From: Heiko Carstens <hca@linux.ibm.com>
To: Pingfan Liu <kernelfans@gmail.com>
Cc: linux-s390@vger.kernel.org, Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/9] s390/irq: utilize RCU instead of irq_lock_sparse() in show_msi_interrupt()
Date: Thu, 21 Apr 2022 13:42:59 +0200 [thread overview]
Message-ID: <YmFDQ0wH+Y15bKX0@osiris> (raw)
In-Reply-To: <YmDRMUUzBq6uyIzj@piliu.users.ipa.redhat.com>
On Thu, Apr 21, 2022 at 11:36:17AM +0800, Pingfan Liu wrote:
> Oops. You are right. What about using rcu_read_lock() directly?
>
>
> diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
> index 3033f616e256..45393919fe61 100644
> --- a/arch/s390/kernel/irq.c
> +++ b/arch/s390/kernel/irq.c
> @@ -205,7 +205,7 @@ static void show_msi_interrupt(struct seq_file *p, int irq)
> unsigned long flags;
> int cpu;
>
> - irq_lock_sparse();
> + rcu_read_lock();
> desc = irq_to_desc(irq);
> if (!desc)
> goto out;
> @@ -224,7 +224,7 @@ static void show_msi_interrupt(struct seq_file *p, int irq)
> seq_putc(p, '\n');
> raw_spin_unlock_irqrestore(&desc->lock, flags);
> out:
> - irq_unlock_sparse();
> + rcu_read_unlock();
That looks like it should work. Please resend and also add a reference
to commit 74bdf7815dfb ("genirq: Speedup show_interrupts()") which
explains why this works.
next prev parent reply other threads:[~2022-04-21 11:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-20 14:05 [PATCH 0/9] trival fix or improvement about irq_desc access Pingfan Liu
2022-04-20 14:05 ` [PATCH 1/9] irq/irqdesc: put the lock at the exact place in irq_sysfs_init() Pingfan Liu
2022-04-20 14:05 ` [PATCH 2/9] irq/irqdesc: change the name of delete_irq_desc() to irq_delete_desc() Pingfan Liu
2022-04-20 14:05 ` [PATCH 3/9] irq/manage: remove some unreferenced code Pingfan Liu
2022-04-20 20:56 ` Miguel Ojeda
2022-04-20 14:05 ` [PATCH 4/9] s390/irq: utilize RCU instead of irq_lock_sparse() in show_msi_interrupt() Pingfan Liu
2022-04-20 18:16 ` Heiko Carstens
2022-04-21 3:36 ` Pingfan Liu
2022-04-21 11:42 ` Heiko Carstens [this message]
2022-04-22 9:56 ` Pingfan Liu
2022-04-22 10:02 ` [PATCHv2] " Pingfan Liu
2022-04-25 11:39 ` Heiko Carstens
2022-04-20 14:05 ` [PATCH 5/9] x86/irq: place for_each_active_irq() in rcu read section Pingfan Liu
2022-04-20 14:05 ` [PATCH 6/9] pm/irq: make for_each_irq_desc() safe of irq_desc release Pingfan Liu
2022-04-20 16:23 ` Rafael J. Wysocki
2022-04-21 3:31 ` Pingfan Liu
2022-04-21 10:57 ` Rafael J. Wysocki
2022-04-22 10:43 ` Pingfan Liu
2022-04-27 6:03 ` [PATCHv2] genirq/PM: Make " Pingfan Liu
2022-04-20 14:05 ` [PATCH 7/9] irq: remove needless lock in takedown_cpu() Pingfan Liu
2022-04-21 16:11 ` Thomas Gleixner
2022-04-25 2:57 ` Pingfan Liu
2022-04-25 9:43 ` Thomas Gleixner
2022-04-27 6:01 ` Pingfan Liu
2022-04-20 14:05 ` [PATCH 8/9] irq: make irq_lock_sparse() independent of CONFIG_SPARSE_IRQ Pingfan Liu
2022-04-20 14:05 ` [PATCH 9/9] irq/irqdesc: rename sparse_irq_lock to bitmap_lock Pingfan Liu
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