| Message ID | 1548337430-66690-1-git-send-email-chenxiang66@hisilicon.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | block: set rq->cmd_flags with bio->opf instead of data->cmd_flags when bio is not Null | expand |
+cc Jens + linux-block 在 2019/1/24 21:43, chenxiang 写道: > In function blk_mq_make_request(), though data->cmd_flags will be > initialized with bio->opf, later bio->opf may be set as REQ_INTEGRITY > if enabled DIX. So need to use bio->opf instead of data->cmd_flags in > function blk_mq_rq_ctx_init(), or flags REQ_INTEGRITY will not be set > 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. > > Fixes: f9afca4d367b ("blk-mq: pass in request/bio flags to queue mapping") > > Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> > Reviewed-by: John Garry <john.garry@huawei.com> > --- > block/blk-mq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 3ba37b9..c4a1c63 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -394,7 +394,7 @@ static struct request *blk_mq_get_request(struct request_queue *q, > return NULL; > } > > - rq = blk_mq_rq_ctx_init(data, tag, data->cmd_flags); > + rq = blk_mq_rq_ctx_init(data, tag, bio ? bio->bi_opf : data->cmd_flags); > if (!op_is_flush(data->cmd_flags)) { > rq->elv.icq = NULL; > if (e && e->type->ops.prepare_request) {
> > 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.
On 28/01/2019 14:07, Christoph Hellwig wrote: >>> 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 > > . >
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);
On 28/01/2019 15:57, Christoph Hellwig wrote: > 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); > > Your code is different to mine, then I see that this has been fixed in 5.0-rc3: commit 7809167da5c86fd6bf309b33dee7a797e263342f Author: Ming Lei <ming.lei@redhat.com> 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 <hare@suse.com> Cc: Keith Busch <keith.busch@intel.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Sorry for the noise, John > . >
在 2019/1/28 23:57, Christoph Hellwig 写道: > 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); Sorry to disturb, i used kernel 5.0-rc1 which has the issue, and it is fixed on linux-next branch. > > > . >
diff --git a/block/blk-mq.c b/block/blk-mq.c index 3ba37b9..c4a1c63 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -394,7 +394,7 @@ static struct request *blk_mq_get_request(struct request_queue *q, return NULL; } - rq = blk_mq_rq_ctx_init(data, tag, data->cmd_flags); + rq = blk_mq_rq_ctx_init(data, tag, bio ? bio->bi_opf : data->cmd_flags); if (!op_is_flush(data->cmd_flags)) { rq->elv.icq = NULL; if (e && e->type->ops.prepare_request) {
In function blk_mq_make_request(), though data->cmd_flags will be initialized with bio->opf, later bio->opf may be set as REQ_INTEGRITY if enabled DIX. So need to use bio->opf instead of data->cmd_flags in function blk_mq_rq_ctx_init(), or flags REQ_INTEGRITY will not be set 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. Fixes: f9afca4d367b ("blk-mq: pass in request/bio flags to queue mapping") Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> Reviewed-by: John Garry <john.garry@huawei.com> --- block/blk-mq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)