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Message-ID: <CAMuHMdXT63aJ2hXJg9mtMv-PZYT7CEw+ab-j42_VoFB-ib+ghg@mail.gmail.com>
Date: Fri, 15 Jan 2016 13:29:06 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Tejun Heo <tj@...nel.org>
Cc: "David S. Miller" <davem@...emloft.net>, pablo@...filter.org,
Patrick McHardy <kaber@...sh.net>, kadlec@...ckhole.kfki.hu,
Daniel Borkmann <daniel@...earbox.net>,
daniel.wagner@...-carit.de, nhorman@...driver.com,
Zefan Li <lizefan@...wei.com>,
Johannes Weiner <hannes@...xchg.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
netfilter-devel@...r.kernel.org, coreteam@...filter.org,
cgroups@...r.kernel.org,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
kernel-team@...com, ninasc@...com,
Josh Triplett <josh@...htriplett.org>
Subject: Re: [PATCH 2/8] kernfs: implement kernfs_walk_and_get()
On Mon, Dec 7, 2015 at 11:38 PM, Tejun Heo <tj@...nel.org> wrote:
> Implement kernfs_walk_and_get() which is similar to
> kernfs_find_and_get() but can walk a path instead of just a name.
>
> v2: Use strlcpy() instead of strlen() + memcpy() as suggested by
> David.
>
> Signed-off-by: Tejun Heo <tj@...nel.org>
> Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: David Miller <davem@...emloft.net>
> ---
> fs/kernfs/dir.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/kernfs.h | 12 ++++++++++++
> 2 files changed, 58 insertions(+)
>
> diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
> index 91e0045..742bf4a 100644
> --- a/fs/kernfs/dir.c
> +++ b/fs/kernfs/dir.c
> @@ -694,6 +694,29 @@ static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
> return NULL;
> }
>
> +static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
> + const unsigned char *path,
> + const void *ns)
> +{
> + static char path_buf[PATH_MAX]; /* protected by kernfs_mutex */
This is showing up in bloat-o-meter as increasing kernel size by 4 KiB.
> + size_t len = strlcpy(path_buf, path, PATH_MAX);
The full input string is copied because strsep() replaces the delimiters by
zeroes?
Can this be handled in some other way?
> + char *p = path_buf;
> + char *name;
> +
> + lockdep_assert_held(&kernfs_mutex);
> +
> + if (len >= PATH_MAX)
> + return NULL;
> +
> + while ((name = strsep(&p, "/")) && parent) {
> + if (*name == '\0')
> + continue;
> + parent = kernfs_find_ns(parent, name, ns);
> + }
> +
> + return parent;
> +}
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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