Wu Fengguang <fengguang.wu@xxxxxxxxx> writes:
> 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@xxxxxxxxxxxxx>
>> > CC: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
>> > CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
>> > CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
>> > CC: Eric Paris <eparis@xxxxxxxxxx>
>> > Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
>> > ---
>> > {
>> > + /* 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..
What if a new architecture wants to use a single bit value (since it
does not need backwards compatibility)?
Andreas.
--
Andreas Schwab, schwab@xxxxxxxxxxxxxx
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