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From: Jan Beulich <jbeulich@suse.com>
To: Julien Grall <julien@xen.org>
Cc: xen-devel@lists.xenproject.org, alex.bennee@linaro.org,
	masami.hiramatsu@linaro.org, ehem+xen@m5p.com,
	bertrand.marquis@arm.com, andre.przywara@arm.com,
	"Julien Grall" <jgrall@amazon.com>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Ian Jackson" <iwj@xenproject.org>, "Wei Liu" <wl@xen.org>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 1/4] xen/acpi: Rework acpi_os_map_memory() and acpi_os_unmap_memory()
Date: Mon, 28 Sep 2020 12:09:24 +0200
Message-ID: <a07b59a0-41a3-ee4e-f28a-38499a2a4055@suse.com> (raw)
In-Reply-To: <b5624bfa-f24b-4c0a-6735-3473892fbd2f@xen.org>

On 28.09.2020 11:58, Julien Grall wrote:
> On 28/09/2020 09:18, Jan Beulich wrote:
>> On 26.09.2020 22:55, Julien Grall wrote:
>>> --- a/xen/arch/x86/acpi/lib.c
>>> +++ b/xen/arch/x86/acpi/lib.c
>>> @@ -46,6 +46,10 @@ char *__acpi_map_table(paddr_t phys, unsigned long size)
>>>   	if ((phys + size) <= (1 * 1024 * 1024))
>>>   		return __va(phys);
>>>   
>>> +	/* No arch specific implementation after early boot */
>>> +	if (system_state >= SYS_STATE_boot)
>>> +		return NULL;
>>
>> Considering the code in context above, the comment isn't entirely
>> correct.
> 
> How about "No arch specific implementation after early boot but for the 
> first 1MB"?

That or simply "No further ...".

>>> +{
>>> +	unsigned long vaddr = (unsigned long)ptr;
>>> +
>>> +	if (vaddr >= DIRECTMAP_VIRT_START &&
>>> +	    vaddr < DIRECTMAP_VIRT_END) {
>>> +		ASSERT(!((__pa(ptr) + size - 1) >> 20));
>>> +		return true;
>>> +	}
>>> +
>>> +	return (vaddr >= __fix_to_virt(FIX_ACPI_END)) &&
>>> +		(vaddr < (__fix_to_virt(FIX_ACPI_BEGIN) + PAGE_SIZE));
>>
>> Indentation is slightly wrong here.
> 
> This is Linux coding style and therefore is using hard tab. Care to 
> explain the problem?

The two opening parentheses should align with one another,
shouldn't they?

>>> +	ptr = __vmap(&mfn, PFN_UP(offs + size), 1, 1,
>>> +		     ACPI_MAP_MEM_ATTR, VMAP_DEFAULT);
>>> +
>>> +	return !ptr ? NULL : (ptr + offs);
>>
>> Slightly odd that you don't let the success case go first,
> 
> I don't really see the problem. Are you nitpicking?
> 
>> the more that it's minimally shorter:
>>
>> 	return ptr ? ptr + offs : NULL;

Well, I said "slightly odd" as sort of a replacement of "Nit:".
But I really think it would be more logical the other way
around, not so much for how it looks like, but to aid the not
uncommon compiler heuristics of assuming the "true" path is
the common one.

Jan


  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-26 20:55 [PATCH 0/4] xen/arm: Unbreak ACPI Julien Grall
2020-09-26 20:55 ` [PATCH 1/4] xen/acpi: Rework acpi_os_map_memory() and acpi_os_unmap_memory() Julien Grall
2020-09-28  8:18   ` Jan Beulich
2020-09-28  9:58     ` Julien Grall
2020-09-28 10:09       ` Jan Beulich [this message]
2020-09-28 10:39         ` Julien Grall
2020-10-10  9:49           ` Julien Grall
2020-10-10 10:04             ` Julien Grall
2020-09-29 11:10   ` Rahul Singh
2020-10-01  0:06   ` Stefano Stabellini
2020-10-01 15:09     ` Julien Grall
2020-09-26 20:55 ` [PATCH 2/4] xen/arm: acpi: The fixmap area should always be cleared during failure/unmap Julien Grall
2020-09-29 11:13   ` Rahul Singh
2020-10-01  0:30   ` Stefano Stabellini
2020-10-01 15:14     ` Julien Grall
2020-09-26 20:55 ` [PATCH 3/4] xen/arm: Check if the platform is not using ACPI before initializing Dom0less Julien Grall
2020-09-29 11:17   ` Rahul Singh
2020-09-30 23:26   ` Stefano Stabellini
2020-09-26 20:55 ` [PATCH 4/4] xen/arm: Introduce fw_unreserved_regions() and use it Julien Grall
2020-09-30 23:40   ` Stefano Stabellini
2020-10-01 15:34     ` Julien Grall
2020-09-27  1:47 ` [PATCH 0/4] xen/arm: Unbreak ACPI Elliott Mitchell
2020-09-29 15:28   ` Elliott Mitchell
2020-09-28  6:47 ` Masami Hiramatsu
2020-09-28 13:00   ` Masami Hiramatsu
2020-10-16 22:33     ` Xen-ARM EFI/ACPI problems (was: Re: [PATCH 0/4] xen/arm: Unbreak ACPI) Elliott Mitchell
2020-10-17  5:12       ` Elliott Mitchell
2020-10-08 18:39   ` [PATCH 0/4] xen/arm: Unbreak ACPI Elliott Mitchell
2020-10-09  9:39     ` Julien Grall
2020-10-09 14:22       ` Elliott Mitchell
2020-10-09 18:15         ` Julien Grall
2020-10-09 22:36           ` Elliott Mitchell
2020-10-09 21:49   ` Elliott Mitchell
2020-10-10 11:02   ` Julien Grall
2020-10-12 19:02     ` Stefano Stabellini
2020-10-12 21:34       ` Elliott Mitchell
2020-10-14  1:06         ` Stefano Stabellini
2020-10-14  1:37           ` Elliott Mitchell
2020-10-14 17:47             ` Julien Grall
2020-10-15 18:00               ` Stefano Stabellini
2020-10-14 17:44       ` Julien Grall
2020-09-29 11:10 ` Rahul Singh
2020-09-29 15:29 ` Alex Bennée
2020-09-29 17:07   ` Julien Grall
2020-09-29 21:11     ` Alex Bennée
2020-09-29 23:39       ` André Przywara
2020-09-30  8:51         ` Alex Bennée
2020-09-30 10:35         ` Julien Grall
2020-09-30  9:42       ` Julien Grall
2020-09-30 10:38         ` Alex Bennée
2020-09-30 11:10           ` Julien Grall

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