RE:(2) [PATCH] scsi: ufs: mark HPB support as BROKEN

[Daejun Park <daejun7.park@samsung.com>]

Hi Bart,

>On 10/26/21 11:27 AM, Martin K. Petersen wrote:
>>> Agreed, that was my initial proposed solution: get rid of the write
>>> buffer optimzation now to fix the API abuse and see if we can add it
>>> back in a more acceptable form later.
>> 
>> Doesn't matter to me whether we back out the 2.0 stuff or mark it as
>> broken. I merely objected to reverting all of HPB since I don't think
>> that would solve anything.
>> 
>> But obviously we'll need a patch to fix 5.15 ASAP...
> 
>I do not have access to a test setup that supports HPB.
> 
>If blk_insert_cloned_request() is moved into the device mapper then I
>think that blk_mq_request_issue_directly() will need to be exported. How
>about the (totally untested) patch below for removing the
>blk_insert_cloned_request() call from the UFS-HPB code?

I will test this code works on real device.

Thanks,
Daejun

> 
>Thanks,
> 
>Bart.
> 
> 
>---
>  block/blk-mq.c            | 1 +
>  block/blk-mq.h            | 1 -
>  drivers/scsi/ufs/ufshpb.c | 2 +-
>  include/linux/blkdev.h    | 1 +
>  4 files changed, 3 insertions(+), 2 deletions(-)
> 
>diff --git a/block/blk-mq.c b/block/blk-mq.c
>index 108a352051be..186321f450f6 100644
>--- a/block/blk-mq.c
>+++ b/block/blk-mq.c
>@@ -2084,6 +2084,7 @@ blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
> 
>          return ret;
>  }
>+EXPORT_SYMBOL_GPL(blk_mq_request_issue_directly);
> 
>  void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
>                  struct list_head *list)
>diff --git a/block/blk-mq.h b/block/blk-mq.h
>index d08779f77a26..ffba52189b18 100644
>--- a/block/blk-mq.h
>+++ b/block/blk-mq.h
>@@ -74,7 +74,6 @@ void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
>                                  struct list_head *list);
> 
>  /* Used by blk_insert_cloned_request() to issue request directly */
>-blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last);
>  void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
>                                      struct list_head *list);
> 
>diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
>index 66b19500844e..458eadcb604f 100644
>--- a/drivers/scsi/ufs/ufshpb.c
>+++ b/drivers/scsi/ufs/ufshpb.c
>@@ -547,7 +547,7 @@ static int ufshpb_execute_pre_req(struct ufshpb_lu *hpb, struct scsi_cmnd *cmd,
>                                   read_id);
>          rq->cmd_len = scsi_command_size(rq->cmd);
> 
>-        if (blk_insert_cloned_request(q, req) != BLK_STS_OK)
>+        if (blk_mq_request_issue_directly(req, true) != BLK_STS_OK)
>                  return -EAGAIN;
> 
>          hpb->stats.pre_req_cnt++;
>diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
>index 12b9dbcc980e..f203c7ea205b 100644
>--- a/include/linux/blkdev.h
>+++ b/include/linux/blkdev.h
>@@ -867,6 +867,7 @@ extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
>  extern void blk_rq_unprep_clone(struct request *rq);
>  extern blk_status_t blk_insert_cloned_request(struct request_queue *q,
>                                       struct request *rq);
>+blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last);
>  int blk_rq_append_bio(struct request *rq, struct bio *bio);
>  extern void blk_queue_split(struct bio **);
>  extern int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags);
> 
> 
>