linux-kernel - Re: [PATCH 2/2] x86: modify show_shared_cpu_map in intel

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Message-ID: <36ca99e90803280201i708ce9b7y293a2c68e733f088@mail.gmail.com>
Date:	Fri, 28 Mar 2008 10:01:53 +0100
From:	"Bert Wesarg" <bert.wesarg@...glemail.com>
To:	"Mike Travis" <travis@....com>
Cc:	"Ingo Molnar" <mingo@...e.hu>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] x86: modify show_shared_cpu_map in intel_cacheinfo

On Fri, Mar 28, 2008 at 12:16 AM, Mike Travis <travis@....com> wrote:
> Used cpulist_scnprintf to print cpus on a leaf instead of requiring
>  a new "cpumask_scnprintf_len" function to determine the size of
>  the temporary buffer.  cpulist_scnprintf can be used to print directly
>  to the output buffer, eliminating the need for the temporary buffer.
>
>  Based on:
>         git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
>         git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git
>
>  Signed-off-by: Mike Travis <travis@....com>
>  ---
>   arch/x86/kernel/cpu/intel_cacheinfo.c |   25 +++++++++++++++++--------
>   1 file changed, 17 insertions(+), 8 deletions(-)
>
>  --- linux.trees.git.orig/arch/x86/kernel/cpu/intel_cacheinfo.c
>  +++ linux.trees.git/arch/x86/kernel/cpu/intel_cacheinfo.c
>  @@ -593,14 +593,23 @@ static ssize_t show_size(struct _cpuid4_
>
>   static ssize_t show_shared_cpu_map(struct _cpuid4_info *this_leaf, char *buf)
>   {
>  -       int n = 0;
>  -       int len = cpumask_scnprintf_len(nr_cpu_ids);
>  -       char *mask_str = kmalloc(len, GFP_KERNEL);
>  -
>  -       if (mask_str) {
>  -               cpumask_scnprintf(mask_str, len, this_leaf->shared_cpu_map);
>  -               n = sprintf(buf, "%s\n", mask_str);
>  -               kfree(mask_str);
>  +       /*
>  +        * cpulist_scnprintf() has the advantage of compressing
>  +        * consecutive cpu numbers into a single range which seems
>  +        * appropriate for cpus on a leaf.  This will change what is
>  +        * output so scripts that process the output will have to change.
So this breaks user space?

Bert
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