linux-kernel - Re: [PATCH v2 03/14] arm: arm64: Don't use disable_nonboot

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Message-ID: <20200121165809.3kk3xauky4vjp5ni@e107158-lin.cambridge.arm.com>
Date:   Tue, 21 Jan 2020 16:58:09 +0000
From:   Qais Yousef <qais.yousef@....com>
To:     Russell King - ARM Linux admin <linux@...linux.org.uk>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 03/14] arm: arm64: Don't use disable_nonboot_cpus()

On 01/21/20 16:53, Russell King - ARM Linux admin wrote:
> On Tue, Jan 21, 2020 at 04:50:31PM +0000, Qais Yousef wrote:
> > On 11/25/19 11:27, Qais Yousef wrote:
> > > disable_nonboot_cpus() is not safe to use when doing machine_down(),
> > > because it relies on freeze_secondary_cpus() which in return is
> > > a suspend/resume related freeze and could abort if the logic detects any
> > > pending activities that can prevent finishing the offlining process.
> > > 
> > > Beside disable_nonboot_cpus() is dependent on CONFIG_PM_SLEEP_SMP which
> > > is an othogonal config to rely on to ensure this function works
> > > correctly.
> > > 
> > > Signed-off-by: Qais Yousef <qais.yousef@....com>
> > > CC: Russell King <linux@...linux.org.uk>
> > > CC: Catalin Marinas <catalin.marinas@....com>
> > > CC: Will Deacon <will@...nel.org>
> > > CC: linux-arm-kernel@...ts.infradead.org
> > > CC: linux-kernel@...r.kernel.org
> > > ---
> > 
> > Ping :)
> > 
> > I'm missing ACKs on this patch and patch 4 for arm64. Hopefully none should be
> > controversial.
> 
> ARM and ARM64 are maintained separately, so you can't submit a single
> patch covering both.  Sorry.

Sure I'd be happy to split.

It was just a single line change and I expected Thomas to pick the whole series
up, so I didn't think there'd be an issue in combining them up since they're
identical.

Do I take it you have no objection to the code change itself and just would
like to see this split up?

Thanks

--
Qais Yousef

> 
> > 
> > Thanks!
> > 
> > --
> > Qais Yousef
> > 
> > >  arch/arm/kernel/reboot.c    | 4 ++--
> > >  arch/arm64/kernel/process.c | 4 ++--
> > >  2 files changed, 4 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
> > > index bb18ed0539f4..58ad1a70f770 100644
> > > --- a/arch/arm/kernel/reboot.c
> > > +++ b/arch/arm/kernel/reboot.c
> > > @@ -88,11 +88,11 @@ void soft_restart(unsigned long addr)
> > >   * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
> > >   * kexec'd kernel to use any and all RAM as it sees fit, without having to
> > >   * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
> > > - * functionality embodied in disable_nonboot_cpus() to achieve this.
> > > + * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.
> > >   */
> > >  void machine_shutdown(void)
> > >  {
> > > -	disable_nonboot_cpus();
> > > +	smp_shutdown_nonboot_cpus(0);
> > >  }
> > >  
> > >  /*
> > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> > > index 71f788cd2b18..3bcc9bfc581e 100644
> > > --- a/arch/arm64/kernel/process.c
> > > +++ b/arch/arm64/kernel/process.c
> > > @@ -141,11 +141,11 @@ void arch_cpu_idle_dead(void)
> > >   * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
> > >   * kexec'd kernel to use any and all RAM as it sees fit, without having to
> > >   * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
> > > - * functionality embodied in disable_nonboot_cpus() to achieve this.
> > > + * functionality embodied in smpt_shutdown_nonboot_cpus() to achieve this.
> > >   */
> > >  void machine_shutdown(void)
> > >  {
> > > -	disable_nonboot_cpus();
> > > +	smp_shutdown_nonboot_cpus(0);
> > >  }
> > >  
> > >  /*
> > > -- 
> > > 2.17.1
> > > 
> > 
> 
> -- 
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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