Date: Wed, 16 Dec 2009 11:24:02 +0900 (JST)
Message-Id: <20091216.112402.226798335.d.hatayama@jp.fujitsu.com>
To: xiyou.wangcong@gmail.com
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, jdike@addtoit.com,
       tony.luck@intel.com, mhiramat@redhat.com
Subject: Re: [RFC, PATCH 4/4] elf_core_dump(): Add extended numbering
 support
From: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
In-Reply-To: <2375c9f90912150027h2435fad9yc35bc360f743d7a6@mail.gmail.com>
References: <20091215.114149.189724375.d.hatayama@jp.fujitsu.com>
	<2375c9f90912150027h2435fad9yc35bc360f743d7a6@mail.gmail.com>
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I agree with two of three cleanup ideas, but the last.

> > @@ -2079,11 +2139,19 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un
> > ? ? ? ?if (!elf_core_write_extra_data(file, &size, limit))
> > ? ? ? ? ? ? ? ?goto end_coredump;
> >
> > + ? ? ? if (e_phnum == PN_XNUM) {
> > + ? ? ? ? ? ? ? size += sizeof(*shdr4extnum);
> > + ? ? ? ? ? ? ? if (size > limit
> > + ? ? ? ? ? ? ? ? ? || !dump_write(file, shdr4extnum, sizeof(*shdr4extnum)))
> > + ? ? ? ? ? ? ? ? ? ? ? goto end_coredump;
> > + ? ? ? }
> > +
> > ?end_coredump:

There are two reasons I wrote like this.

First, the code like

if (size > limit || !dump_write(file, obj, sizeof(*obj)))
   goto end_coredump;

is used as the common idiom in thourghout elf_core_dump().  Not
writing goto only at the last use seems unnatural for me.

Second, there is a possibility that new writing operation for section
header table will be added. If the goto is removed now, the patch
writer must rewrite it again.

Thanks for your comments.
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