On Wed, Dec 28, 2011 at 05:45:18PM +1100, Stephen Rothwell wrote:

Hi Greg,

After merging the driver-core tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:

arch/powerpc/platforms/cell/spu_base.c: In function 'spu_add_dev_attr':
arch/powerpc/platforms/cell/spu_base.c:533:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
cc1: all warnings being treated as errors
arch/powerpc/kernel/sysfs.c: In function 'topology_init':
arch/powerpc/kernel/sysfs.c:658:22: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c: In function 'register_cpu_online':
arch/powerpc/kernel/sysfs.c:346:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:380:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:384:22: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:388:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:391:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:394:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:397:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c:400:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
arch/powerpc/kernel/sysfs.c: In function 'cpu_add_dev_attr':
arch/powerpc/kernel/sysfs.c:532:21: error: ignoring return value of 'device_create_file', declared with attribute warn_unused_result [-Werror=unused-result]
cc1: all warnings being treated as errors

Caused by commit 8a25a2fd126c ("cpu: convert 'cpu' and 'machinecheck'
sysdev_class to a regular subsystem").   Powerpc builds parts of
arch/powerpc with -Werror.

Ok, I'll take off the warn_unused_result flag for device_create_file for
now, which should solve this, and your other build problems with the
driver-core tree.

drivers/base/cpu.c: In function 'cpu_is_hotpluggable':
drivers/base/cpu.c:272:9: error: implicit declaration of function 'get_cpu_sysdev' [-Werror=implicit-function-declaration]
drivers/base/cpu.c:272:27: warning: initialization makes pointer from integer without a cast [enabled by default]
drivers/base/cpu.c:273:16: error: 'struct cpu' has no member named 'sysdev'
drivers/base/cpu.c:273:16: warning: initialization from incompatible pointer type [enabled by default]
drivers/base/cpu.c:273:16: error: 'struct cpu' has no member named 'sysdev'
drivers/base/cpu.c:274:1: warning: control reaches end of non-void function [-Wreturn-type]

Caused by the above commit interacting with commit 2987557f52b9
("driver-core/cpu: Expose hotpluggability to the rest of the kernel")
from the tip tree.  This is will fix up in the merge commit next time.

Yeah, nothing I can do here about this, sorry.

So this should fix the build problems in the driver-core-next branch for
linux-next.

thanks,

greg k-h