ARM: cpuidle: Refactor rollback operations if init fails

If init fails, we need execute two levels rollback operations: the first
level is for the failed CPU rollback operations, the second level is to
iterate all succeeded CPUs to cancel their registration; currently the
code uses one function to finish these two levels rollback operations.

This commit is to refactor rollback operations, so it adds a new
function arm_idle_init_cpu() to encapsulate one specified CPU driver
registration and rollback the first level operations; and use function
arm_idle_init() to iterate all CPUs and finish the second level's
rollback operations.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 82 insertions, 63 deletions

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index f47c54546752..ddee1b601b89 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -72,79 +72,74 @@ static const struct of_device_id arm_idle_state_match[] __initconst = {
 };
 
 /*
- * arm_idle_init
+ * arm_idle_init_cpu
  *
  * Registers the arm specific cpuidle driver with the cpuidle
  * framework. It relies on core code to parse the idle states
  * and initialize them using driver data structures accordingly.
  */
-static int __init arm_idle_init(void)
+static int __init arm_idle_init_cpu(int cpu)
 {
-        int cpu, ret;
+        int ret;
         struct cpuidle_driver *drv;
         struct cpuidle_device *dev;
 
-        for_each_possible_cpu(cpu) {
+        drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
+        if (!drv)
+                return -ENOMEM;
 
-                drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
-                if (!drv) {
-                        ret = -ENOMEM;
-                        goto out_fail;
-                }
-
-                drv->cpumask = (struct cpumask *)cpumask_of(cpu);
-
-                /*
-                 * Initialize idle states data, starting at index 1.  This
-                 * driver is DT only, if no DT idle states are detected (ret
-                 * == 0) let the driver initialization fail accordingly since
-                 * there is no reason to initialize the idle driver if only
-                 * wfi is supported.
-                 */
-                ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
-                if (ret <= 0) {
-                        ret = ret ? : -ENODEV;
-                        goto out_kfree_drv;
-                }
-
-                ret = cpuidle_register_driver(drv);
-                if (ret) {
-                        pr_err("Failed to register cpuidle driver\n");
-                        goto out_kfree_drv;
-                }
-
-                /*
-                 * Call arch CPU operations in order to initialize
-                 * idle states suspend back-end specific data
-                 */
-                ret = arm_cpuidle_init(cpu);
-
-                /*
-                 * Skip the cpuidle device initialization if the reported
-                 * failure is a HW misconfiguration/breakage (-ENXIO).
-                 */
-                if (ret == -ENXIO)
-                        continue;
-
-                if (ret) {
-                        pr_err("CPU %d failed to init idle CPU ops\n", cpu);
-                        goto out_unregister_drv;
-                }
-
-                dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-                if (!dev) {
-                        pr_err("Failed to allocate cpuidle device\n");
-                        ret = -ENOMEM;
-                        goto out_unregister_drv;
-                }
-                dev->cpu = cpu;
-
-                ret = cpuidle_register_device(dev);
-                if (ret) {
-                        pr_err("Failed to register cpuidle device for CPU %d\n",
-                               cpu);
-                        goto out_kfree_dev;
-                }
+        drv->cpumask = (struct cpumask *)cpumask_of(cpu);
+
+        /*
+         * Initialize idle states data, starting at index 1.  This
+         * driver is DT only, if no DT idle states are detected (ret
+         * == 0) let the driver initialization fail accordingly since
+         * there is no reason to initialize the idle driver if only
+         * wfi is supported.
+         */
+        ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
+        if (ret <= 0) {
+                ret = ret ? : -ENODEV;
+                goto out_kfree_drv;
+        }
+
+        ret = cpuidle_register_driver(drv);
+        if (ret) {
+                pr_err("Failed to register cpuidle driver\n");
+                goto out_kfree_drv;
+        }
+
+        /*
+         * Call arch CPU operations in order to initialize
+         * idle states suspend back-end specific data
+         */
+        ret = arm_cpuidle_init(cpu);
+
+        /*
+         * Skip the cpuidle device initialization if the reported
+         * failure is a HW misconfiguration/breakage (-ENXIO).
+         */
+        if (ret == -ENXIO)
+                return 0;
+
+        if (ret) {
+                pr_err("CPU %d failed to init idle CPU ops\n", cpu);
+                goto out_unregister_drv;
+        }
+
+        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+        if (!dev) {
+                pr_err("Failed to allocate cpuidle device\n");
+                ret = -ENOMEM;
+                goto out_unregister_drv;
+        }
+        dev->cpu = cpu;
+
+        ret = cpuidle_register_device(dev);
+        if (ret) {
+                pr_err("Failed to register cpuidle device for CPU %d\n",
+                       cpu);
+                goto out_kfree_dev;
         }
 
         return 0;
@@ -155,6 +150,30 @@ out_unregister_drv:
         cpuidle_unregister_driver(drv);
 out_kfree_drv:
         kfree(drv);
+        return ret;
+}
+
+/*
+ * arm_idle_init - Initializes arm cpuidle driver
+ *
+ * Initializes arm cpuidle driver for all CPUs, if any CPU fails
+ * to register cpuidle driver then rollback to cancel all CPUs
+ * registeration.
+ */
+static int __init arm_idle_init(void)
+{
+        int cpu, ret;
+        struct cpuidle_driver *drv;
+        struct cpuidle_device *dev;
+
+        for_each_possible_cpu(cpu) {
+                ret = arm_idle_init_cpu(cpu);
+                if (ret)
+                        goto out_fail;
+        }
+
+        return 0;
+
 out_fail:
         while (--cpu >= 0) {
                 dev = per_cpu(cpuidle_devices, cpu);