From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wu Fengguang <fengguang.wu@intel.com>
Subject: Re: [PATCH] fs: O_* bit numbers uniqueness check
Date: Sat, 9 Jan 2010 21:33:42 +0800
Message-ID: <20100109133342.GB20015@localhost>
References: <20100106065526.GB11368@localhost> <4B443695.5090301@gmail.com> <20100106072029.GA25169@localhost> <m2iqbfwq7h.fsf@whitebox.home>
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	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" <linux-fsdevel@vger.kernel.org>
To: Andreas Schwab <schwab@linux-m68k.org>
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On Wed, Jan 06, 2010 at 05:13:54PM +0800, Andreas Schwab wrote:
> Wu Fengguang <fengguang.wu@intel.com> writes:
>=20
> > On Wed, Jan 06, 2010 at 03:07:01PM +0800, Eric Dumazet wrote:
> >> Le 06/01/2010 07:55, Wu Fengguang a =C3=A9crit :
> >> > The O_* bit numbers are defined in 20+ arch/*, and hence can sil=
ently
> >> > overlap. Add a boot time check to ensure the uniqueness as sugge=
sted
> >> > by David Miller.
> >> >=20
> >> > CC: David Miller <davem@davemloft.net>
> >> > CC: Stephen Rothwell <sfr@canb.auug.org.au>
> >> > CC: Al Viro <viro@zeniv.linux.org.uk>
> >> > CC: Christoph Hellwig <hch@infradead.org>
> >> > CC: Eric Paris <eparis@redhat.com>
> >> > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> >> > ---
> >> >  {
> >> > +	/* please add new bits here to ensure allocation uniqueness */
> >> > +	BUG_ON(20 !=3D hweight32(
> >> > +		O_RDONLY	| O_WRONLY	| O_RDWR	|
> >> > +		O_CREAT		| O_EXCL	| O_NOCTTY	|
> >> > +		O_TRUNC		| O_APPEND	| O_NONBLOCK	|
> >> > +		O_SYNC		| FASYNC	| O_DIRECT	|
> >> > +		O_LARGEFILE	| O_DIRECTORY	| O_NOFOLLOW	|
> >> > +		O_NOATIME	| O_CLOEXEC	| O_RANDOM	|
> >> > +		FMODE_EXEC	| FMODE_NONOTIFY));
> >> > +
> >>=20
> >> I cannot test it, but given O_RDONLY is 0, are you sure 20 bits ar=
e actually set ?
> >
> > Yes, I tested it. The tricky one is O_SYNC, which actually has two =
bits..
>=20
> What if a new architecture wants to use a single bit value (since it
> does not need backwards compatibility)?

You mean to test __O_SYNC | O_DSYNC instead of O_SYNC?
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