scsi: ufs: ufshpb: Remove HPB2.0 flows

The Host Performance Buffer feature allows UFS read commands to carry the
physical media addresses along with the LBAs, thus allowing less internal
L2P-table switches in the device.  HPB1.0 allowed a single LBA, while
HPB2.0 increases this capacity up to 255 blocks.

Carrying more than a single record, the read operation is no longer purely
of type "read" but a "hybrid" command: Writing the physical address to the
device in one operation and reading back the required payload in another.

The JEDEC HPB spec defines two commands for this operation:
HPB-WRITE-BUFFER (0x2) to write the physical addresses to device, and
HPB-READ to read the payload.

With the current HPB design the UFS driver has no alternative but to divide
the READ request into 2 separate commands: HPB-WRITE-BUFFER and HPB-READ.
This causes a great deal of aggravation to the block layer guys who
demanded that we completely revert the entire HPB driver regardless of the
huge amount of corporate effort already invested in it.

As a compromise, remove only the pieces that implement the 2.0
specification. This is done as a matter of urgency for the final 5.15
release.

Link: https://lore.kernel.org/r/20211030062301.248-1-avri.altman@wdc.comTested-by: Avri Altman <avri.altman@wdc.com>
Tested-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Co-developed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -2737,12 +2737,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 
 	lrbp->req_abort_skip = false;
 
-	err = ufshpb_prep(hba, lrbp);
-	if (err == -EAGAIN) {
-		lrbp->cmd = NULL;
-		ufshcd_release(hba);
-		goto out;
-	}
+	ufshpb_prep(hba, lrbp);
 
 	ufshcd_comp_scsi_upiu(hba, lrbp);
 

drivers/scsi/ufs/ufshpb.c

@@ -84,16 +84,6 @@ static bool ufshpb_is_supported_chunk(struct ufshpb_lu *hpb, int transfer_len)
 	return transfer_len <= hpb->pre_req_max_tr_len;
 }
 
-/*
- * In this driver, WRITE_BUFFER CMD support 36KB (len=9) ~ 1MB (len=256) as
- * default. It is possible to change range of transfer_len through sysfs.
- */
-static inline bool ufshpb_is_required_wb(struct ufshpb_lu *hpb, int len)
-{
-	return len > hpb->pre_req_min_tr_len &&
-	       len <= hpb->pre_req_max_tr_len;
-}
-
 static bool ufshpb_is_general_lun(int lun)
 {
 	return lun < UFS_UPIU_MAX_UNIT_NUM_ID;
@@ -334,7 +324,7 @@ ufshpb_get_pos_from_lpn(struct ufshpb_lu *hpb, unsigned long lpn, int *rgn_idx,
 
 static void
 ufshpb_set_hpb_read_to_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp,
-			    __be64 ppn, u8 transfer_len, int read_id)
+			    __be64 ppn, u8 transfer_len)
 {
 	unsigned char *cdb = lrbp->cmd->cmnd;
 	__be64 ppn_tmp = ppn;
@@ -346,256 +336,11 @@ ufshpb_set_hpb_read_to_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp,
 	/* ppn value is stored as big-endian in the host memory */
 	memcpy(&cdb[6], &ppn_tmp, sizeof(__be64));
 	cdb[14] = transfer_len;
-	cdb[15] = read_id;
+	cdb[15] = 0;
 
