ACPI: Avoid wiping out pr->performance during preregistering

When cpufreq driver call acpi_processor_preregister_performance() , function
will clean up pr->performance even if there is possibly already registered
other cpufreq driver. The patch fix this potential problem. It also remove
double checks in P domain basic validity code and move these checks to function
where _PSD data is captured.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 21 insertions, 25 deletions

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 9cc769b587ff..215f1bf7d4c1 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -479,6 +479,13 @@ static int acpi_processor_get_psd(struct acpi_processor	*pr)
                 goto end;
         }
 
+        if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
+            pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
+            pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
+                printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
+                result = -EFAULT;
+                goto end;
+        }
 end:
         kfree(buffer.pointer);
         return result;
@@ -501,9 +508,10 @@ int acpi_processor_preregister_performance(
 
         mutex_lock(&performance_mutex);
 
-        retval = 0;
-
-        /* Call _PSD for all CPUs */
+        /*
+         * Check if another driver has already registered, and abort before
+         * changing pr->performance if it has. Check input data as well.
+         */
         for_each_possible_cpu(i) {
                 pr = per_cpu(processors, i);
                 if (!pr) {
@@ -513,13 +521,20 @@ int acpi_processor_preregister_performance(
 
                 if (pr->performance) {
                         retval = -EBUSY;
-                        continue;
+                        goto err_out;
                 }
 
                 if (!performance || !percpu_ptr(performance, i)) {
                         retval = -EINVAL;
-                        continue;
+                        goto err_out;
                 }
+        }
+
+        /* Call _PSD for all CPUs */
+        for_each_possible_cpu(i) {
+                pr = per_cpu(processors, i);
+                if (!pr)
+                        continue;
 
                 pr->performance = percpu_ptr(performance, i);
                 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
@@ -535,26 +550,6 @@ int acpi_processor_preregister_performance(
          * Now that we have _PSD data from all CPUs, lets setup P-state 
          * domain info.
          */
-        for_each_possible_cpu(i) {
-                pr = per_cpu(processors, i);
-                if (!pr)
-                        continue;
-
-                /* Basic validity check for domain info */
-                pdomain = &(pr->performance->domain_info);
-                if ((pdomain->revision != ACPI_PSD_REV0_REVISION) ||
-                    (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES)) {
-                        retval = -EINVAL;
-                        goto err_ret;
-                }
-                if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
-                    pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
-                    pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
-                        retval = -EINVAL;
-                        goto err_ret;
-                }
-        }
-
         cpumask_clear(covered_cpus);
         for_each_possible_cpu(i) {
                 pr = per_cpu(processors, i);
@@ -643,6 +638,7 @@ err_ret:
                 pr->performance = NULL; /* Will be set for real in register */
         }
 
+err_out:
         mutex_unlock(&performance_mutex);
         free_cpumask_var(covered_cpus);
         return retval;