| Message ID | 20130623134536.19094.52797.stgit@srivatsabhat.in.ibm.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
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 <starvik@axis.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: linux-cris-kernel@axis.com > Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> > --- > > 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 <linux/init.h> > #include <linux/timex.h> > #include <linux/sched.h> > +#include <linux/cpu.h> > #include <linux/kernel.h> > #include <linux/cpumask.h> > #include <linux/interrupt.h> > @@ -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
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 <linux/init.h> #include <linux/timex.h> #include <linux/sched.h> +#include <linux/cpu.h> #include <linux/kernel.h> #include <linux/cpumask.h> #include <linux/interrupt.h> @@ -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; }
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 <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-cris-kernel@axis.com Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> --- arch/cris/arch-v32/kernel/smp.c | 5 +++++ 1 file changed, 5 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html