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Message-ID: <e4288a46-5cb2-8797-bf30-c14765af8ce3@oracle.com>
Date: Thu, 29 Jun 2023 08:25:08 -0500
From: Eric DeVolder <eric.devolder@...cle.com>
To: linux-kernel@...r.kernel.org, david@...hat.com, osalvador@...e.de,
corbet@....net, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, x86@...nel.org, bhe@...hat.com,
ebiederm@...ssion.com, kexec@...ts.infradead.org
Cc: hpa@...or.com, gregkh@...uxfoundation.org, rafael@...nel.org,
vgoyal@...hat.com, dyoung@...hat.com, lf32.dev@...il.com,
akpm@...ux-foundation.org, naveen.n.rao@...ux.vnet.ibm.com,
zohar@...ux.ibm.com, bhelgaas@...gle.com, vbabka@...e.cz,
tiwai@...e.de, seanjc@...gle.com, linux@...ssschuh.net,
vschneid@...hat.com, linux-mm@...ck.org, linux-doc@...r.kernel.org,
sourabhjain@...ux.ibm.com, konrad.wilk@...cle.com,
boris.ostrovsky@...cle.com
Subject: Re: [PATCH v24 01/10] drivers/base: refactor cpu.c to use
.is_visible()
I still need to convert the ifdefs within the functions to IS_ENABLED(), my apologies.
eric
On 6/28/23 13:52, Eric DeVolder wrote:
> Greg Kroah-Hartman requested that this file use the .is_visible()
> method instead of #ifdefs for the attributes in cpu.c.
>
> static struct attribute *cpu_root_attrs[] = {
> #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
> &dev_attr_probe.attr,
> &dev_attr_release.attr,
> #endif
> &cpu_attrs[0].attr.attr,
> &cpu_attrs[1].attr.attr,
> &cpu_attrs[2].attr.attr,
> &dev_attr_kernel_max.attr,
> &dev_attr_offline.attr,
> &dev_attr_isolated.attr,
> #ifdef CONFIG_NO_HZ_FULL
> &dev_attr_nohz_full.attr,
> #endif
> #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
> &dev_attr_modalias.attr,
> #endif
> NULL
> };
>
> To that end:
> - the .is_visible() method is implemented, and IS_ENABLED(), rather
> than #ifdef, is used to determine the visibility of the attribute.
> - the DEVICE_ATTR() attributes are moved outside of #ifdefs, so that
> those structs are always present for the cpu_root_attrs[].
> - the #ifdefs guarding the attributes in the cpu_root_attrs[] are moved
> to the corresponding callback function; as the callback function must
> exist now that the attribute is always compiled-in (though not
> necessarily visible).
>
> No functionality change intended.
>
> Signed-off-by: Eric DeVolder <eric.devolder@...cle.com>
> ---
> drivers/base/cpu.c | 67 ++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 53 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index c1815b9dae68..75fa46a567a1 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -82,13 +82,14 @@ void unregister_cpu(struct cpu *cpu)
> per_cpu(cpu_sys_devices, logical_cpu) = NULL;
> return;
> }
> +#endif /* CONFIG_HOTPLUG_CPU */
>
> -#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
> static ssize_t cpu_probe_store(struct device *dev,
> struct device_attribute *attr,
> const char *buf,
> size_t count)
> {
> +#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
> ssize_t cnt;
> int ret;
>
> @@ -100,6 +101,9 @@ static ssize_t cpu_probe_store(struct device *dev,
>
> unlock_device_hotplug();
> return cnt;
> +#else
> + return 0;
> +#endif
> }
>
> static ssize_t cpu_release_store(struct device *dev,
> @@ -107,6 +111,7 @@ static ssize_t cpu_release_store(struct device *dev,
> const char *buf,
> size_t count)
> {
> +#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
> ssize_t cnt;
> int ret;
>
> @@ -118,12 +123,13 @@ static ssize_t cpu_release_store(struct device *dev,
>
> unlock_device_hotplug();
> return cnt;
> +#else
> + return 0;
> +#endif
> }
>
> static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
> static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
> -#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
> -#endif /* CONFIG_HOTPLUG_CPU */
>
> #ifdef CONFIG_KEXEC
> #include <linux/kexec.h>
> @@ -273,14 +279,16 @@ static ssize_t print_cpus_isolated(struct device *dev,
> }
> static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
>
> -#ifdef CONFIG_NO_HZ_FULL
> static ssize_t print_cpus_nohz_full(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> +#ifdef CONFIG_NO_HZ_FULL
> return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
> +#else
> + return 0;
> +#endif
> }
> static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
> -#endif
>
> static void cpu_device_release(struct device *dev)
> {
> @@ -301,12 +309,12 @@ static void cpu_device_release(struct device *dev)
> */
> }
>
> -#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
> static ssize_t print_cpu_modalias(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> {
> int len = 0;
> +#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
> u32 i;
>
> len += sysfs_emit_at(buf, len,
> @@ -322,9 +330,11 @@ static ssize_t print_cpu_modalias(struct device *dev,
> len += sysfs_emit_at(buf, len, ",%04X", i);
> }
> len += sysfs_emit_at(buf, len, "\n");
> +#endif
> return len;
> }
>
> +#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
> static int cpu_uevent(const struct device *dev, struct kobj_uevent_env *env)
> {
> char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> @@ -451,32 +461,61 @@ struct device *cpu_device_create(struct device *parent, void *drvdata,
> }
> EXPORT_SYMBOL_GPL(cpu_device_create);
>
> -#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
> static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
> -#endif
>
> static struct attribute *cpu_root_attrs[] = {
> -#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
> &dev_attr_probe.attr,
> &dev_attr_release.attr,
> -#endif
> &cpu_attrs[0].attr.attr,
> &cpu_attrs[1].attr.attr,
> &cpu_attrs[2].attr.attr,
> &dev_attr_kernel_max.attr,
> &dev_attr_offline.attr,
> &dev_attr_isolated.attr,
> -#ifdef CONFIG_NO_HZ_FULL
> &dev_attr_nohz_full.attr,
> -#endif
> -#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
> &dev_attr_modalias.attr,
> -#endif
> NULL
> };
>
> +static umode_t
> +cpu_root_attr_is_visible(struct kobject *kobj,
> + struct attribute *attr, int unused)
> +{
> + umode_t mode = attr->mode;
> +
> + if (IS_ENABLED(CONFIG_ARCH_CPU_PROBE_RELEASE)) {
> + if (attr == &dev_attr_probe.attr)
> + return mode;
> + if (attr == &dev_attr_release.attr)
> + return mode;
> + }
> + if (attr == &cpu_attrs[0].attr.attr)
> + return mode;
> + if (attr == &cpu_attrs[1].attr.attr)
> + return mode;
> + if (attr == &cpu_attrs[2].attr.attr)
> + return mode;
> + if (attr == &dev_attr_kernel_max.attr)
> + return mode;
> + if (attr == &dev_attr_offline.attr)
> + return mode;
> + if (attr == &dev_attr_isolated.attr)
> + return mode;
> + if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
> + if (attr == &dev_attr_nohz_full.attr)
> + return mode;
> + }
> + if (IS_ENABLED(CONFIG_GENERIC_CPU_AUTOPROBE)) {
> + if (attr == &dev_attr_modalias.attr)
> + return mode;
> + }
> +
> + return 0;
> +}
> +
> static const struct attribute_group cpu_root_attr_group = {
> .attrs = cpu_root_attrs,
> + .is_visible = cpu_root_attr_is_visible,
> };
>
> static const struct attribute_group *cpu_root_attr_groups[] = {
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