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SubjectRe: Linux Buffer Cache Does Not Support Mirroring
Jeff,

BTW, the RAID code is also using the async b_end_io callback, to
get a success/failure report on each I/O transaction. Cross
reference raid5_end_request() in raid5.c and raid1_end_request()
in raid1.c, which are installed as b_end_io callbacks in the
buffers which go to the real block drivers. In the RAID-5 case,
the callback function (called at the interrupt context) then wakes
up a kernel thread for further processing.

Gadi

On Tue, 2 Nov 1999, Jeff V. Merkey wrote:

>
> Alan,
>
> I'll try this.
>
> Jeff
>
> Alan Cox wrote:
> >
> > > I looked at the brw_page code. While everyone calls this an "async"
> > > interface, in fact, it uses the same semantic as a sync interface and
> > > does not allow support for callbacks.
> >
> > Its a function pointer. What else do you need other than passing a parameter
> > void * or similar to get more flexibility.
> >
> > You can use the callback to wake a thread, you can schedule a task after
> > IRQ completion, you can do stuff directly on the IRQ callback if you are
> > careful about deadlocks.
> >
> > -
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>
> -
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>


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