From: Jan Beulich <jbeulich@suse.com>
Date: Wed, 26 Mar 2025 11:31:33 +0000 (+0100)
Subject: x86/pmstat: fold two allocations in get_cpufreq_para()
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=a6bb5f145646ffe10536f030581260e8eae48e75;p=people%2Fandrewcoop%2Fxen.git

x86/pmstat: fold two allocations in get_cpufreq_para()

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@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/xen/drivers/acpi/pmstat.c b/xen/drivers/acpi/pmstat.c
index df309e27b4..aae94529ab 100644
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -193,11 +193,10 @@ static int get_cpufreq_para(struct xen_sysctl_pm_op *op)
     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_sysctl_pm_op *op)
         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;