[PATCH v4 16/29] ufs: core: Rework ufshcd_eh_device_reset_handler()

[Bart Van Assche <bvanassche@acm.org>]

Merge the MCQ mode and legacy mode loops into a single loop. This patch
prepares for optimizing the hot path by removing the direct hba->lrb[]
accesses from ufshcd_eh_device_reset_handler().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/ufs/core/ufshcd.c | 84 ++++++++++++++++++---------------------
 1 file changed, 38 insertions(+), 46 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 876c4de86b26..bdc6476694f3 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -7535,6 +7535,36 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
 	return err ? : result;
 }
 
+static bool ufshcd_clear_lu_cmds(struct request *req, void *priv)
+{
+	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+	struct scsi_device *sdev = cmd->device;
+	struct Scsi_Host *shost = sdev->host;
+	struct ufs_hba *hba = shost_priv(shost);
+	const u64 lun = *(u64 *)priv;
+	const u32 tag = req->tag;
+
+	if (sdev->lun != lun)
+		return true;
+
+	if (ufshcd_clear_cmd(hba, tag) < 0) {
+		dev_err(hba->dev, "%s: failed to clear request %d\n", __func__,
+			tag);
+		return true;
+	}
+
+	if (hba->mcq_enabled) {
+		struct ufs_hw_queue *hwq = ufshcd_mcq_req_to_hwq(hba, req);
+
+		if (hwq)
+			ufshcd_mcq_poll_cqe_lock(hba, hwq);
+		return true;
+	}
+
+	ufshcd_compl_one_cqe(hba, tag, NULL);
+	return true;
+}
+
 /**
  * ufshcd_eh_device_reset_handler() - Reset a single logical unit.
  * @cmd: SCSI command pointer
@@ -7543,12 +7573,8 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
  */
 static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
 {
-	unsigned long flags, pending_reqs = 0, not_cleared = 0;
 	struct Scsi_Host *host;
 	struct ufs_hba *hba;
-	struct ufs_hw_queue *hwq;
-	struct ufshcd_lrb *lrbp;
-	u32 pos, not_cleared_mask = 0;
 	int err;
 	u8 resp = 0xF, lun;
 
@@ -7557,50 +7583,16 @@ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
 
 	lun = ufshcd_scsi_to_upiu_lun(cmd->device->lun);
 	err = ufshcd_issue_tm_cmd(hba, lun, 0, UFS_LOGICAL_RESET, &resp);
-	if (err || resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-		if (!err)
-			err = resp;
-		goto out;
-	}
-
-	if (hba->mcq_enabled) {
-		for (pos = 0; pos < hba->nutrs; pos++) {
-			lrbp = &hba->lrb[pos];
-			if (ufshcd_cmd_inflight(lrbp->cmd) &&
-			    lrbp->lun == lun) {
-				ufshcd_clear_cmd(hba, pos);
-				hwq = ufshcd_mcq_req_to_hwq(hba, scsi_cmd_to_rq(lrbp->cmd));
-				ufshcd_mcq_poll_cqe_lock(hba, hwq);
-			}
-		}
-		err = 0;
-		goto out;
-	}
-
-	/* clear the commands that were pending for corresponding LUN */
-	spin_lock_irqsave(&hba->outstanding_lock, flags);
-	for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs)
-		if (hba->lrb[pos].lun == lun)
-			__set_bit(pos, &pending_reqs);
-	hba->outstanding_reqs &= ~pending_reqs;
-	spin_unlock_irqrestore(&hba->outstanding_lock, flags);
-
-	for_each_set_bit(pos, &pending_reqs, hba->nutrs) {
-		if (ufshcd_clear_cmd(hba, pos) < 0) {
-			spin_lock_irqsave(&hba->outstanding_lock, flags);
-			not_cleared = 1U << pos &
-				ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
-			hba->outstanding_reqs |= not_cleared;
-			not_cleared_mask |= not_cleared;
-			spin_unlock_irqrestore(&hba->outstanding_lock, flags);
-
-			dev_err(hba->dev, "%s: failed to clear request %d\n",
-				__func__, pos);
-		}
+	if (err) {
+	} else if (resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
+		err = resp;
+	} else {
+		/* clear the commands that were pending for corresponding LUN */
+		blk_mq_tagset_busy_iter(&hba->host->tag_set,
+					ufshcd_clear_lu_cmds,
+					&cmd->device->lun);
 	}
-	__ufshcd_transfer_req_compl(hba, pending_reqs & ~not_cleared_mask);
 
-out:
 	hba->req_abort_count = 0;
 	ufshcd_update_evt_hist(hba, UFS_EVT_DEV_RESET, (u32)err);
 	if (!err) {