From: Roland Dreier <rdreier@cisco.com>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Miller <davem@davemloft.net>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Al Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
Eric Paris <eparis@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] fs: O_* bit numbers uniqueness check
Date: Tue, 05 Jan 2010 23:08:08 -0800 [thread overview]
Message-ID: <adahbqzvhgn.fsf@roland-alpha.cisco.com> (raw)
In-Reply-To: <20100106065526.GB11368@localhost> (Wu Fengguang's message of "Wed, 6 Jan 2010 14:55:26 +0800")
> + /* please add new bits here to ensure allocation uniqueness */
> + BUG_ON(20 != hweight32(
> + O_RDONLY | O_WRONLY | O_RDWR |
I wonder if there's a way to make this BUILD_BUG_ON(), so the problem is
caught at compile time (a change like adding an O_ flag is often compile
tested only for obscure archs). One could create a compile-time
macro-ized version of hweight32() and use that, I guess, although I'm
not sure it's worth the ugliness.
Failing that maybe this should be WARN_ON()? I'd be annoyed if my arch
wouldn't boot because some strange new O_ flag happened to collide.
- R.
next prev parent reply other threads:[~2010-01-06 7:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-06 6:55 Wu Fengguang
2010-01-06 7:07 ` Eric Dumazet
2010-01-06 7:20 ` Wu Fengguang
2010-01-06 9:13 ` Andreas Schwab
2010-01-09 13:33 ` Wu Fengguang
2010-01-06 7:08 ` Roland Dreier [this message]
2010-01-06 7:18 ` [PATCH v2] " Wu Fengguang
2010-01-06 7:30 ` Roland Dreier
2010-01-06 7:42 ` Wu Fengguang
2010-01-06 16:20 ` [PATCH] " Jamie Lokier
2010-01-09 13:44 ` Wu Fengguang
2010-01-06 15:48 ` Christoph Hellwig
2010-01-09 13:52 ` Wu Fengguang
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