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Subject: Re: [PATCH 4/5] x86/platform/uv: Add deprecated messages to /proc
 info leaves
To:     Mike Travis <mike.travis@hpe.com>,
        Justin Ernst <justin.ernst@hpe.com>,
        Mark Gross <mgross@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, Steve Wahl <steve.wahl@hpe.com>
Cc:     Dimitri Sivanich <dimitri.sivanich@hpe.com>,
        Russ Anderson <russ.anderson@hpe.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Ilya Dryomov <idryomov@gmail.com>,
        linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org
References: <20201125172907.240996-1-mike.travis@hpe.com>
 <20201125172907.240996-5-mike.travis@hpe.com>
 <b0339696-049a-e46e-bcd4-079f1b13d725@redhat.com>
 <ebd8451a-5910-1da5-4792-2a3d2f59b348@hpe.com>
From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <3bc4d491-e4c9-132e-97ce-8acfbe9dc509@redhat.com>
Date:   Fri, 27 Nov 2020 19:06:12 +0100
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Hi,

On 11/27/20 3:58 PM, Mike Travis wrote:
> 
> 
> On 11/26/2020 2:45 AM, Hans de Goede wrote:
>> Hi,
>>
>> On 11/25/20 6:29 PM, Mike Travis wrote:
>>> Add "deprecated" message to any access to old /proc/sgi_uv/* leaves.
>>>
>>> Signed-off-by: Mike Travis <mike.travis@hpe.com>
>>> Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
>>> ---
>>> ? arch/x86/kernel/apic/x2apic_uv_x.c | 26 +++++++++++++++++++++++++-
>>> ? 1 file changed, 25 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
>>> index 48746031b39a..bfd77a00c2a1 100644
>>> --- a/arch/x86/kernel/apic/x2apic_uv_x.c
>>> +++ b/arch/x86/kernel/apic/x2apic_uv_x.c
>>> @@ -1615,21 +1615,45 @@ static void check_efi_reboot(void)
>>> ????????? reboot_type = BOOT_ACPI;
>>> ? }
>>> ? -/* Setup user proc fs files */
>>> +/*
>>> + * User proc fs file handling now deprecated.
>>> + * Recommend using /sys/firmware/sgi_uv/... instead.
>>> + */
>>> +static void proc_print_msg(int *flag, char *what, char *which)
>>> +{
>>> +??? if (*flag)
>>> +??????? return;
>>> +
>>> +??? pr_notice(
>>> +??????? "%s: using deprecated /proc/sgi_uv/%s, use /sys/firmware/sgi_uv/%s\n",
>>> +??????? current->comm, what, which ? which : what);
>>> +
>>> +??? *flag = 1;
>>> +}
>>> +
>>
>> You have just re-invented pr_notice_once, please just use pr_notice_once
>> directly in the _show functions.
> 
> I tried it both ways (actually with rate limiting as well).? The problem with using a static check in the error print function it will only print the first instance it encounters, not all of the references.
> 
> If I move it to the final output I need to replicate the verbiage of the format for every instance as you can't seem to combine the KERN_* level of printing and the pr_fmt reference of the format string.? I tried a few ways including just putting everything into a format character list. ?But what used to work (indirect format pointer) doesn't any more.? Or I didn't hit on the correct combination of KERN_* level and indirect format string.
> 
> The last combination was no print limiting which caused of course the error message to be output on every occurrence.? (NASA has 35,000 customers for their big systems, that's a lot of potential console messages.)? This really annoys them and we would get calls from those that don't have any means of changing this so they ask us.
> 
> So I just chose this method of accomplishing all goals, except of course using the higher level of print function (pr_notice_once).? But if you think method two ("use pr_notice_once directly in the _show function") is most favorable I will switch to that.

Yeah I think using that is much better then reinventing it, you can simply just write
out the 3 different messages which you are "formatting" now as static strings so you get:

	pr_notice_once("%s: using deprecated /proc/sgi_uv/hubbed, use /sys/firmware/sgi_uv/hub_type\n", current->comm);

	pr_notice_once("%s: using deprecated /proc/sgi_uv/hubless, use /sys/firmware/sgi_uv/hubless\n", current->comm);

	pr_notice_once("%s: using deprecated /proc/sgi_uv/archtype, use /sys/firmware/sgi_uv/archtype\n", current->comm);

Regards,

Hans


> 
>>
>> Regards,
>>
>> Hans
>>
>>
>>
>>
>>> ? static int __maybe_unused proc_hubbed_show(struct seq_file *file, void *data)
>>> ? {
>>> +??? static int flag;
>>> +
>>> +??? proc_print_msg(&flag, "hubbed", "hub_type");
>>> ????? seq_printf(file, "0x%x\n", uv_hubbed_system);
>>> ????? return 0;
>>> ? }
>>> ? ? static int __maybe_unused proc_hubless_show(struct seq_file *file, void *data)
>>> ? {
>>> +??? static int flag;
>>> +
>>> +??? proc_print_msg(&flag, "hubless", NULL);
>>> ????? seq_printf(file, "0x%x\n", uv_hubless_system);
>>> ????? return 0;
>>> ? }
>>> ? ? static int __maybe_unused proc_archtype_show(struct seq_file *file, void *data)
>>> ? {
>>> +??? static int flag;
>>> +
>>> +??? proc_print_msg(&flag, "archtype", NULL);
>>> ????? seq_printf(file, "%s/%s\n", uv_archtype, oem_table_id);
>>> ????? return 0;
>>> ? }
>>>
>>
>