[PATCH] hv: vmbus: mark PM functions as __maybe_unused

[PATCH] hv: vmbus: mark PM functions as __maybe_unused

[Arnd Bergmann]

When CONFIG_PM is disabled, we get a couple of harmless warnings:

drivers/hv/vmbus_drv.c:918:12: error: unused function 'vmbus_suspend' [-Werror,-Wunused-function]
drivers/hv/vmbus_drv.c:937:12: error: unused function 'vmbus_resume' [-Werror,-Wunused-function]
drivers/hv/vmbus_drv.c:2128:12: error: unused function 'vmbus_bus_suspend' [-Werror,-Wunused-function]
drivers/hv/vmbus_drv.c:2208:12: error: unused function 'vmbus_bus_resume' [-Werror,-Wunused-function]

Mark these functions __maybe_unused to let gcc drop them silently.

Fixes: f53335e3289f ("Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation")
Fixes: 271b2224d42f ("Drivers: hv: vmbus: Implement suspend/resume for VSC drivers for hibernation")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/hv/vmbus_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 391f0b225c9a..2542eb1f872b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -915,7 +915,7 @@ static void vmbus_shutdown(struct device *child_device)
 /*
  * vmbus_suspend - Suspend a vmbus device
  */
-static int vmbus_suspend(struct device *child_device)
+static int __maybe_unused vmbus_suspend(struct device *child_device)
 {
 	struct hv_driver *drv;
 	struct hv_device *dev = device_to_hv_device(child_device);
@@ -934,7 +934,7 @@ static int vmbus_suspend(struct device *child_device)
 /*
  * vmbus_resume - Resume a vmbus device
  */
-static int vmbus_resume(struct device *child_device)
+static int __maybe_unused vmbus_resume(struct device *child_device)
 {
 	struct hv_driver *drv;
 	struct hv_device *dev = device_to_hv_device(child_device);
@@ -2125,7 +2125,7 @@ static int vmbus_acpi_add(struct acpi_device *device)
 	return ret_val;
 }
 
-static int vmbus_bus_suspend(struct device *dev)
+static int __maybe_unused vmbus_bus_suspend(struct device *dev)
 {
 	struct vmbus_channel *channel, *sc;
 	unsigned long flags;
@@ -2205,7 +2205,7 @@ static int vmbus_bus_suspend(struct device *dev)
 	return 0;
 }
 
-static int vmbus_bus_resume(struct device *dev)
+static int __maybe_unused vmbus_bus_resume(struct device *dev)
 {
 	struct vmbus_channel_msginfo *msginfo;
 	size_t msgsize;
-- 
2.20.0

RE: [PATCH] hv: vmbus: mark PM functions as __maybe_unused

[Dexuan Cui]

> From: Arnd Bergmann <arnd@arndb.de>
> Sent: Wednesday, September 18, 2019 1:01 PM
> 
> When CONFIG_PM is disabled, we get a couple of harmless warnings:
> 
> drivers/hv/vmbus_drv.c:918:12: error: unused function 'vmbus_suspend'
> [-Werror,-Wunused-function]
> drivers/hv/vmbus_drv.c:937:12: error: unused function 'vmbus_resume'
> [-Werror,-Wunused-function]
> drivers/hv/vmbus_drv.c:2128:12: error: unused function 'vmbus_bus_suspend'
> [-Werror,-Wunused-function]
> drivers/hv/vmbus_drv.c:2208:12: error: unused function 'vmbus_bus_resume'
> [-Werror,-Wunused-function]
> 
> Mark these functions __maybe_unused to let gcc drop them silently.

Hi Arnd,
Thanks for reporting the issue!

If CONFIG_PM is not set, IMO it's better to comment out these functions. :-)

I'll post a patch for this with you Cc'd.

Thanks,
-- Dexuan