s390/topology: honour nr_cpu_ids when adding CPUs

When SMT thread CPUs are added to CPU masks the nr_cpu_ids
limit is not checked and could be exceeded. This leads to
a warning for example if CONFIG_DEBUG_PER_CPU_MAPS is set
and the command line parameter nr_cpus is set to 1.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 9fd1953..68adf1d 100644 (file)
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -95,7 +95,7 @@ out:
 static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
 {
        static cpumask_t mask;
-       int i;
+       unsigned int max_cpu;
 
        cpumask_clear(&mask);
        if (!cpumask_test_cpu(cpu, &cpu_setup_mask))
@@ -104,9 +104,10 @@ static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
        if (topology_mode != TOPOLOGY_MODE_HW)
                goto out;
        cpu -= cpu % (smp_cpu_mtid + 1);
-       for (i = 0; i <= smp_cpu_mtid; i++) {
-               if (cpumask_test_cpu(cpu + i, &cpu_setup_mask))
-                       cpumask_set_cpu(cpu + i, &mask);
+       max_cpu = min(cpu + smp_cpu_mtid, nr_cpu_ids - 1);
+       for (; cpu <= max_cpu; cpu++) {
+               if (cpumask_test_cpu(cpu, &cpu_setup_mask))
+                       cpumask_set_cpu(cpu, &mask);
        }
 out:
        cpumask_copy(dst, &mask);
@@ -123,25 +124,26 @@ static void add_cpus_to_mask(struct topology_core *tl_core,
        unsigned int core;
 
        for_each_set_bit(core, &tl_core->mask, TOPOLOGY_CORE_BITS) {
-               unsigned int rcore;
-               int lcpu, i;
+               unsigned int max_cpu, rcore;
+               int cpu;
 
                rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
-               lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
-               if (lcpu < 0)
+               cpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
+               if (cpu < 0)
                        continue;
-               for (i = 0; i <= smp_cpu_mtid; i++) {
-                       topo = &cpu_topology[lcpu + i];
+               max_cpu = min(cpu + smp_cpu_mtid, nr_cpu_ids - 1);
+               for (; cpu <= max_cpu; cpu++) {
+                       topo = &cpu_topology[cpu];
                        topo->drawer_id = drawer->id;
                        topo->book_id = book->id;
                        topo->socket_id = socket->id;
                        topo->core_id = rcore;
-                       topo->thread_id = lcpu + i;
+                       topo->thread_id = cpu;
                        topo->dedicated = tl_core->d;
-                       cpumask_set_cpu(lcpu + i, &drawer->mask);
-                       cpumask_set_cpu(lcpu + i, &book->mask);
-                       cpumask_set_cpu(lcpu + i, &socket->mask);
-                       smp_cpu_set_polarization(lcpu + i, tl_core->pp);
+                       cpumask_set_cpu(cpu, &drawer->mask);
+                       cpumask_set_cpu(cpu, &book->mask);
+                       cpumask_set_cpu(cpu, &socket->mask);
+                       smp_cpu_set_polarization(cpu, tl_core->pp);
                }
        }
 }