On Fri, 3 Mar 2000, Tigran Aivazian wrote:
> if (atomic_read(&buf->b_count)) {
> atomic_dec(&buf->b_count);
> return;
> }
>
>suggests that when the same buffer is brelse'd on two CPUs they both could
>get b_count=1 and decrement it thus causing negative b_count. I suppose I
>could write a tiny module creating two kernel_thread() which simply
>bread()/brelse() the same block from the same device in a reasonably busy
>loop to cause negative b_count. Btw, while we are on this subject, is it
That's not possible because if you are calling brelse b_count can only be
major than zero in all cases.
The check is useless and it's there to catch wrongly double releases.
>legal to create two instances of the "same" kernel thread, i.e. pass the
>same address as 'fn' parameter and internally distinguish the threads by
>current->pid?
Yes.
Andrea
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