Re: [PATCH 1/2] linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>

From: Paul Cercueil
Date: Fri Apr 09 2021 - 04:15:52 EST


Hi Masahiro,

Le ven. 9 avril 2021 à 5:58, Masahiro Yamada <masahiroy@xxxxxxxxxx> a écrit :
<linux/kconfig.h> is included from all the kernel-space source files,
including C, assembly, linker scripts. It is intended to contain minimal
set of macros to evaluate CONFIG options.

IF_ENABLED() is an intruder here because (x ? y : z) is C code, which
should not be included from assembly files or linker scripts.

Also, <linux/kconfig.h> is no longer self-contained because NULL is
defined in <linux/stddef.h>.

Move IF_ENABLED() out to <linux/kernel.h> as PTR_IF().

PTR_IF(IS_ENABLED(CONFIG_FOO), ...) is slightly longer than
IF_ENABLED(CONFIG_FOO, ...), but it is not a big deal because
sub-systems often define dedicated macros such as of_match_ptr(),
pm_ptr() etc. for common use-cases.

What's the idea behind changing IF_ENABLED() to PTR_IF()? You didn't explain that. What's wrong with IF_ENABLED()?

Cheers,
-Paul

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

drivers/pinctrl/pinctrl-ingenic.c | 20 ++++++++++----------
include/linux/kconfig.h | 6 ------
include/linux/kernel.h | 2 ++
3 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-ingenic.c b/drivers/pinctrl/pinctrl-ingenic.c
index f2746125b077..b21e2ae4528d 100644
--- a/drivers/pinctrl/pinctrl-ingenic.c
+++ b/drivers/pinctrl/pinctrl-ingenic.c
@@ -2496,43 +2496,43 @@ static int __init ingenic_pinctrl_probe(struct platform_device *pdev)
static const struct of_device_id ingenic_pinctrl_of_match[] = {
{
.compatible = "ingenic,jz4740-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_JZ4740, &jz4740_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4740), &jz4740_chip_info)
},
{
.compatible = "ingenic,jz4725b-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_JZ4725B, &jz4725b_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4725B), &jz4725b_chip_info)
},
{
.compatible = "ingenic,jz4760-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_JZ4760, &jz4760_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4760), &jz4760_chip_info)
},
{
.compatible = "ingenic,jz4760b-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_JZ4760, &jz4760_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4760), &jz4760_chip_info)
},
{
.compatible = "ingenic,jz4770-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_JZ4770, &jz4770_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4770), &jz4770_chip_info)
},
{
.compatible = "ingenic,jz4780-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_JZ4780, &jz4780_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_JZ4780), &jz4780_chip_info)
},
{
.compatible = "ingenic,x1000-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_X1000, &x1000_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1000), &x1000_chip_info)
},
{
.compatible = "ingenic,x1000e-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_X1000, &x1000_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1000), &x1000_chip_info)
},
{
.compatible = "ingenic,x1500-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_X1500, &x1500_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1500), &x1500_chip_info)
},
{
.compatible = "ingenic,x1830-pinctrl",
- .data = IF_ENABLED(CONFIG_MACH_X1830, &x1830_chip_info)
+ .data = PTR_IF(IS_ENABLED(CONFIG_MACH_X1830), &x1830_chip_info)
},
{ /* sentinel */ },
};
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index 24a59cb06963..cc8fa109cfa3 100644
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -70,10 +70,4 @@
*/
#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))

-/*
- * IF_ENABLED(CONFIG_FOO, ptr) evaluates to (ptr) if CONFIG_FOO is set to 'y'
- * or 'm', NULL otherwise.
- */
-#define IF_ENABLED(option, ptr) (IS_ENABLED(option) ? (ptr) : NULL)
-
#endif /* __LINUX_KCONFIG_H */
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5b7ed6dc99ac..8685ca4cf287 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -38,6 +38,8 @@
#define PTR_ALIGN_DOWN(p, a) ((typeof(p))ALIGN_DOWN((unsigned long)(p), (a)))
#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)

+#define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
+
/* generic data direction definitions */
#define READ 0
#define WRITE 1
--
2.27.0