On 28/01/2019 15:57, Christoph Hellwig wrote:

On Mon, Jan 28, 2019 at 03:36:58PM +0000, John Garry wrote:

quoted

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);

Your code is different to mine, then I see that this has been fixed in 
5.0-rc3:

commit 7809167da5c86fd6bf309b33dee7a797e263342f
Author: Ming Lei [off-list ref]
Date:   Wed Jan 16 19:08:15 2019 +0800

     block: don't lose track of REQ_INTEGRITY flag

     We need to pass bio->bi_opf after bio intergrity preparing, otherwise
     the flag of REQ_INTEGRITY may not be set on the allocated request, then
     breaks block integrity.

     Fixes: f9afca4d367b ("blk-mq: pass in request/bio flags to queue 
mapping")
     Cc: Hannes Reinecke [off-list ref]
     Cc: Keith Busch [off-list ref]
     Signed-off-by: Ming Lei [off-list ref]
     Signed-off-by: Jens Axboe [off-list ref]


Sorry for the noise,
John

.