[PATCH 3/3] block: Refuse adding appending a gapped integrity page to a bio

[Sagi Grimberg]

On 9/2/2015 10:18 PM, Jens Axboe wrote:
> On Wed, Sep 02 2015, Sagi Grimberg wrote:
>>> Does the below work for you?
>>
>> It's not on top of Keith virt_boundary patch right?
>> First glance looks ok though.
>
> Updated for that.
>

Thanks Jens,

I'll test it.

>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index b2625271a572..5f35a05337b1 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -436,9 +436,27 @@ no_merge:
>   	return 0;
>   }
>
> +static bool req_gap_to_prev(struct request *req, struct bio *next)
> +{
> +	struct bio *prev = req->biotail;
> +
> +	return bvec_gap_to_prev(req->q, &prev->bi_io_vec[prev->bi_vcnt - 1],
> +				next->bi_io_vec[0].bv_offset);
> +}
> +
> +static bool req_gap_to_next(struct request *req, struct bio *bio)
> +{
> +	struct bio *next = req->bio;
> +
> +	return bvec_gap_to_prev(req->q, &bio->bi_io_vec[bio->bi_vcnt - 1],
> +				next->bi_io_vec[0].bv_offset);
> +}
> +
>   int ll_back_merge_fn(struct request_queue *q, struct request *req,
>   		     struct bio *bio)
>   {
> +	if (bio_has_data(bio) && req_gap_to_prev(req, bio))
> +		return 0;
>   	if (blk_rq_sectors(req) + bio_sectors(bio) >
>   	    blk_rq_get_max_sectors(req)) {
>   		req->cmd_flags |= REQ_NOMERGE;
> @@ -457,6 +475,9 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
>   int ll_front_merge_fn(struct request_queue *q, struct request *req,
>   		      struct bio *bio)
>   {
> +
> +	if (bio_has_data(bio) && req_gap_to_next(req, bio))
> +		return 0;

I think it will be cleaner to git bio_has_data(bio) check into
req_gap_to_[prev|next]