 	lrbp->cmd->cmd_len = UFS_CDB_SIZE;
 }
 
-static inline void ufshpb_set_write_buf_cmd(unsigned char *cdb,
-					    unsigned long lpn, unsigned int len,
-					    int read_id)
-{
-	cdb[0] = UFSHPB_WRITE_BUFFER;
-	cdb[1] = UFSHPB_WRITE_BUFFER_PREFETCH_ID;
-
-	put_unaligned_be32(lpn, &cdb[2]);
-	cdb[6] = read_id;
-	put_unaligned_be16(len * HPB_ENTRY_SIZE, &cdb[7]);
-
-	cdb[9] = 0x00;	/* Control = 0x00 */
-}
-
-static struct ufshpb_req *ufshpb_get_pre_req(struct ufshpb_lu *hpb)
-{
-	struct ufshpb_req *pre_req;
-
-	if (hpb->num_inflight_pre_req >= hpb->throttle_pre_req) {
-		dev_info(&hpb->sdev_ufs_lu->sdev_dev,
-			 "pre_req throttle. inflight %d throttle %d",
-			 hpb->num_inflight_pre_req, hpb->throttle_pre_req);
-		return NULL;
-	}
-
-	pre_req = list_first_entry_or_null(&hpb->lh_pre_req_free,
-					   struct ufshpb_req, list_req);
-	if (!pre_req) {
-		dev_info(&hpb->sdev_ufs_lu->sdev_dev, "There is no pre_req");
-		return NULL;
-	}
-
-	list_del_init(&pre_req->list_req);
-	hpb->num_inflight_pre_req++;
-
-	return pre_req;
-}
-
-static inline void ufshpb_put_pre_req(struct ufshpb_lu *hpb,
-				      struct ufshpb_req *pre_req)
-{
-	pre_req->req = NULL;
-	bio_reset(pre_req->bio);
-	list_add_tail(&pre_req->list_req, &hpb->lh_pre_req_free);
-	hpb->num_inflight_pre_req--;
-}
-
-static void ufshpb_pre_req_compl_fn(struct request *req, blk_status_t error)
-{
-	struct ufshpb_req *pre_req = (struct ufshpb_req *)req->end_io_data;
-	struct ufshpb_lu *hpb = pre_req->hpb;
-	unsigned long flags;
-
-	if (error) {
-		struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
-		struct scsi_sense_hdr sshdr;
-
-		dev_err(&hpb->sdev_ufs_lu->sdev_dev, "block status %d", error);
-		scsi_command_normalize_sense(cmd, &sshdr);
-		dev_err(&hpb->sdev_ufs_lu->sdev_dev,
-			"code %x sense_key %x asc %x ascq %x",
-			sshdr.response_code,
-			sshdr.sense_key, sshdr.asc, sshdr.ascq);
-		dev_err(&hpb->sdev_ufs_lu->sdev_dev,
-			"byte4 %x byte5 %x byte6 %x additional_len %x",
-			sshdr.byte4, sshdr.byte5,
-			sshdr.byte6, sshdr.additional_length);
-	}
-
-	blk_mq_free_request(req);
-	spin_lock_irqsave(&hpb->rgn_state_lock, flags);
-	ufshpb_put_pre_req(pre_req->hpb, pre_req);
-	spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-}
-
-static int ufshpb_prep_entry(struct ufshpb_req *pre_req, struct page *page)
-{
-	struct ufshpb_lu *hpb = pre_req->hpb;
-	struct ufshpb_region *rgn;
-	struct ufshpb_subregion *srgn;
-	__be64 *addr;
-	int offset = 0;
-	int copied;
-	unsigned long lpn = pre_req->wb.lpn;
-	int rgn_idx, srgn_idx, srgn_offset;
-	unsigned long flags;
-
-	addr = page_address(page);
-	ufshpb_get_pos_from_lpn(hpb, lpn, &rgn_idx, &srgn_idx, &srgn_offset);
-
-	spin_lock_irqsave(&hpb->rgn_state_lock, flags);
-
-next_offset:
-	rgn = hpb->rgn_tbl + rgn_idx;
-	srgn = rgn->srgn_tbl + srgn_idx;
-
-	if (!ufshpb_is_valid_srgn(rgn, srgn))
-		goto mctx_error;
-
-	if (!srgn->mctx)
-		goto mctx_error;
-
-	copied = ufshpb_fill_ppn_from_page(hpb, srgn->mctx, srgn_offset,
-					   pre_req->wb.len - offset,
-					   &addr[offset]);
-
-	if (copied < 0)
-		goto mctx_error;
-
-	offset += copied;
-	srgn_offset += copied;
-
-	if (srgn_offset == hpb->entries_per_srgn) {
-		srgn_offset = 0;
-
-		if (++srgn_idx == hpb->srgns_per_rgn) {
-			srgn_idx = 0;
-			rgn_idx++;
-		}
-	}
-
-	if (offset < pre_req->wb.len)
-		goto next_offset;
-
-	spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-	return 0;
-mctx_error:
-	spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-	return -ENOMEM;
-}
-
-static int ufshpb_pre_req_add_bio_page(struct ufshpb_lu *hpb,
-				       struct request_queue *q,
-				       struct ufshpb_req *pre_req)
-{
-	struct page *page = pre_req->wb.m_page;
-	struct bio *bio = pre_req->bio;
-	int entries_bytes, ret;
-
-	if (!page)
-		return -ENOMEM;
-
-	if (ufshpb_prep_entry(pre_req, page))
-		return -ENOMEM;
-
-	entries_bytes = pre_req->wb.len * sizeof(__be64);
-
-	ret = bio_add_pc_page(q, bio, page, entries_bytes, 0);
-	if (ret != entries_bytes) {
-		dev_err(&hpb->sdev_ufs_lu->sdev_dev,
-			"bio_add_pc_page fail: %d", ret);
-		return -ENOMEM;
-	}
-	return 0;
-}
-
-static inline int ufshpb_get_read_id(struct ufshpb_lu *hpb)
-{
-	if (++hpb->cur_read_id >= MAX_HPB_READ_ID)
-		hpb->cur_read_id = 1;
-	return hpb->cur_read_id;
-}
-
-static int ufshpb_execute_pre_req(struct ufshpb_lu *hpb, struct scsi_cmnd *cmd,
-				  struct ufshpb_req *pre_req, int read_id)
-{
-	struct scsi_device *sdev = cmd->device;
-	struct request_queue *q = sdev->request_queue;
-	struct request *req;
-	struct scsi_request *rq;
-	struct bio *bio = pre_req->bio;
-
-	pre_req->hpb = hpb;
-	pre_req->wb.lpn = sectors_to_logical(cmd->device,
-					     blk_rq_pos(scsi_cmd_to_rq(cmd)));
-	pre_req->wb.len = sectors_to_logical(cmd->device,
-					     blk_rq_sectors(scsi_cmd_to_rq(cmd)));
-	if (ufshpb_pre_req_add_bio_page(hpb, q, pre_req))
-		return -ENOMEM;
-
-	req = pre_req->req;
-
-	/* 1. request setup */
-	blk_rq_append_bio(req, bio);
-	req->rq_disk = NULL;
-	req->end_io_data = (void *)pre_req;
-	req->end_io = ufshpb_pre_req_compl_fn;
-
-	/* 2. scsi_request setup */
-	rq = scsi_req(req);
-	rq->retries = 1;
-
-	ufshpb_set_write_buf_cmd(rq->cmd, pre_req->wb.lpn, pre_req->wb.len,
-				 read_id);
-	rq->cmd_len = scsi_command_size(rq->cmd);
-
-	if (blk_insert_cloned_request(q, req) != BLK_STS_OK)
-		return -EAGAIN;
-
-	hpb->stats.pre_req_cnt++;
-
-	return 0;
-}
-
-static int ufshpb_issue_pre_req(struct ufshpb_lu *hpb, struct scsi_cmnd *cmd,
-				int *read_id)
-{
-	struct ufshpb_req *pre_req;
-	struct request *req = NULL;
-	unsigned long flags;
-	int _read_id;
-	int ret = 0;
-
-	req = blk_get_request(cmd->device->request_queue,
-			      REQ_OP_DRV_OUT | REQ_SYNC, BLK_MQ_REQ_NOWAIT);
-	if (IS_ERR(req))
-		return -EAGAIN;
-
-	spin_lock_irqsave(&hpb->rgn_state_lock, flags);
-	pre_req = ufshpb_get_pre_req(hpb);
-	if (!pre_req) {
-		ret = -EAGAIN;
-		goto unlock_out;
-	}
-	_read_id = ufshpb_get_read_id(hpb);
-	spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-
-	pre_req->req = req;
-
-	ret = ufshpb_execute_pre_req(hpb, cmd, pre_req, _read_id);
-	if (ret)
-		goto free_pre_req;
-
-	*read_id = _read_id;
-
-	return ret;
-free_pre_req:
-	spin_lock_irqsave(&hpb->rgn_state_lock, flags);
-	ufshpb_put_pre_req(hpb, pre_req);
-unlock_out:
-	spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-	blk_put_request(req);
-	return ret;
-}
-
 /*
  * This function will set up HPB read command using host-side L2P map data.
  */
@@ -609,7 +354,6 @@ int ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 	__be64 ppn;
 	unsigned long flags;
 	int transfer_len, rgn_idx, srgn_idx, srgn_offset;
-	int read_id = 0;
 	int err = 0;
 
