scsi: ufs: core: Switch to scsi_get_internal_cmd()

Instead of storing the tag of the reserved command in hba->reserved_slot,
use scsi_get_internal_cmd() and scsi_put_internal_cmd() to allocate the
tag for the reserved command dynamically. Add
ufshcd_queue_reserved_command() for submitting reserved commands. Add
support in ufshcd_abort() for device management commands. Use
blk_execute_rq() for submitting reserved commands. Remove the code and
data structures that became superfluous. This includes
ufshcd_wait_for_dev_cmd(), hba->reserved_slot and ufs_dev_cmd.complete.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251031204029.2883185-29-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/core/ufs-mcq.c

@@ -479,9 +479,6 @@ int ufshcd_mcq_init(struct ufs_hba *hba)
 		mutex_init(&hwq->sq_mutex);
 	}
 
-	/* The very first HW queue serves device commands */
-	hba->dev_cmd_queue = &hba->uhq[0];
-
 	host->host_tagset = 1;
 	return 0;
 }
@@ -536,6 +533,7 @@ int ufshcd_mcq_sq_cleanup(struct ufs_hba *hba, int task_tag)
 {
 	struct scsi_cmnd *cmd = ufshcd_tag_to_cmd(hba, task_tag);
 	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
+	struct request *rq = scsi_cmd_to_rq(cmd);
 	struct ufs_hw_queue *hwq;
 	void __iomem *reg, *opr_sqd_base;
 	u32 nexus, id, val;
@@ -544,15 +542,12 @@ int ufshcd_mcq_sq_cleanup(struct ufs_hba *hba, int task_tag)
 	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_RTC)
 		return -ETIMEDOUT;
 
-	if (task_tag != hba->reserved_slot) {
+	if (!cmd)
-		if (!cmd)
+		return -EINVAL;
-			return -EINVAL;
+
-		hwq = ufshcd_mcq_req_to_hwq(hba, scsi_cmd_to_rq(cmd));
+	hwq = ufshcd_mcq_req_to_hwq(hba, rq);
-		if (!hwq)
+	if (!hwq)
-			return 0;
+		return 0;
-	} else {
-		hwq = hba->dev_cmd_queue;
-	}
 
 	id = hwq->id;
 

drivers/ufs/core/ufshcd-priv.h

@@ -369,30 +369,7 @@ static inline bool ufs_is_valid_unit_desc_lun(struct ufs_dev_info *dev_info, u8
 static inline struct scsi_cmnd *ufshcd_tag_to_cmd(struct ufs_hba *hba, u32 tag)
 {
 	struct blk_mq_tags *tags = hba->host->tag_set.shared_tags;
-	struct request *rq;
+	struct request *rq = blk_mq_tag_to_rq(tags, tag);
-
-	/*
-	 * Handle reserved tags differently because the UFS driver does not
-	 * call blk_mq_alloc_request() for allocating reserved requests.
-	 * Allocating reserved tags with blk_mq_alloc_request() would require
-	 * the following:
-	 * - Allocate an additional request queue from &hba->host->tag_set for
-	 *   allocating reserved requests from.
-	 * - For that request queue, allocate a SCSI device.
-	 * - Calling blk_mq_alloc_request(hba->dev_mgmt_queue, REQ_OP_DRV_OUT,
-	 *   BLK_MQ_REQ_RESERVED) for allocating a reserved request and
-	 *   blk_mq_free_request() for freeing reserved requests.
-	 * - Set the .device pointer for these reserved requests.
-	 * - Submit reserved requests with blk_execute_rq().
-	 * - Modify ufshcd_queuecommand() such that it handles reserved requests
-	 *   in another way than SCSI requests.
-	 * - Modify ufshcd_compl_one_cqe() such that it calls scsi_done() for
-	 *   device management commands.
-	 * - Modify all callback functions called by blk_mq_tagset_busy_iter()
-	 *   calls in the UFS driver and skip device management commands.
-	 */
-	rq = tag < UFSHCD_NUM_RESERVED ? tags->static_rqs[tag] :
-					 blk_mq_tag_to_rq(tags, tag);
 
 	if (WARN_ON_ONCE(!rq))
 		return NULL;

drivers/ufs/core/ufshcd.c

@@ -2350,13 +2350,10 @@ static void ufshcd_update_monitor(struct ufs_hba *hba, struct scsi_cmnd *cmd)
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 }
 
