Messages in this thread |  | | Date | Mon, 08 Feb 2021 16:34:33 +0800 | From | Can Guo <> | Subject | Re: [PATCH v19 2/3] scsi: ufs: L2P map management for HPB read |
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On 2021-02-08 16:03, Daejun Park wrote: >> @@ -342,13 +1208,14 @@ void ufshpb_suspend(struct ufs_hba *hba) >> > struct scsi_device *sdev; >> > >> > shost_for_each_device(sdev, hba->host) { >> > - hpb = sdev->hostdata; >> > + hpb = ufshpb_get_hpb_data(sdev); >> > if (!hpb) >> > continue; >> > >> > if (ufshpb_get_state(hpb) != HPB_PRESENT) >> > continue; >> > ufshpb_set_state(hpb, HPB_SUSPEND); >> > + ufshpb_cancel_jobs(hpb); >> >> Here may have a dead lock problem - in the case of runtime suspend, >> when ufshpb_suspend() is invoked, all of hba's children scsi devices >> are in RPM_SUSPENDED state. When this line tries to cancel a running >> map work, i.e. when ufshpb_get_map_req() calls below lines, it will >> be stuck at blk_queue_enter(). >> >> req = blk_get_request(hpb->sdev_ufs_lu->request_queue, >> REQ_OP_SCSI_IN, 0); >> >> Please check block layer power management, and see also commit >> d55d15a33 >> ("scsi: block: Do not accept any requests while suspended"). > > I am agree with your comment. > How about add BLK_MQ_REQ_NOWAIT flag on blk_get_request() to avoid > hang? >
That won't work - BLK_MQ_REQ_NOWAIT allows one to fast fail from blk_mq_get_tag(), but blk_queue_enter() comes before __blk_mq_alloc_request();
Regards,
Can Guo.
> Thanks, > Daejun
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