[PATCH v1 1/3] PM: runtime: Introduce PM_RUNTIME_ACQUIRE_OR_FAIL() macro

["Rafael J. Wysocki" <rafael@kernel.org>]

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

There appears to be an emerging pattern in which guard
pm_runtime_active_try is used for resuming the given device and
incrementing its runtime PM usage counter if the resume has been
successful, that is followed by an ACQUIRE_ERR() check on the guard
variable and if that triggers, a specific error code is returned, for
example:

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

Introduce a macro called PM_RUNTIME_ACQUIRE_OR_FAIL() representing the
above sequence of statements that can be used to avoid code duplication
wherever that sequence would be used.

Use this macro right away in the PCI sysfs code where the above pattern
is already present.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

Admittedly, the new macro is slightly on the edge, but it really helps
reduce code duplication, so here it goes.

Any feedback (good, bad, ugly) will be appreciated.

Thanks!

---
 drivers/pci/pci-sysfs.c    |    4 +---
 include/linux/pm_runtime.h |    5 +++++
 2 files changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1517,9 +1517,7 @@ static ssize_t reset_method_store(struct
 		return count;
 	}
 
-	ACQUIRE(pm_runtime_active_try, pm)(dev);
-	if (ACQUIRE_ERR(pm_runtime_active_try, &pm))
-		return -ENXIO;
+	PM_RUNTIME_ACQUIRE_OR_FAIL(dev, -ENXIO);
 
 	if (sysfs_streq(buf, "default")) {
 		pci_init_reset_methods(pdev);
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -637,6 +637,11 @@ DEFINE_GUARD_COND(pm_runtime_active_auto
 DEFINE_GUARD_COND(pm_runtime_active_auto, _try_enabled,
 		  pm_runtime_resume_and_get(_T))
 
+#define PM_RUNTIME_ACQUIRE_OR_FAIL(dev, error)		\
+	ACQUIRE(pm_runtime_active_try, __pm)(dev);	\
+	if (ACQUIRE_ERR(pm_runtime_active_try, &__pm))	\
+		return error
+
 /**
  * pm_runtime_put_sync - Drop device usage counter and run "idle check" if 0.
  * @dev: Target device.