On 28/01/2019 14:07, Christoph Hellwig wrote:

quoted

quoted

for rq->cmd_flags. It will cause dix=0 in function
sd_setup_read_write_cmnd() when enabled DIX, which will cause IO
exception when enabled DIX.

For some IOs such as internal IO from SCSI layer, the parameter bio of
function blk_mq_get_request() is Null, so need to check bio to
decise rq->cmd_flags.

We have data->cmd_flags to deal with the NULL bio case.
blk_mq_make_request initializes data->cmd_flags from bio->bi_opf
just before calling blk_mq_get_request, so I'm really missing what you
are trying to fix here.

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.

John

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