linux-kernel - [PATCH v4 06/11] smp: use smp_call_csd() from irq

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Message-Id: <20220519204943.1079578-7-dqiao@redhat.com>
Date:   Thu, 19 May 2022 16:49:38 -0400
From:   Donghai Qiao <dqiao@...hat.com>
To:     akpm@...ux-foundation.org, sfr@...b.auug.org.au, arnd@...db.de,
        peterz@...radead.org, heying24@...wei.com,
        andriy.shevchenko@...ux.intel.com, axboe@...nel.dk,
        rdunlap@...radead.org, tglx@...utronix.de, gor@...ux.ibm.com
Cc:     donghai.w.qiao@...il.com, linux-kernel@...r.kernel.org,
        Donghai Qiao <dqiao@...hat.com>
Subject: [PATCH v4 06/11] smp: use smp_call_csd() from irq_work.c and core.c

irq_work.c and core.c should use the cross interface rather than
using a unpublished internal function __smp_call_single_queue.

But this change also exposed unpublished types SMP_CALL_TYPE_TTWU and
SMP_CALL_TYPE_IRQ_WORK. However, this is a temporarily change so that
all kernel clients can call the interface as the first step. A
permanent solution should implement new cross call func() for both
and from there the TTWU and IRQ_WORK types of requests can be processed.
That way, the special TTWU and IRQ_WORK types will not be visible from
the cross call interface. Because this needs to change core.s and
irq_work.c, this should be done with a follow up patch set to reduce
the level of risk.

Signed-off-by: Donghai Qiao <dqiao@...hat.com>
---
v1 -> v2: Removed 'x' from the function names and change XCALL to
          SMP_CALL from the new macros
v2 -> v3: Modifed the commit comments

 kernel/irq_work.c   | 4 ++--
 kernel/sched/core.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc4..aa67ea2ccb8f 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -159,8 +159,8 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
 			if (!irq_work_claim(work))
 				goto out;
 		}
-
-		__smp_call_single_queue(cpu, &work->node.llist);
+		smp_call_csd(cpu, (call_single_data_t *)&work->node.llist,
+					SMP_CALL_TYPE_IRQ_WORK);
 	} else {
 		__irq_work_queue_local(work);
 	}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 51efaabac3e4..6d1d30bd6220 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3780,7 +3780,7 @@ static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags
 	p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
 
 	WRITE_ONCE(rq->ttwu_pending, 1);
-	__smp_call_single_queue(cpu, &p->wake_entry.llist);
+	smp_call_csd(cpu, (call_single_data_t *)&p->wake_entry.llist, SMP_CALL_TYPE_TTWU);
 }
 
 void wake_up_if_idle(int cpu)
-- 
2.27.0