Re: [PATCH] block: set rq->cmd_flags with bio->opf instead of data->cmd_flags when bio is not Null

[Christoph Hellwig]

On Mon, Jan 28, 2019 at 03:36:58PM +0000, John Garry wrote:
> As I understood, the problem is the scenario of calling
> blk_mq_make_request()->bio_integrity_prep() where we then allocate a bio
> integrity payload in calling bio_integrity_alloc().
> 
> In this case, bio_integrity_alloc() sets bio->bi_opf |= REQ_INTEGRITY, which
> is no longer consistent with data.cmd_flags.

I don't see how that could happen:

static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
{
	...

	if (!bio_integrity_prep(bio))
		return BLK_QC_T_NONE;

	...

	data.cmd_flags = bio->bi_opf;
        rq = blk_mq_get_request(q, bio, &data);