On Sat, Sep 14, 2013 at 12:41:36PM +0800, Wang YanQing wrote: > On Thu, Sep 12, 2013 at 12:07:05AM +0800, Jiang Liu wrote: > > From: Jiang Liu <[email protected]> > > > > Commit f44310b98ddb7 "smp: Fix SMP function call empty cpu mask race" > > introduced field call_function_data->cpumask_ipi to resolve a race > > condition in smp_call_function_many(). > > > > Later commit 9a46ad6d6df3 "smp: make smp_call_function_many() use logic > > similar to smp_call_function_single()" fixed the same issue in another > > way when optimizing smp_call_function_many(), which then obsoletes > > changes introduced by commit f44310b98ddb7. So revert it. > > > > Signed-off-by: Jiang Liu <[email protected]> > > Acked-by: Wang YanQing <[email protected]> > > Cc: Jiang Liu <[email protected]> > > --- > > kernel/smp.c | 16 ++-------------- > > 1 file changed, 2 insertions(+), 14 deletions(-) > > > > diff --git a/kernel/smp.c b/kernel/smp.c > > index fe9f773..a034712 100644 > > --- a/kernel/smp.c > > +++ b/kernel/smp.c > > @@ -23,7 +23,6 @@ enum { > > struct call_function_data { > > struct call_single_data __percpu *csd; > > cpumask_var_t cpumask; > > - cpumask_var_t cpumask_ipi; > > }; > > > > static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data); > > @@ -47,9 +46,6 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long > > action, void *hcpu) > > if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, > > cpu_to_node(cpu))) > > return notifier_from_errno(-ENOMEM); > > - if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL, > > - cpu_to_node(cpu))) > > - return notifier_from_errno(-ENOMEM); > > cfd->csd = alloc_percpu(struct call_single_data); > > if (!cfd->csd) { > > free_cpumask_var(cfd->cpumask); > > @@ -64,7 +60,6 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long > > action, void *hcpu) > > case CPU_DEAD: > > case CPU_DEAD_FROZEN: > > free_cpumask_var(cfd->cpumask); > > - free_cpumask_var(cfd->cpumask_ipi); > > free_percpu(cfd->csd); > > break; > > #endif > > @@ -255,9 +250,9 @@ int smp_call_function_single(int cpu, smp_call_func_t > > func, void *info, > > csd = &__get_cpu_var(csd_data); > > > > csd_lock(csd); > > - > > csd->func = func; > > csd->info = info; > > + > > generic_exec_single(cpu, csd, wait); > > } else { > > err = -ENXIO; /* CPU not online */ > > @@ -410,13 +405,6 @@ void smp_call_function_many(const struct cpumask *mask, > > if (unlikely(!cpumask_weight(cfd->cpumask))) > > return; > > > > - /* > > - * After we put an entry into the list, cfd->cpumask may be cleared > > - * again when another CPU sends another IPI for a SMP function call, so > > - * cfd->cpumask will be zero. > > - */ > > - cpumask_copy(cfd->cpumask_ipi, cfd->cpumask); > > - > > for_each_cpu(cpu, cfd->cpumask) { > > struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu); > > struct call_single_queue *dst = > > @@ -433,7 +421,7 @@ void smp_call_function_many(const struct cpumask *mask, > > } > > > > /* Send a message to all CPUs in the map */ > > - arch_send_call_function_ipi_mask(cfd->cpumask_ipi); > > + arch_send_call_function_ipi_mask(cfd->cpumask); > > > > if (wait) { > > for_each_cpu(cpu, cfd->cpumask) { > > -- > > 1.8.1.2 > Hi Liu and all > > Commit 60c323699bb308404dcb60e8808531e02651578a > (kernel/smp.c: free related resources when failure occurs in hotplug_cfd()) > is a fix patch for commit you revert, and it had been merged into mainline. > > So could you ajust your patch to revert it together? I don't think we need > a separate patch to revert 60c323699bb308404dcb60e8808531e02651578a, because > your patch haven't be merged. > > Thanks.
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