Re: [PATCH] fs: O_* bit numbers uniqueness check

From: Eric Dumazet
Date: Wed Jan 06 2010 - 02:17:19 EST


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 ?
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