linux-kernel - Re: [PATCH 01/15] x86/e820: remove conditional early mapping in parse_e820

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Message-ID: <20101230083745.GC11721@angua.secretlab.ca>
Date:	Thu, 30 Dec 2010 01:37:45 -0700
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:	linux-kernel@...r.kernel.org, sodaville@...utronix.de,
	x86@...nel.org, dirk.brandewie@...il.com
Subject: Re: [PATCH 01/15] x86/e820: remove conditional early mapping in
 parse_e820_ext

On Fri, Dec 17, 2010 at 04:33:39PM +0100, Sebastian Andrzej Siewior wrote:
> This patch ensures that the memory passed from parse_setup_data() is
> large enough to cover the complete data structure. That means that the
> conditional mapping in parse_e820_ext() can go.
> 
> While here, I also attempt not to map two pages if the address is not
> aligned to a page boundary.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> Signed-off-by: Dirk Brandewie <dirk.brandewie@...il.com>
> ---

I assume this patch is a prereq for the rest of the series.  Should I
merge it via the devicetree tree when I pick up the other patches?

It looks okay to me.  One comment below, but not one that would prevent
picking up this patch.

g.

>  arch/x86/include/asm/e820.h |    2 +-
>  arch/x86/kernel/e820.c      |    8 +-------
>  arch/x86/kernel/setup.c     |   20 +++++++++++++++++---
>  3 files changed, 19 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h
> index 5be1542..e956492 100644
> --- a/arch/x86/include/asm/e820.h
> +++ b/arch/x86/include/asm/e820.h
> @@ -93,7 +93,7 @@ extern void e820_setup_gap(void);
>  extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
>  			unsigned long start_addr, unsigned long long end_addr);
>  struct setup_data;
> -extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data);
> +extern void parse_e820_ext(struct setup_data *data);
>  
>  #if defined(CONFIG_X86_64) || \
>  	(defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 0c2b7ef..33f6361 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -666,21 +666,15 @@ __init void e820_setup_gap(void)
>   * boot_params.e820_map, others are passed via SETUP_E820_EXT node of
>   * linked list of struct setup_data, which is parsed here.
>   */
> -void __init parse_e820_ext(struct setup_data *sdata, unsigned long pa_data)
> +void __init parse_e820_ext(struct setup_data *sdata)
>  {
> -	u32 map_len;
>  	int entries;
>  	struct e820entry *extmap;
>  
>  	entries = sdata->len / sizeof(struct e820entry);
> -	map_len = sdata->len + sizeof(struct setup_data);
> -	if (map_len > PAGE_SIZE)
> -		sdata = early_ioremap(pa_data, map_len);
>  	extmap = (struct e820entry *)(sdata->data);
>  	__append_e820_map(extmap, entries);
>  	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
> -	if (map_len > PAGE_SIZE)
> -		early_iounmap(sdata, map_len);
>  	printk(KERN_INFO "extended physical RAM map:\n");
>  	e820_print_map("extended");
>  }
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 0afb8c7..577d06b 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -429,16 +429,30 @@ static void __init parse_setup_data(void)
>  		return;
>  	pa_data = boot_params.hdr.setup_data;
>  	while (pa_data) {
> -		data = early_memremap(pa_data, PAGE_SIZE);
> +		u32 data_len;
> +		u32 map_len;
> +
> +		map_len = max(PAGE_SIZE - (pa_data & ~PAGE_MASK),
> +				(u64)sizeof(struct setup_data));
> +		data = early_memremap(pa_data, map_len);
> +		data_len = data->len + sizeof(struct setup_data);
> +		if (data_len > map_len) {
> +			early_iounmap(data, map_len);
> +			data = early_memremap(pa_data, data_len);

if you add
+			map_len = data_len;
then...

> +		}
> +
>  		switch (data->type) {
>  		case SETUP_E820_EXT:
> -			parse_e820_ext(data, pa_data);
> +			parse_e820_ext(data);
>  			break;
>  		default:
>  			break;
>  		}
>  		pa_data = data->next;
> -		early_iounmap(data, PAGE_SIZE);
> +		if (data_len > map_len)
> +			early_iounmap(data, data_len);
> +		else
> +			early_iounmap(data, map_len);

...this can be simplified to:

-		early_iounmap(data, PAGE_SIZE);
+		early_iounmap(data, map_len);

>  	}
>  }
>  
> -- 
> 1.7.3.2
> 
> --
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