On Wed, Oct 27, 2021 at 10:01:42AM -0700, Bart Van Assche wrote: > On 10/27/21 9:16 AM, Martin K. Petersen wrote: > > Given that HPB developed over time, I am not sure how simple a revert > > would be. And we only have a couple of days left before release. I > > really want the smallest patch possible that either removes or disables > > the 2.0 support. > > How about one of the untested patches below? > > The patch below disables support for HPB 2.0 by ignoring the HPB version reported > by the UFS controller: > > diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c > index 66b19500844e..5f9f7139480a 100644 > --- a/drivers/scsi/ufs/ufshpb.c > +++ b/drivers/scsi/ufs/ufshpb.c > @@ -2872,8 +2872,8 @@ void ufshpb_get_dev_info(struct ufs_hba *hba, u8 *desc_buf) > return; > } > > - if (version == HPB_SUPPORT_LEGACY_VERSION) > - hpb_dev_info->is_legacy = true; > + /* Do not use HPB 2.0 because of the blk_insert_cloned_request() call. */ > + hpb_dev_info->is_legacy = true; I guess you may change ufshpb_is_required_wb() to return false simply with comment. > > ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR, > QUERY_ATTR_IDN_MAX_HPB_SINGLE_CMD, 0, 0, &max_hpb_single_cmd); > > > The second patch changes the blk_insert_cloned_request() call into a > blk_execute_rq_nowait() call. That should work fine since this function > bypasses the I/O scheduler for passthrough requests: Either ->is_legacy is set as true or ufshpb_is_required_wb() returns false, blk_insert_cloned_request() won't be called. But here blk_execute_rq_nowait() should be used since it is one driver private IO. That also shows the private command of pre_req is run concurrently with the original FS IO, and two tags are consumed for doing one IO. It could be done one by one, but I guess it is a bit slower, just saw Daejun replied this point. thanks, Ming
