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Commit b2bb8554 authored by Mike Travis's avatar Mike Travis
Browse files

x86: Remove cpumask games in x86/kernel/cpu/intel_cacheinfo.c 



Impact: remove cpumask_t from stack.

We should not try to save and restore cpus_allowed on current.

We can't use work_on_cpu() here, since it's in the hotplug cpu path
(if anyone else tries to get the hotplug lock from a workqueue we
could deadlock against them).

Fortunately, we can just use smp_call_function_single() since the
function can run from an interrupt.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarMike Travis <travis@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
parent 1de88cd4

arch/x86/kernel/cpu/intel_cacheinfo.c

+19 −22
Original line number Diff line number Diff line
@@ -534,31 +534,16 @@ static void __cpuinit free_cache_attributes(unsigned int cpu) 
	per_cpu(cpuid4_info, cpu) = NULL;

}



static int __cpuinit detect_cache_attributes(unsigned int cpu)

static void get_cpu_leaves(void *_retval)

{

	struct _cpuid4_info	*this_leaf;

	unsigned long		j;

	int			retval;

	cpumask_t		oldmask;



	if (num_cache_leaves == 0)

		return -ENOENT;



	per_cpu(cpuid4_info, cpu) = kzalloc(

	    sizeof(struct _cpuid4_info) * num_cache_leaves, GFP_KERNEL);

	if (per_cpu(cpuid4_info, cpu) == NULL)

		return -ENOMEM;



	oldmask = current->cpus_allowed;

	retval = set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

	if (retval)

		goto out;

	int j, *retval = _retval, cpu = smp_processor_id();



	/* Do cpuid and store the results */

	for (j = 0; j < num_cache_leaves; j++) {

		struct _cpuid4_info *this_leaf;

		this_leaf = CPUID4_INFO_IDX(cpu, j);

		retval = cpuid4_cache_lookup(j, this_leaf);

		if (unlikely(retval < 0)) {

		*retval = cpuid4_cache_lookup(j, this_leaf);

		if (unlikely(*retval < 0)) {

			int i;



			for (i = 0; i < j; i++)
@@ -567,9 +552,21 @@ static int __cpuinit detect_cache_attributes(unsigned int cpu) 
		}

		cache_shared_cpu_map_setup(cpu, j);

	}

	set_cpus_allowed_ptr(current, &oldmask);

}



static int __cpuinit detect_cache_attributes(unsigned int cpu)

{

	int			retval;



	if (num_cache_leaves == 0)

		return -ENOENT;



	per_cpu(cpuid4_info, cpu) = kzalloc(

	    sizeof(struct _cpuid4_info) * num_cache_leaves, GFP_KERNEL);

	if (per_cpu(cpuid4_info, cpu) == NULL)

		return -ENOMEM;



out:

	smp_call_function_single(cpu, get_cpu_leaves, &retval, true);

	if (retval) {

		kfree(per_cpu(cpuid4_info, cpu));

		per_cpu(cpuid4_info, cpu) = NULL;