From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ra.se.axis.com (ra.se.axis.com [195.60.68.13]) by ozlabs.org (Postfix) with ESMTP id 26F412C0504 for ; Mon, 24 Jun 2013 16:48:03 +1000 (EST) Date: Mon, 24 Jun 2013 08:41:56 +0200 From: Jesper Nilsson To: "Srivatsa S. Bhat" Subject: Re: [PATCH 33/45] cris/smp: Use get/put_online_cpus_atomic() to prevent CPU offline Message-ID: <20130624064156.GR23735@axis.com> References: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> <20130623134536.19094.52797.stgit@srivatsabhat.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20130623134536.19094.52797.stgit@srivatsabhat.in.ibm.com> Cc: peterz@infradead.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, walken@google.com, mingo@kernel.org, linux-arch@vger.kernel.org, vincent.guittot@linaro.org, linux-cris-kernel@axis.com, xiaoguangrong@linux.vnet.ibm.com, wangyun@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, rusty@rustcorp.com.au, rostedt@goodmis.org, Jesper Nilsson , Mikael Starvik , namhyung@kernel.org, tglx@linutronix.de, laijs@cn.fujitsu.com, zhong@linux.vnet.ibm.com, netdev@vger.kernel.org, oleg@redhat.com, sbw@mit.edu, tj@kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, Jun 23, 2013 at 07:15:39PM +0530, Srivatsa S. Bhat wrote: > Once stop_machine() is gone from the CPU offline path, we won't be able > to depend on disabling preemption to prevent CPUs from going offline > from under us. > > Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going > offline, while invoking from atomic context. > > Cc: Mikael Starvik Acked-by: Jesper Nilsson > Cc: Thomas Gleixner > Cc: linux-cris-kernel@axis.com > Signed-off-by: Srivatsa S. Bhat > --- > > arch/cris/arch-v32/kernel/smp.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/cris/arch-v32/kernel/smp.c b/arch/cris/arch-v32/kernel/smp.c > index cdd1202..b2d4612 100644 > --- a/arch/cris/arch-v32/kernel/smp.c > +++ b/arch/cris/arch-v32/kernel/smp.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -222,6 +223,7 @@ void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned > unsigned long flags; > cpumask_t cpu_mask; > > + get_online_cpus_atomic(); > spin_lock_irqsave(&tlbstate_lock, flags); > cpu_mask = (mm == FLUSH_ALL ? cpu_all_mask : *mm_cpumask(mm)); > cpumask_clear_cpu(smp_processor_id(), &cpu_mask); > @@ -230,6 +232,7 @@ void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned > flush_addr = addr; > send_ipi(IPI_FLUSH_TLB, 1, cpu_mask); > spin_unlock_irqrestore(&tlbstate_lock, flags); > + put_online_cpus_atomic(); > } > > void flush_tlb_all(void) > @@ -319,10 +322,12 @@ int smp_call_function(void (*func)(void *info), void *info, int wait) > data.info = info; > data.wait = wait; > > + get_online_cpus_atomic(); > spin_lock(&call_lock); > call_data = &data; > ret = send_ipi(IPI_CALL, wait, cpu_mask); > spin_unlock(&call_lock); > + put_online_cpus_atomic(); > > return ret; > } > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ /^JN - Jesper Nilsson -- Jesper Nilsson -- jesper.nilsson@axis.com