Re: [PATCH 2/3] blk-wbt: account any writing command as a write

[Christoph Hellwig]

On Thu, May 03, 2018 at 09:20:42AM -0600, Jens Axboe wrote:
> We currently special case WRITE and FLUSH, but we should really
> just include any command with the write bit set. This ensures
> that we account DISCARD.

Looks fine,

Reviewed-by: Christoph Hellwig <h...@lst.de>

> diff --git a/block/blk-wbt.c b/block/blk-wbt.c
> index f92fc84b5e2c..3e34b41bcefc 100644
> --- a/block/blk-wbt.c
> +++ b/block/blk-wbt.c
> @@ -701,7 +701,7 @@ static int wbt_data_dir(const struct request *rq)
>  
>       if (op == REQ_OP_READ)
>               return READ;
> -     else if (op == REQ_OP_WRITE || op == REQ_OP_FLUSH)
> +     else if (op_is_write(op))
>               return WRITE;
>  
>       /* don't account */

But this whole function smells, the return value is an array
index, so instead of abusing read/write this should return 0 or 1
and be called _idx or similar.  But I guess that is a question for the
higher level interface.