[PATCH v2 1/3] PM: runtime: Wrapper macros for ACQUIRE()/ACQUIRE_ERR()

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Add wrapper macros for ACQUIRE()/ACQUIRE_ERR() and runtime PM
usage counter guards introduced recently: pm_runtime_active_try,
pm_runtime_active_auto_try, pm_runtime_active_try_enabled, and
pm_runtime_active_auto_try_enabled.

The new macros should be more straightforward to use.

For example, they can be used for rewriting a piece of code like below:

        ACQUIRE(pm_runtime_active_try, pm)(dev);
        if ((ret = ACQUIRE_ERR(pm_runtime_active_try, &pm)))
                return ret;

in the following way:

        PM_RUNTIME_ACQUIRE(dev, pm);
        if ((ret = PM_RUNTIME_ACQUIRE_ERR(&pm)))
                return ret;

If the original code does not care about the specific error code
returned when attepmting to resume the device:

        ACQUIRE(pm_runtime_active_try, pm)(dev);
        if (ACQUIRE_ERR(pm_runtime_active_try, &pm))
                return -ENXIO;

it may be changed like this:

        PM_RUNTIME_ACQUIRE(dev, pm);
        if (PM_RUNTIME_ACQUIRE_ERR(&pm))
                return -ENXIO;

Link: https://lore.kernel.org/linux-pm/5068916.31r3eYUQgx@rafael.j.wysocki/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---

v1 -> v2:
   * The new macros take the guard variable name as a parameter.
   * The new ERR macro takes a guard variable pointer as a parameter (Dan).
   * Added underscore prefix to the macro parameter names.

---
 include/linux/pm_runtime.h |   24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -637,6 +637,30 @@ DEFINE_GUARD_COND(pm_runtime_active_auto
 DEFINE_GUARD_COND(pm_runtime_active_auto, _try_enabled,
 		  pm_runtime_resume_and_get(_T), _RET == 0)
 
+/* ACQUIRE() wrapper macros for the guards defined above. */
+
+#define PM_RUNTIME_ACQUIRE(_dev, _var)			\
+	ACQUIRE(pm_runtime_active_try, _var)(_dev)
+
+#define PM_RUNTIME_ACQUIRE_AUTOSUSPEND(_dev, _var)	\
+	ACQUIRE(pm_runtime_active_auto_try, _var)(_dev)
+
+#define PM_RUNTIME_ACQUIRE_IF_ENABLED(_dev, _var)	\
+	ACQUIRE(pm_runtime_active_try_enabled, _var)(_dev)
+
+#define PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND(_dev, _var)	\
+	ACQUIRE(pm_runtime_active_auto_try_enabled, _var)(_dev)
+
+/*
+ * ACQUIRE_ERR() wrapper macro for guard pm_runtime_active.
+ *
+ * Always check PM_RUNTIME_ACQUIRE_ERR() after using one of the
+ * PM_RUNTIME_ACQUIRE*() macros defined above (yes, it can be used with
+ * any of them) and if it is nonzero, avoid accessing the given device.
+ */
+#define PM_RUNTIME_ACQUIRE_ERR(_var_ptr)	\
+	ACQUIRE_ERR(pm_runtime_active, _var_ptr)
+
 /**
  * pm_runtime_put_sync - Drop device usage counter and run "idle check" if 0.
  * @dev: Target device.