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SubjectRe: [PATCH] fs: O_* bit numbers uniqueness check
On Wed, Jan 06, 2010 at 03:07:01PM +0800, Eric Dumazet wrote:
> Le 06/01/2010 07:55, Wu Fengguang a écrit :
> > The O_* bit numbers are defined in 20+ arch/*, and hence can silently
> > overlap. Add a boot time check to ensure the uniqueness as suggested
> > by David Miller.
> >
> > 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 != 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));
> > +
>
> I cannot test it, but given O_RDONLY is 0, are you sure 20 bits are actually set ?

Yes, I tested it. The tricky one is O_SYNC, which actually has two bits..

Thanks,
Fengguang

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