scsi: ufs: core: Clean up ufshcd_slave_alloc()

Combine ufshcd_get_lu_power_on_wp_status() and ufshcd_set_queue_depth()
into one single ufshcd_lu_init(), so that we only need to read the LUN
descriptor once.
Signed-off-by: Bean Huo <beanhuo@micron.com>
Link: https://lore.kernel.org/r/20221025222430.277768-3-beanhuo@iokpp.deReviewed-by: Arthur Simchaev <arthur.simchaev@wdc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/core/ufshcd.c

@@ -4861,100 +4861,6 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
 	return err;
 }
 
-/**
- * ufshcd_set_queue_depth - set lun queue depth
- * @sdev: pointer to SCSI device
- *
- * Read bLUQueueDepth value and activate scsi tagged command
- * queueing. For WLUN, queue depth is set to 1. For best-effort
- * cases (bLUQueueDepth = 0) the queue depth is set to a maximum
- * value that host can queue.
- */
-static void ufshcd_set_queue_depth(struct scsi_device *sdev)
-{
-	int ret = 0;
-	u8 lun_qdepth;
-	struct ufs_hba *hba;
-
-	hba = shost_priv(sdev->host);
-
-	lun_qdepth = hba->nutrs;
-	ret = ufshcd_read_unit_desc_param(hba,
-					  ufshcd_scsi_to_upiu_lun(sdev->lun),
-					  UNIT_DESC_PARAM_LU_Q_DEPTH,
-					  &lun_qdepth,
-					  sizeof(lun_qdepth));
-
-	/* Some WLUN doesn't support unit descriptor */
-	if (ret == -EOPNOTSUPP)
-		lun_qdepth = 1;
-	else if (!lun_qdepth)
-		/* eventually, we can figure out the real queue depth */
-		lun_qdepth = hba->nutrs;
-	else
-		lun_qdepth = min_t(int, lun_qdepth, hba->nutrs);
-
-	dev_dbg(hba->dev, "%s: activate tcq with queue depth %d\n",
-			__func__, lun_qdepth);
-	scsi_change_queue_depth(sdev, lun_qdepth);
-}
-
-/*
- * ufshcd_get_lu_wp - returns the "b_lu_write_protect" from UNIT DESCRIPTOR
- * @hba: per-adapter instance
- * @lun: UFS device lun id
- * @b_lu_write_protect: pointer to buffer to hold the LU's write protect info
- *
- * Returns 0 in case of success and b_lu_write_protect status would be returned
- * @b_lu_write_protect parameter.
- * Returns -ENOTSUPP if reading b_lu_write_protect is not supported.
- * Returns -EINVAL in case of invalid parameters passed to this function.
- */
-static int ufshcd_get_lu_wp(struct ufs_hba *hba,
-			    u8 lun,
-			    u8 *b_lu_write_protect)
-{
-	int ret;
-
-	if (!b_lu_write_protect)
-		ret = -EINVAL;
-	/*
-	 * According to UFS device spec, RPMB LU can't be write
-	 * protected so skip reading bLUWriteProtect parameter for
-	 * it. For other W-LUs, UNIT DESCRIPTOR is not available.
-	 */
-	else if (lun >= hba->dev_info.max_lu_supported)
-		ret = -ENOTSUPP;
-	else
-		ret = ufshcd_read_unit_desc_param(hba,
-					  lun,
-					  UNIT_DESC_PARAM_LU_WR_PROTECT,
-					  b_lu_write_protect,
-					  sizeof(*b_lu_write_protect));
-	return ret;
-}
-
-/**
- * ufshcd_get_lu_power_on_wp_status - get LU's power on write protect
- * status
- * @hba: per-adapter instance
- * @sdev: pointer to SCSI device
- *
- */
-static inline void ufshcd_get_lu_power_on_wp_status(struct ufs_hba *hba,
-						    const struct scsi_device *sdev)
-{
-	if (hba->dev_info.f_power_on_wp_en &&
-	    !hba->dev_info.is_lu_power_on_wp) {
-		u8 b_lu_write_protect;
-
-		if (!ufshcd_get_lu_wp(hba, ufshcd_scsi_to_upiu_lun(sdev->lun),
-				      &b_lu_write_protect) &&
-		    (b_lu_write_protect == UFS_LU_POWER_ON_WP))
-			hba->dev_info.is_lu_power_on_wp = true;
-	}
-}
-
 /**
  * ufshcd_setup_links - associate link b/w device wlun and other luns
  * @sdev: pointer to SCSI device
@@ -4992,6 +4898,58 @@ static void ufshcd_setup_links(struct ufs_hba *hba, struct scsi_device *sdev)
 	}
 }
 
+/**
+ * ufshcd_lu_init - Initialize the relevant parameters of the LU
+ * @hba: per-adapter instance
+ * @sdev: pointer to SCSI device
+ */
+static void ufshcd_lu_init(struct ufs_hba *hba, struct scsi_device *sdev)
+{
+	int len = hba->desc_size[QUERY_DESC_IDN_UNIT];
+	u8 lun = ufshcd_scsi_to_upiu_lun(sdev->lun);
+	u8 lun_qdepth = hba->nutrs;
+	u8 *desc_buf;
+	int ret;
+
+	desc_buf = kzalloc(len, GFP_KERNEL);
+	if (!desc_buf)
+		goto set_qdepth;
+
+	ret = ufshcd_read_unit_desc_param(hba, lun, 0, desc_buf, len);
+	if (ret < 0) {
+		if (ret == -EOPNOTSUPP)
+			/* If LU doesn't support unit descriptor, its queue depth is set to 1 */
+			lun_qdepth = 1;
+		kfree(desc_buf);
+		goto set_qdepth;
+	}
+
+	if (desc_buf[UNIT_DESC_PARAM_LU_Q_DEPTH]) {
+		/*
+		 * In per-LU queueing architecture, bLUQueueDepth will not be 0, then we will
+		 * use the smaller between UFSHCI CAP.NUTRS and UFS LU bLUQueueDepth
+		 */
+		lun_qdepth = min_t(int, desc_buf[UNIT_DESC_PARAM_LU_Q_DEPTH], hba->nutrs);
+	}
+	/*
+	 * According to UFS device specification, the write protection mode is only supported by
+	 * normal LU, not supported by WLUN.
+	 */
+	if (hba->dev_info.f_power_on_wp_en && lun < hba->dev_info.max_lu_supported &&
+	    !hba->dev_info.is_lu_power_on_wp &&
+	    desc_buf[UNIT_DESC_PARAM_LU_WR_PROTECT] == UFS_LU_POWER_ON_WP)
+		hba->dev_info.is_lu_power_on_wp = true;
+
+	kfree(desc_buf);
+set_qdepth:
+	/*
+	 * For WLUNs that don't support unit descriptor, queue depth is set to 1. For LUs whose
+	 * bLUQueueDepth == 0, the queue depth is set to a maximum value that host can queue.
+	 */
+	dev_dbg(hba->dev, "Set LU %x queue depth %d\n", lun, lun_qdepth);
+	scsi_change_queue_depth(sdev, lun_qdepth);
+}
+
 /**
  * ufshcd_slave_alloc - handle initial SCSI device configurations
  * @sdev: pointer to SCSI device
@@ -5019,9 +4977,7 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev)
 	/* WRITE_SAME command is not supported */
 	sdev->no_write_same = 1;
 
-	ufshcd_set_queue_depth(sdev);
-
-	ufshcd_get_lu_power_on_wp_status(hba, sdev);
+	ufshcd_lu_init(hba, sdev);
 
 	ufshcd_setup_links(hba, sdev);