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@@ -342,13 +1208,14 @@ void ufshpb_suspend(struct ufs_hba *hba)

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         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();

In blk_queue_enter(), BLK_MQ_REQ_NOWAIT flag can make error than wait 
rpm
resume. Please refer following code.

Oops, sorry, my memory needs to be refreshed on that part.

But will BLK_MQ_REQ_NOWAIT flag breaks your original purpose? When
runtime suspend is out of the picture, if traffic is heavy on the
request queue, map_work() will be stopped frequently once it is
not able to get a request from the queue - that shall pull down the
efficiency of one map_work(), that may hurt random performance...

I think deadlock prevention is the most important. So I want to add
BLK_MQ_REQ_NOWAIT flag.
Starvation of map request can be distinguish by return value of
blk_get_request(). -EWOULDBLOCK means there is no available tags for this
request. -EBUSY means failed on blk_queue_enter(). To overcome starvation
of map request, we can try N times in heavy traffic situation (maybe N=3?).

Thanks,
Daejun