On 2021/2/5 0:10, Bjorn Helgaas wrote:
[+cc Masahiro, Michal, linux-kbuild, linux-kernel]
On Thu, Feb 04, 2021 at 07:30:15PM +0800, Yicong Yang wrote:
From: Junhao He <hejunhao2@hisilicon.com>
Use subdir-ccflags-* instead of ccflags-* to inherit the debug settings from Kconfig when traversing subdirectories.
So I guess the current behavior is:
If CONFIG_PCI_DEBUG=y, add -DDEBUG to CFLAGS in the current directory, but not in any subdirectories
and the behavior after this patch is:
If CONFIG_PCI_DEBUG=y, add -DDEBUG to CFLAGS in the current directory and any subdirectories
Is that right? That makes sense to me. I wonder if any other places have this issue?
that's right. we didn't check other places, but some have individual config in their sub-directory as you mentioned below.
'git grep "^ccflags.*-DDEBUG"' finds a few cases where subdirectories use their own debug config options, e.g.,
drivers/i2c/Makefile:ccflags-$(CONFIG_I2C_DEBUG_CORE) := -DDEBUG drivers/i2c/algos/Makefile:ccflags-$(CONFIG_I2C_DEBUG_ALGO) := -DDEBUG drivers/i2c/busses/Makefile:ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG drivers/i2c/muxes/Makefile:ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
But some have subdirectories that look like they probably should be included by using subdir-ccflags, e.g.,
drivers/base/Makefile:ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG drivers/base/power/Makefile:ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG # drivers/base/{firmware_loader,regmap,test}/ not included
drivers/hwmon/Makefile:ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG # drivers/hwmon/{occ,pmbus}/ not included
drivers/pps/Makefile:ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG drivers/pps/clients/Makefile:ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG # drivers/pps/generators/ not included
There are many more places that add -DDEBUG to ccflags-y that *don't* have subdirectories.
I wonder the default should be that we use subdir-ccflags all the time, and use ccflags only when we actually want different CONFIG_*_DEBUG options for subdirectories.
agree. if there is no debug config in the sub-directory, the config should be inherited from its parent directory using subdir-ccflags. we can post a separate serial to issue other places. Thanks, Yicong
Signed-off-by: Junhao He <hejunhao2@hisilicon.com> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> --- drivers/pci/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index 11cc794..d62c4ac 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -36,4 +36,4 @@ obj-$(CONFIG_PCI_ENDPOINT) += endpoint/ obj-y += controller/ obj-y += switch/
-ccflags-$(CONFIG_PCI_DEBUG) := -DDEBUG +subdir-ccflags-$(CONFIG_PCI_DEBUG) := -DDEBUG -- 2.8.1
.