Re: [PATCH] virtio_blk: use a wrapper function to access io context information of IO requests

[Jens Axboe <jens.axboe@oracle.com>]

On Thu, Aug 14 2008, Fernando Luis Vázquez Cao wrote:
> struct request has an ioprio member but it is never updated because
> currently bios do not hold io context information. The implication of
> this is that virtio_blk ends up passing useless information to the
> backend driver.
> 
> That said, some IO schedulers such as CFQ do store io context
> information in struct request, but use private members for that, which
> means that that information cannot be directly accessed in a IO
> scheduler-independent way.
> 
> This patch adds a function to obtain the ioprio of a request. We should
> avoid accessing ioprio directly and use this function instead, so that
> its users do not have to care about future changes in block layer
> structures or what the currently active IO controller is.
> 
> This patch does not introduce any functional changes but paves the way
> for future clean-ups and enhancements.
> 
> Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> Acked-by: Rusty Russell <rusty@rustcorp.com.au>

Fine with me, applied.

-- 
Jens Axboe