[PATCH] x86/pmstat: fold two allocations in get_cpufreq_para()

[Jan Beulich <jbeulich@xxxxxxxx>]

There's little point in allocation two uint32_t[] arrays separately.
We'll need the bigger of the two anyway, and hence we can use that
bigger one also for transiently storing the smaller number of items.

While there also drop j (we can use i twice) and adjust the type of
the remaining two variables on that line.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -193,11 +193,10 @@ static int get_cpufreq_para(struct xen_s
     const struct processor_pminfo *pmpt;
     struct cpufreq_policy *policy;
     uint32_t gov_num = 0;
-    uint32_t *affected_cpus;
-    uint32_t *scaling_available_frequencies;
+    uint32_t *data;
     char     *scaling_available_governors;
     struct list_head *pos;
-    uint32_t cpu, i, j = 0;
+    unsigned int cpu, i = 0;
 
     pmpt = processor_pminfo[op->cpuid];
     policy = per_cpu(cpufreq_cpu_policy, op->cpuid);
@@ -219,25 +218,22 @@ static int get_cpufreq_para(struct xen_s
         return -EAGAIN;
     }
 
-    if ( !(affected_cpus = xzalloc_array(uint32_t, op->u.get_para.cpu_num)) )
+    if ( !(data = xzalloc_array(uint32_t,
+                                max(op->u.get_para.cpu_num,
+                                    op->u.get_para.freq_num))) )
         return -ENOMEM;
+
     for_each_cpu(cpu, policy->cpus)
-        affected_cpus[j++] = cpu;
+        data[i++] = cpu;
     ret = copy_to_guest(op->u.get_para.affected_cpus,
-                       affected_cpus, op->u.get_para.cpu_num);
-    xfree(affected_cpus);
-    if ( ret )
-        return ret;
+                        data, op->u.get_para.cpu_num);
 
-    if ( !(scaling_available_frequencies =
-           xzalloc_array(uint32_t, op->u.get_para.freq_num)) )
-        return -ENOMEM;
     for ( i = 0; i < op->u.get_para.freq_num; i++ )
-        scaling_available_frequencies[i] =
-                        pmpt->perf.states[i].core_frequency * 1000;
+        data[i] = pmpt->perf.states[i].core_frequency * 1000;
     ret = copy_to_guest(op->u.get_para.scaling_available_frequencies,
-                   scaling_available_frequencies, op->u.get_para.freq_num);
-    xfree(scaling_available_frequencies);
+                        data, op->u.get_para.freq_num) ?: ret;
+
+    xfree(data);
     if ( ret )
         return ret;