linux-kernel - RE: [PATCH 06/13] proc: convert /proc/self to _print

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Message-ID: <54cb86c6d96b47bc8017a69be124c105@AcuMS.aculab.com>
Date:   Wed, 29 Aug 2018 09:50:50 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Alexey Dobriyan' <adobriyan@...il.com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 06/13] proc: convert /proc/self to _print_integer()

From: Alexey Dobriyan
> Sent: 28 August 2018 00:15
> ---
>  fs/proc/self.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/proc/self.c b/fs/proc/self.c
> index 127265e5c55f..b2279412237b 100644
> --- a/fs/proc/self.c
> +++ b/fs/proc/self.c
> @@ -14,6 +14,7 @@ static const char *proc_self_get_link(struct dentry *dentry,
>  {
>  	struct pid_namespace *ns = proc_pid_ns(inode);
>  	pid_t tgid = task_tgid_nr_ns(current, ns);
> +	char buf[10], *p = buf + sizeof(buf);
>  	char *name;
> 
>  	if (!tgid)
> @@ -22,7 +23,11 @@ static const char *proc_self_get_link(struct dentry *dentry,
>  	name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
>  	if (unlikely(!name))
>  		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
> -	sprintf(name, "%u", tgid);
> +

Best not to 'hide' the initialisation of 'p' at the top of the function.
Much easier to see what is going on if it is moved here.

> +	p = _print_integer_u32(p, tgid);

or just:
	p = _print_integer(buf + sizeof(buf), tgid);

(What a horrid interface ...)

> +	memcpy(name, p, buf + sizeof(buf) - p);
> +	name[buf + sizeof(buf) - p] = '\0';
> +
>  	set_delayed_call(done, kfree_link, name);
>  	return name;
>  }
> --
> 2.16.4

-
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