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Date: Sat, 31 Aug 2013 22:14:24 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Hanjun Guo <hanjun.guo@...aro.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Tony Luck <tony.luck@...el.com>,
Ingo Molnar <mingo@...hat.com>, linux-acpi@...r.kernel.org,
x86@...nel.org, linux-ia64@...r.kernel.org,
linux-kernel@...r.kernel.org, patches@...aro.org,
linaro-kernel@...ts.linaro.org, linaro-acpi@...ts.linaro.org,
Jiang Liu <jiang.liu@...wei.com>
Subject: Re: [PATCH 3/6] x86: simplify _acpi_map_lsapic()
On Saturday, August 31, 2013 06:15:58 PM Hanjun Guo wrote:
> From: Jiang Liu <jiang.liu@...wei.com>
>
> In acpi_register_lapic(), it will generates a new logical cpu
> number and maps to the local APIC id, this logical cpu number
> can be returned to simplify _acpi_map_lsapic() implementation.
>
> Signed-off-by: Jiang Liu <jiang.liu@...wei.com>
> Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>
> ---
> arch/x86/include/asm/mpspec.h | 2 +-
> arch/x86/kernel/acpi/boot.c | 48 +++++++++++++----------------------------
> arch/x86/kernel/apic/apic.c | 8 ++++---
> 3 files changed, 21 insertions(+), 37 deletions(-)
>
> diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h
> index 626cf70..3142a94 100644
> --- a/arch/x86/include/asm/mpspec.h
> +++ b/arch/x86/include/asm/mpspec.h
> @@ -94,7 +94,7 @@ static inline void early_reserve_e820_mpc_new(void) { }
> #define default_get_smp_config x86_init_uint_noop
> #endif
>
> -void generic_processor_info(int apicid, int version);
> +int generic_processor_info(int apicid, int version);
> #ifdef CONFIG_ACPI
> extern void mp_register_ioapic(int id, u32 address, u32 gsi_base);
> extern void mp_override_legacy_irq(u8 bus_irq, u8 polarity, u8 trigger,
> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
> index 3e186d1..ca73370 100644
> --- a/arch/x86/kernel/acpi/boot.c
> +++ b/arch/x86/kernel/acpi/boot.c
> @@ -195,24 +195,31 @@ static int __init acpi_parse_madt(struct acpi_table_header *table)
> return 0;
> }
>
> -static void acpi_register_lapic(int id, u8 enabled)
> +/**
> + * acpi_register_lapic - register a local apic and generates a logic cpu number
> + * @id: local apic id to register
> + * @enabled: this cpu is enabled or not
> + *
> + * Returns the logic cpu number which maps to the local apic
> + */
> +static int acpi_register_lapic(int id, u8 enabled)
> {
> unsigned int ver = 0;
>
> if (id >= (MAX_LOCAL_APIC-1)) {
> printk(KERN_INFO PREFIX "skipped apicid that is too big\n");
> - return;
> + return -1;
> }
>
> if (!enabled) {
> ++disabled_cpus;
> - return;
> + return -1;
> }
If this returned -EINVAL instead of just -1, ->
>
> if (boot_cpu_physical_apicid != -1U)
> ver = apic_version[boot_cpu_physical_apicid];
>
> - generic_processor_info(id, ver);
> + return generic_processor_info(id, ver);
-> and this too (on errors), -->
> }
>
> static int __init
> @@ -622,44 +629,19 @@ static void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
>
> static int _acpi_map_lsapic(acpi_handle handle, int physid, int *pcpu)
> {
> - cpumask_var_t tmp_map, new_map;
> int cpu;
> - int retval = -ENOMEM;
> -
> - if (!alloc_cpumask_var(&tmp_map, GFP_KERNEL))
> - goto out;
>
> - if (!alloc_cpumask_var(&new_map, GFP_KERNEL))
> - goto free_tmp_map;
> -
> - cpumask_copy(tmp_map, cpu_present_mask);
> - acpi_register_lapic(physid, ACPI_MADT_ENABLED);
> -
> - /*
> - * If acpi_register_lapic successfully generates a new logical cpu
> - * number, then the following will get us exactly what was mapped
> - */
> - cpumask_andnot(new_map, cpu_present_mask, tmp_map);
> - if (cpumask_empty(new_map)) {
> + cpu = acpi_register_lapic(physid, ACPI_MADT_ENABLED);
> + if (cpu == -1) {
> printk ("Unable to map lapic to logical cpu number\n");
> - retval = -EINVAL;
> - goto free_new_map;
> + return -EINVAL;
> }
--> then this could be
if (cpu < 0) {
...
return cpu;
}
>
> acpi_processor_set_pdc(handle);
> -
> - cpu = cpumask_first(new_map);
> acpi_map_cpu2node(handle, cpu, physid);
>
> *pcpu = cpu;
> - retval = 0;
> -
> -free_new_map:
> - free_cpumask_var(new_map);
> -free_tmp_map:
> - free_cpumask_var(tmp_map);
> -out:
> - return retval;
> + return 0;
> }
>
> /* wrapper to silence section mismatch warning */
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index eca89c5..87128778 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -2107,7 +2107,7 @@ void disconnect_bsp_APIC(int virt_wire_setup)
> apic_write(APIC_LVT1, value);
> }
>
> -void generic_processor_info(int apicid, int version)
> +int generic_processor_info(int apicid, int version)
> {
> int cpu, max = nr_cpu_ids;
> bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
> @@ -2127,7 +2127,7 @@ void generic_processor_info(int apicid, int version)
> " Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
>
> disabled_cpus++;
> - return;
> + return -1;
> }
>
> if (num_processors >= nr_cpu_ids) {
> @@ -2138,7 +2138,7 @@ void generic_processor_info(int apicid, int version)
> " Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
>
> disabled_cpus++;
> - return;
> + return -1;
> }
>
> num_processors++;
> @@ -2183,6 +2183,8 @@ void generic_processor_info(int apicid, int version)
> #endif
> set_cpu_possible(cpu, true);
> set_cpu_present(cpu, true);
> +
> + return cpu;
> }
>
> int hard_smp_processor_id(void)
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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