[Patch v4 03/12] memory-hotplug: remove redundant codes

[Tang Chen]

On 11/27/2012 06:00 PM, Wen Congyang wrote:
> offlining memory blocks and checking whether memory blocks are offlined
> are very similar. This patch introduces a new function to remove
> redundant codes.
>
> CC: David Rientjes<rientjes at google.com>
> CC: Jiang Liu<liuj97 at gmail.com>
> CC: Len Brown<len.brown at intel.com>
> CC: Christoph Lameter<cl at linux.com>
> Cc: Minchan Kim<minchan.kim at gmail.com>
> CC: Andrew Morton<akpm at linux-foundation.org>
> CC: KOSAKI Motohiro<kosaki.motohiro at jp.fujitsu.com>
> CC: Yasuaki Ishimatsu<isimatu.yasuaki at jp.fujitsu.com>
> Signed-off-by: Wen Congyang<wency at cn.fujitsu.com>

Can we merge this patch with [PATCH 03/12] ?

Reviewed-by: Tang Chen <tangchen at cn.fujitsu.com>

> ---
>   mm/memory_hotplug.c | 101 ++++++++++++++++++++++++++++------------------------
>   1 file changed, 55 insertions(+), 46 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index b6d1101..6d06488 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1005,20 +1005,14 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>   	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
>   }
>
> -int remove_memory(u64 start, u64 size)
> +static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
> +		void *arg, int (*func)(struct memory_block *, void *))
>   {
>   	struct memory_block *mem = NULL;
>   	struct mem_section *section;
> -	unsigned long start_pfn, end_pfn;
>   	unsigned long pfn, section_nr;
>   	int ret;
> -	int return_on_error = 0;
> -	int retry = 0;
> -
> -	start_pfn = PFN_DOWN(start);
> -	end_pfn = start_pfn + PFN_DOWN(size);
>
> -repeat:
>   	for (pfn = start_pfn; pfn<  end_pfn; pfn += PAGES_PER_SECTION) {
>   		section_nr = pfn_to_section_nr(pfn);
>   		if (!present_section_nr(section_nr))
> @@ -1035,22 +1029,61 @@ repeat:
>   		if (!mem)
>   			continue;
>
> -		ret = offline_memory_block(mem);
> +		ret = func(mem, arg);
>   		if (ret) {
> -			if (return_on_error) {
> -				kobject_put(&mem->dev.kobj);
> -				return ret;
> -			} else {
> -				retry = 1;
> -			}
> +			kobject_put(&mem->dev.kobj);
> +			return ret;
>   		}
>   	}
>
>   	if (mem)
>   		kobject_put(&mem->dev.kobj);
>
> -	if (retry) {
> -		return_on_error = 1;
> +	return 0;
> +}
> +
> +static int offline_memory_block_cb(struct memory_block *mem, void *arg)
> +{
> +	int *ret = arg;
> +	int error = offline_memory_block(mem);
> +
> +	if (error != 0&&  *ret == 0)
> +		*ret = error;
> +
> +	return 0;
> +}
> +
> +static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
> +{
> +	int ret = !is_memblock_offlined(mem);
> +
> +	if (unlikely(ret))
> +		pr_warn("removing memory fails, because memory "
> +			"[%#010llx-%#010llx] is onlined\n",
> +			PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
> +			PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);
> +
> +	return ret;
> +}
> +
> +int remove_memory(u64 start, u64 size)
> +{
> +	unsigned long start_pfn, end_pfn;
> +	int ret = 0;
> +	int retry = 1;
> +
> +	start_pfn = PFN_DOWN(start);
> +	end_pfn = start_pfn + PFN_DOWN(size);
> +
> +repeat:
> +	walk_memory_range(start_pfn, end_pfn,&ret,
> +			  offline_memory_block_cb);
> +	if (ret) {
> +		if (!retry)
> +			return ret;
> +
> +		retry = 0;
> +		ret = 0;
>   		goto repeat;
>   	}
>
> @@ -1068,37 +1101,13 @@ repeat:
>   	 * memory blocks are offlined.
>   	 */
>
> -	for (pfn = start_pfn; pfn<  end_pfn; pfn += PAGES_PER_SECTION) {
> -		section_nr = pfn_to_section_nr(pfn);
> -		if (!present_section_nr(section_nr))
> -			continue;
> -
> -		section = __nr_to_section(section_nr);
> -		/* same memblock? */
> -		if (mem)
> -			if ((section_nr>= mem->start_section_nr)&&
> -			    (section_nr<= mem->end_section_nr))
> -				continue;
> -
> -		mem = find_memory_block_hinted(section, mem);
> -		if (!mem)
> -			continue;
> -
> -		ret = is_memblock_offlined(mem);
> -		if (!ret) {
> -			pr_warn("removing memory fails, because memory "
> -				"[%#010llx-%#010llx] is onlined\n",
> -				PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
> -				PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1);
> -
> -			kobject_put(&mem->dev.kobj);
> -			unlock_memory_hotplug();
> -			return ret;
> -		}
> +	ret = walk_memory_range(start_pfn, end_pfn, NULL,
> +				is_memblock_offlined_cb);
> +	if (ret) {
> +		unlock_memory_hotplug();
> +		return ret;
>   	}
>
> -	if (mem)
> -		kobject_put(&mem->dev.kobj);
>   	unlock_memory_hotplug();
>
>   	return 0;