From: Andrew Morton <akpm@linux-foundation.org>
To: Xi Wang <xi.wang@gmail.com>
Cc: linux-kernel@vger.kernel.org, Alex Elder <elder@dreamhost.com>,
David Airlie <airlied@linux.ie>,
Pekka Enberg <penberg@kernel.org>
Subject: Re: [RFC][PATCH] introduce SIZE_MAX
Date: Fri, 20 Apr 2012 16:03:37 -0700 [thread overview]
Message-ID: <20120420160337.479eeac0.akpm@linux-foundation.org> (raw)
In-Reply-To: <1334809671-15288-1-git-send-email-xi.wang@gmail.com>
On Thu, 19 Apr 2012 00:27:51 -0400
Xi Wang <xi.wang@gmail.com> wrote:
> ULONG_MAX is often used to check for integer overflow when calculating
> allocation size. While ULONG_MAX happens to work on most systems,
> there is no guarantee that `size_t' must be the same size as `long'.
>
> This patch introduces SIZE_MAX, the maximum value of `size_t', to
> improve portability and readability for allocation size validation.
>
> ...
>
> @@ -331,7 +331,7 @@ static int build_snap_context(struct ceph_snap_realm *realm)
>
> /* alloc new snap context */
> err = -ENOMEM;
> - if (num > (ULONG_MAX - sizeof(*snapc)) / sizeof(u64))
> + if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
> goto fail;
> snapc = kzalloc(sizeof(*snapc) + num*sizeof(u64), GFP_NOFS);
> if (!snapc)
hm, yes, I suppose that's better - hardwiring the assumption that
size_t has type unsigned long is pretty ugly.
Will we need something for ssize_t also?
next prev parent reply other threads:[~2012-04-20 23:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-19 4:27 [RFC][PATCH] introduce SIZE_MAX Xi Wang
2012-04-20 23:03 ` Andrew Morton [this message]
2012-04-21 2:59 ` Xi Wang
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