 	hpb = ufshpb_get_hpb_data(cmd->device);
@@ -685,24 +429,8 @@ int ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 		dev_err(hba->dev, "get ppn failed. err %d\n", err);
 		return err;
 	}
-	if (!ufshpb_is_legacy(hba) &&
-	    ufshpb_is_required_wb(hpb, transfer_len)) {
-		err = ufshpb_issue_pre_req(hpb, cmd, &read_id);
-		if (err) {
-			unsigned long timeout;
-
-			timeout = cmd->jiffies_at_alloc + msecs_to_jiffies(
-				  hpb->params.requeue_timeout_ms);
 
-			if (time_before(jiffies, timeout))
-				return -EAGAIN;
-
-			hpb->stats.miss_cnt++;
-			return 0;
-		}
-	}
-
-	ufshpb_set_hpb_read_to_upiu(hba, lrbp, ppn, transfer_len, read_id);
+	ufshpb_set_hpb_read_to_upiu(hba, lrbp, ppn, transfer_len);
 
 	hpb->stats.hit_cnt++;
 	return 0;
@@ -1841,16 +1569,11 @@ static void ufshpb_lu_parameter_init(struct ufs_hba *hba,
 	u32 entries_per_rgn;
 	u64 rgn_mem_size, tmp;
 
-	/* for pre_req */
-	hpb->pre_req_min_tr_len = hpb_dev_info->max_hpb_single_cmd + 1;
-
 	if (ufshpb_is_legacy(hba))
 		hpb->pre_req_max_tr_len = HPB_LEGACY_CHUNK_HIGH;
 	else
 		hpb->pre_req_max_tr_len = HPB_MULTI_CHUNK_HIGH;
 
-	hpb->cur_read_id = 0;
-
 	hpb->lu_pinned_start = hpb_lu_info->pinned_start;
 	hpb->lu_pinned_end = hpb_lu_info->num_pinned ?
 		(hpb_lu_info->pinned_start + hpb_lu_info->num_pinned - 1)

drivers/scsi/ufs/ufshpb.h

@@ -241,8 +241,6 @@ struct ufshpb_lu {
 	spinlock_t param_lock;
 
 	struct list_head lh_pre_req_free;
-	int cur_read_id;
-	int pre_req_min_tr_len;
 	int pre_req_max_tr_len;
 
 	/* cached L2P map management worker */