Yinghai Lu <yinghai@xxxxxxxxxx> writes:
> On 03/29/2010 09:43 PM, Eric W. Biederman wrote:
>> Yinghai Lu <yinghai@xxxxxxxxxx> writes:
>>
>>> On Mon, Mar 29, 2010 at 4:20 PM, Eric W. Biederman
>>> <ebiederm@xxxxxxxxxxxx> wrote:
>>>> From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
>>>>
>>>> Use the global gsi_end value now that all ioapics have
>>>> valid gsi numbers instead of a combination of acpi_probe_gsi
>>>> and walking all of the ioapics and couting their number of
>>>> entries by hand if acpi_probe_gsi gave us an answer we did
>>>> not like.
>>>>
>>>> This fixes a small bug in probe_nr_irqs_gsi. Previously
>>>> acpi_probe_gsi unnecessarily added 1 to the maximum
>>>> gsi_end value. gsi_end is already one past the end of
>>>> the number of gsi's so the additional increment was
>>>> superfluous.
>>>>
>>>> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
>>>> ---
>>>> arch/x86/include/asm/mpspec.h | 6 ------
>>>> arch/x86/kernel/acpi/boot.c | 23 -----------------------
>>>> arch/x86/kernel/apic/io_apic.c | 17 +++--------------
>>>> 3 files changed, 3 insertions(+), 43 deletions(-)
>>>>
>>>> diff --git a/arch/x86/include/asm/mpspec.h b/arch/x86/include/asm/mpspec.h
>>>> index 29994f0..c82868e 100644
>>>> --- a/arch/x86/include/asm/mpspec.h
>>>> +++ b/arch/x86/include/asm/mpspec.h
>>>> @@ -105,12 +105,6 @@ extern void mp_config_acpi_legacy_irqs(void);
>>>> struct device;
>>>> extern int mp_register_gsi(struct device *dev, u32 gsi, int edge_level,
>>>> int active_high_low);
>>>> -extern int acpi_probe_gsi(void);
>>>> -#else /* !CONFIG_ACPI: */
>>>> -static inline int acpi_probe_gsi(void)
>>>> -{
>>>> - return 0;
>>>> -}
>>>> #endif /* CONFIG_ACPI */
>>>>
>>>> #define PHYSID_ARRAY_SIZE BITS_TO_LONGS(MAX_APICS)
>>>> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
>>>> index 9c48e99..0e514a1 100644
>>>> --- a/arch/x86/kernel/acpi/boot.c
>>>> +++ b/arch/x86/kernel/acpi/boot.c
>>>> @@ -875,29 +875,6 @@ static int __init acpi_parse_madt_lapic_entries(void)
>>>> extern int es7000_plat;
>>>> #endif
>>>>
>>>> -int __init acpi_probe_gsi(void)
>>>> -{
>>>> - int idx;
>>>> - int gsi;
>>>> - int max_gsi = 0;
>>>> -
>>>> - if (acpi_disabled)
>>>> - return 0;
>>>> -
>>>> - if (!acpi_ioapic)
>>>> - return 0;
>>>> -
>>>> - max_gsi = 0;
>>>> - for (idx = 0; idx < nr_ioapics; idx++) {
>>>> - gsi = mp_gsi_routing[idx].gsi_end;
>>>> -
>>>> - if (gsi > max_gsi)
>>>> - max_gsi = gsi;
>>>> - }
>>>> -
>>>> - return max_gsi + 1;
>>>> -}
>>>> -
>>>> static void assign_to_mp_irq(struct mpc_intsrc *m,
>>>> struct mpc_intsrc *mp_irq)
>>>> {
>>>> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
>>>> index 996cf8f..b57b7a3 100644
>>>> --- a/arch/x86/kernel/apic/io_apic.c
>>>> +++ b/arch/x86/kernel/apic/io_apic.c
>>>> @@ -3837,22 +3837,11 @@ int __init io_apic_get_redir_entries (int ioapic)
>>>>
>>>> void __init probe_nr_irqs_gsi(void)
>>>> {
>>>> - int nr = 0;
>>>> + int nr;
>>>>
>>>> - nr = acpi_probe_gsi();
>>>> - if (nr > nr_irqs_gsi) {
>>>> + nr = gsi_end;
>>>
>>> you may need +1 here
>>
>> As documented in my comment that extra +1 has every appearance of a
>> bug. Nothing is at gsi_end. gsi_end is already at 1 past the last in
>> use gsi. Therefore an extra +1 puts us two past the end for no
>> apparent reason.
>
> io_apic_get_redir_entries(), and io apic register readingout will return 23 if the total entries is 24.
Good catch. I don't know if I have ever seen a function with a name to function
correspondence. Apparently sfi.c also got this wrong when it was written.
and I missed the +1 in other places.
I guess this calls for another patch way at the beginning of my series that fixes
this brain damage.
Eric
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