20-rt21.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.14.1-rt21

The RT patch against v5.14.1 can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.14/older/patch-5.14.1-rt21.patch.xz

The split quilt queue is available at:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.14/older/patches-5.14.1-rt21.tar.xz

Sebastian

diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index 38cc42783dfb2..594dec2f76954 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -318,10 +318,9 @@ void __intel_breadcrumbs_park(struct intel_breadcrumbs *b)
/* Kick the work once more to drain the signalers, and disarm the irq */
irq_work_sync(&b->irq_work);
while (READ_ONCE(b->irq_armed) && !atomic_read(&b->active)) {
- local_irq_disable();
- signal_irq_work(&b->irq_work);
- local_irq_enable();
+ irq_work_queue(&b->irq_work);
cond_resched();
+ irq_work_sync(&b->irq_work);
}
}

diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index fc77592d88a96..2ec1dd352960b 100644
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -1265,7 +1265,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* and context switches) submission.
*/

- spin_lock(&engine->active.lock);
+ spin_lock_irq(&engine->active.lock);

/*
* If the queue is higher priority than the last
@@ -1365,7 +1365,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* Even if ELSP[1] is occupied and not worthy
* of timeslices, our queue might be.
*/
- spin_unlock(&engine->active.lock);
+ spin_unlock_irq(&engine->active.lock);
return;
}
}
@@ -1391,7 +1391,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)

if (last && !can_merge_rq(last, rq)) {
spin_unlock(&ve->base.active.lock);
- spin_unlock(&engine->active.lock);
+ spin_unlock_irq(&engine->active.lock);
return; /* leave this for another sibling */
}

@@ -1552,7 +1552,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* interrupt for secondary ports).
*/
execlists->queue_priority_hint = queue_prio(execlists);
- spin_unlock(&engine->active.lock);
+ spin_unlock_irq(&engine->active.lock);

/*
* We can skip poking the HW if we ended up with exactly the same set
@@ -1578,13 +1578,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
}
}

-static void execlists_dequeue_irq(struct intel_engine_cs *engine)
-{
- local_irq_disable(); /* Suspend interrupts across request submission */
- execlists_dequeue(engine);
- local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */
-}
-
static void clear_ports(struct i915_request **ports, int count)
{
memset_p((void **)ports, NULL, count);
@@ -2377,7 +2370,7 @@ static void execlists_submission_tasklet(struct tasklet_struct *t)
}

if (!engine->execlists.pending[0]) {
- execlists_dequeue_irq(engine);
+ execlists_dequeue(engine);
start_timeslice(engine);
}

diff --git a/drivers/virt/acrn/irqfd.c b/drivers/virt/acrn/irqfd.c
index df5184979b282..d4ad211dce7a3 100644
--- a/drivers/virt/acrn/irqfd.c
+++ b/drivers/virt/acrn/irqfd.c
@@ -17,7 +17,6 @@
#include "acrn_drv.h"

static LIST_HEAD(acrn_irqfd_clients);
-static DEFINE_MUTEX(acrn_irqfds_mutex);

/**
* struct hsm_irqfd - Properties of HSM irqfd
diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index dbbef90897895..cfc3804ec9a09 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -3,6 +3,7 @@
#define _LINUX_IRQ_WORK_H

#include <linux/smp_types.h>
+#include <linux/rcuwait.h>

/*
* An entry can be in one of four states:
@@ -16,11 +17,13 @@
struct irq_work {
struct __call_single_node node;
void (*func)(struct irq_work *);
+ struct rcuwait irqwait;
};

#define __IRQ_WORK_INIT(_func, _flags) (struct irq_work){ \
.node = { .u_flags = (_flags), }, \
.func = (_func), \
+ .irqwait = __RCUWAIT_INITIALIZER(irqwait), \
}

#define IRQ_WORK_INIT(_func) __IRQ_WORK_INIT(_func, 0)
@@ -46,6 +49,11 @@ static inline bool irq_work_is_busy(struct irq_work *work)
return atomic_read(&work->node.a_flags) & IRQ_WORK_BUSY;
}

+static inline bool irq_work_is_hard(struct irq_work *work)
+{
+ return atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ;
+}
+
bool irq_work_queue(struct irq_work *work);
bool irq_work_queue_on(struct irq_work *work, int cpu);

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 0ec825dbe9f05..14c2aba4c9479 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -181,6 +181,10 @@ void irq_work_single(void *arg)
* else claimed it meanwhile.
*/
(void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY);
+
+ if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
+ !arch_irq_work_has_interrupt())
+ rcuwait_wake_up(&work->irqwait);
}

static void irq_work_run_list(struct llist_head *list)
@@ -247,6 +251,14 @@ void irq_work_tick_soft(void)
void irq_work_sync(struct irq_work *work)
{
lockdep_assert_irqs_enabled();
+ might_sleep();
+
+ if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
+ !arch_irq_work_has_interrupt()) {
+ rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
+ TASK_UNINTERRUPTIBLE);
+ return;
+ }

while (irq_work_is_busy(work))
cpu_relax();
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 6f22ad3617c9a..2997bfea10c7e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -5366,7 +5366,7 @@ int __lock_is_held(const struct lockdep_map *lock, int read)
struct held_lock *hlock = curr->held_locks + i;

if (match_held_lock(hlock, lock)) {
- if (read == -1 || hlock->read == !!read)
+ if (read == -1 || !!hlock->read == read)
return LOCK_STATE_HELD;

return LOCK_STATE_NOT_HELD;
diff --git a/localversion-rt b/localversion-rt
index e095ab8197147..6c6cde1c29e3d 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt20
+-rt21
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 223a6da0e6dc5..10793526187c0 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -51,8 +51,10 @@
#define SMK_RECEIVING 1
#define SMK_SENDING 2

+#ifdef SMACK_IPV6_PORT_LABELING
static DEFINE_MUTEX(smack_ipv6_lock);
static LIST_HEAD(smk_ipv6_port_list);
+#endif
struct kmem_cache *smack_rule_cache;
int smack_enabled;

@@ -2603,7 +2605,6 @@ static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
mutex_unlock(&smack_ipv6_lock);
return;
}
-#endif

/**
* smk_ipv6_port_check - check Smack port access
@@ -2666,6 +2667,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,

return smk_ipv6_check(skp, object, address, act);
}
+#endif

/**
* smack_inode_setsecurity - set smack xattrs
@@ -2852,8 +2854,9 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
SMK_CONNECTING);
}
- if (__is_defined(SMACK_IPV6_PORT_LABELING))
+#ifdef SMACK_IPV6_PORT_LABELING
rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
+#endif

return rc;
}
diff --git a/sound/soc/mediatek/common/mtk-afe-fe-dai.c b/sound/soc/mediatek/common/mtk-afe-fe-dai.c
index 3cb2adf420bbf..35c3174c035d7 100644
--- a/sound/soc/mediatek/common/mtk-afe-fe-dai.c
+++ b/sound/soc/mediatek/common/mtk-afe-fe-dai.c
@@ -288,7 +288,6 @@ const struct snd_soc_dai_ops mtk_afe_fe_ops = {
};
EXPORT_SYMBOL_GPL(mtk_afe_fe_ops);

-static DEFINE_MUTEX(irqs_lock);
int mtk_dynamic_irq_acquire(struct mtk_base_afe *afe)
{
int i;

Next message: Song Liu: "Re: [PATCH v6 bpf-next 1/3] perf: enable branch record for software events"
Previous message: Jens Axboe: "Re: [git pull] iov_iter fixes"
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