[PATCH v5 02/31] powerpc/fadump: move internal code to a new file

[Hari Bathini]

On 03/09/19 4:39 PM, Michael Ellerman wrote:
> Hari Bathini <hbathini at linux.ibm.com> writes:
>> Make way for refactoring platform specific FADump code by moving code
>> that could be referenced from multiple places to fadump-common.c file.
>>
>> Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
>> ---
>>  arch/powerpc/kernel/Makefile        |    2 
>>  arch/powerpc/kernel/fadump-common.c |  140 ++++++++++++++++++++++++++++++++++
>>  arch/powerpc/kernel/fadump-common.h |    8 ++
>>  arch/powerpc/kernel/fadump.c        |  146 ++---------------------------------
>>  4 files changed, 158 insertions(+), 138 deletions(-)
>>  create mode 100644 arch/powerpc/kernel/fadump-common.c
> 
> I don't understand why we need fadump.c and fadump-common.c? They're
> both common/shared across pseries & powernv aren't they?

The convention I tried to follow to have fadump-common.c shared between fadump.c,
pseries & powernv code while pseries & powernv code take callback requests from
fadump.c and use fadump-common.c (shared by both platforms), if necessary to fullfil
those requests...

> By the end of the series we end up with 149 lines in fadump-common.c
> which seems like a waste of time. Just put it all in fadump.c.

Yeah. Probably not worth a new C file. Will just have two separate headers. One for
internal code and one for interfacing with other modules...

[...]

>> + * Copyright 2019, IBM Corp.
>> + * Author: Hari Bathini <hbathini at linux.ibm.com>
> 
> These can just be:
> 
>  * Copyright 2011, Mahesh Salgaonkar, IBM Corporation.
>  * Copyright 2019, Hari Bathini, IBM Corporation.
> 

Sure.

>> + */
>> +
>> +#undef DEBUG
> 
> Don't undef DEBUG please.
> 

Sorry! Seeing such thing in most files, I thought this was the convention. Will drop
this change in all the new files I added.

>> +#define pr_fmt(fmt) "fadump: " fmt
>> +
>> +#include <linux/memblock.h>
>> +#include <linux/elf.h>
>> +#include <linux/mm.h>
>> +#include <linux/crash_core.h>
>> +
>> +#include "fadump-common.h"
>> +
>> +void *fadump_cpu_notes_buf_alloc(unsigned long size)
>> +{
>> +	void *vaddr;
>> +	struct page *page;
>> +	unsigned long order, count, i;
>> +
>> +	order = get_order(size);
>> +	vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
>> +	if (!vaddr)
>> +		return NULL;
>> +
>> +	count = 1 << order;
>> +	page = virt_to_page(vaddr);
>> +	for (i = 0; i < count; i++)
>> +		SetPageReserved(page + i);
>> +	return vaddr;
>> +}
> 
> I realise you're just moving this code, but why do we need all this hand
> rolled allocation stuff?

Yeah, I think alloc_pages_exact() may be better here. Mahesh, am I missing something?

- Hari