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From: yan yan <clouds.yan@gmail.com>
To: Ryan Mallon <rmallon@gmail.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] proc: use kzalloc instead of kmalloc and memset
Date: Tue, 4 Sep 2012 17:10:40 +0800	[thread overview]
Message-ID: <CAH+=+MEuVqZhXMELQ=Faewg=4MU2VQr1X1Qq8QCyAu=E-qSeLQ@mail.gmail.com> (raw)
In-Reply-To: <50454EDC.7050101@gmail.com>

2012/9/4 Ryan Mallon <rmallon@gmail.com>
>
> On 04/09/12 00:14, yan wrote:
> > Signed-off-by: yan <clouds.yan@gmail.com>
> > ---
> >  fs/proc/generic.c |    3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/fs/proc/generic.c b/fs/proc/generic.c
> > index 9e8f631..38de015 100644
> > --- a/fs/proc/generic.c
> > +++ b/fs/proc/generic.c
> > @@ -616,10 +616,9 @@ static struct proc_dir_entry *__proc_create(struct
> > proc_dir_entry **parent,
> >
> >       len = strlen(fn);
> >
> > -     ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1,
> > GFP_KERNEL);
> > +     ent = kzalloc(sizeof(struct proc_dir_entry) + len + 1,
> > GFP_KERNEL);
> >       if (!ent) goto out;
> >
> > -     memset(ent, 0, sizeof(struct proc_dir_entry));
> >       memcpy(ent->name, fn, len + 1);
> >       ent->namelen = len;
> >       ent->mode = mode;
>
> Note that this change results in slightly different behaviour. Before
> your change only sizeof(struct proc_dir_entry) is zero'ed by memset, and
> then the name is filled in (the len + 1 part). After your change the
> structure and the name field are both zeroed, so the name field is being
> written to twice. The cost is probably negligible though.

Oh, I didn't notice that actually. Thank you.

      reply	other threads:[~2012-09-04  9:10 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-03 14:14 [PATCH 0/3] Trivial code clean for procfs yan
2012-09-03 14:14 ` [PATCH 1/3] proc: return -ENOMEM when inode allocation failed yan
2012-09-04  0:38   ` Ryan Mallon
2012-09-04  3:02   ` Cong Wang
2012-09-04  9:22     ` yan yan
2012-09-04 22:41       ` Andrew Morton
2012-09-05  7:15       ` Cong Wang
2012-09-05  7:57         ` yan yan
2012-09-03 14:14 ` [PATCH 2/3] proc : no need to initialize proc_inode->fd in proc_get_inode yan
2012-09-04 22:49   ` Andrew Morton
2012-09-03 14:14 ` [PATCH 3/3] proc: use kzalloc instead of kmalloc and memset yan
2012-09-04  0:44   ` Ryan Mallon
2012-09-04  9:10     ` yan yan [this message]

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