Re: bh->b_rdev==0 ??

H. Peter Anvin (hpa@transmeta.com)
20 Aug 1998 05:12:49 GMT

Followup to: <199808192337.TAA18894@blue.seas.upenn.edu>
By author: "Vladimir Dergachev" <vladimid@seas.upenn.edu>
In newsgroup: linux.dev.kernel
>
> Question:
>
> Is it true there are no devices with kdev_t number equal to 0 ?
>
> I am looking over contents of lru_list and there are a lot of
> buffer_head's with both b_rdev and b_rsector equal to 0.
>
> I tried using (bh->b_dev!=B_FREE) to test whether it contains
> some data but it doesn't work (probably bc B_FREE=0xffff).
>
> Or should I use (bh->b_count) instead ?
>

Device (0,0) is a non-device. It is the kdev_t equivalent of the null
pointer.

-hpa

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