-/*
+/* Returns %true for SCSI commands and %false for device management commands. */
- * Returns %true for SCSI commands and %false for device management commands.
- * Must not be called for SCSI commands that have not yet been started.
- */
 static bool ufshcd_is_scsi_cmd(struct scsi_cmnd *cmd)
 {
-	return blk_mq_request_started(scsi_cmd_to_rq(cmd));
+	return !blk_mq_is_reserved_rq(scsi_cmd_to_rq(cmd));
 }
 
 /**
@@ -2487,7 +2484,6 @@ static inline int ufshcd_hba_capabilities(struct ufs_hba *hba)
 	hba->nutrs = (hba->capabilities & MASK_TRANSFER_REQUESTS_SLOTS_SDB) + 1;
 	hba->nutmrs =
 	((hba->capabilities & MASK_TASK_MANAGEMENT_REQUEST_SLOTS) >> 16) + 1;
-	hba->reserved_slot = 0;
 
 	hba->nortt = FIELD_GET(MASK_NUMBER_OUTSTANDING_RTT, hba->capabilities) + 1;
 
@@ -3116,6 +3112,20 @@ out:
 	return err;
 }
 
+static int ufshcd_queue_reserved_command(struct Scsi_Host *host,
+					 struct scsi_cmnd *cmd)
+{
+	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
+	struct request *rq = scsi_cmd_to_rq(cmd);
+	struct ufs_hba *hba = shost_priv(host);
+	struct ufs_hw_queue *hwq =
+		hba->mcq_enabled ? ufshcd_mcq_req_to_hwq(hba, rq) : NULL;
+
+	ufshcd_add_query_upiu_trace(hba, UFS_QUERY_SEND, lrbp->ucd_req_ptr);
+	ufshcd_send_command(hba, cmd, hwq);
+	return 0;
+}
+
 static void ufshcd_setup_dev_cmd(struct ufs_hba *hba, struct scsi_cmnd *cmd,
 				 enum dev_cmd_type cmd_type, u8 lun, int tag)
 {
@@ -3245,84 +3255,6 @@ ufshcd_dev_cmd_completion(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 	return err;
 }
 
-/*
- * Return: 0 upon success; > 0 in case the UFS device reported an OCS error;
- * < 0 if another error occurred.
- */
-static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba,
-		struct ufshcd_lrb *lrbp, int max_timeout)
-{
-	struct scsi_cmnd *cmd = (struct scsi_cmnd *)lrbp - 1;
-	const int tag = scsi_cmd_to_rq(cmd)->tag;
-	unsigned long time_left = msecs_to_jiffies(max_timeout);
-	unsigned long flags;
-	bool pending;
-	int err;
-
-retry:
-	time_left = wait_for_completion_timeout(&hba->dev_cmd.complete,
-						time_left);
-
-	if (likely(time_left)) {
-		err = ufshcd_get_tr_ocs(lrbp, NULL);
-	} else {
-		err = -ETIMEDOUT;
-		dev_dbg(hba->dev, "%s: dev_cmd request timedout, tag %d\n",
-			__func__, tag);
-
-		/* MCQ mode */
-		if (hba->mcq_enabled) {
-			/* successfully cleared the command, retry if needed */
-			if (ufshcd_clear_cmd(hba, tag) == 0)
-				err = -EAGAIN;
-			return err;
-		}
-
-		/* SDB mode */
-		if (ufshcd_clear_cmd(hba, tag) == 0) {
-			/* successfully cleared the command, retry if needed */
-			err = -EAGAIN;
-			/*
-			 * Since clearing the command succeeded we also need to
-			 * clear the task tag bit from the outstanding_reqs
-			 * variable.
-			 */
-			spin_lock_irqsave(&hba->outstanding_lock, flags);
-			pending = test_bit(tag, &hba->outstanding_reqs);
-			if (pending)
-				__clear_bit(tag, &hba->outstanding_reqs);
-			spin_unlock_irqrestore(&hba->outstanding_lock, flags);
-
-			if (!pending) {
-				/*
-				 * The completion handler ran while we tried to
-				 * clear the command.
-				 */
-				time_left = 1;
-				goto retry;
-			}
-		} else {
-			dev_err(hba->dev, "%s: failed to clear tag %d\n",
-				__func__, tag);
-
-			spin_lock_irqsave(&hba->outstanding_lock, flags);
-			pending = test_bit(tag, &hba->outstanding_reqs);
-			spin_unlock_irqrestore(&hba->outstanding_lock, flags);
-
-			if (!pending) {
-				/*
-				 * The completion handler ran while we tried to
-				 * clear the command.
-				 */
-				time_left = 1;
-				goto retry;
-			}
-		}
-	}
-
-	return err;
-}
-
 static void ufshcd_dev_man_lock(struct ufs_hba *hba)
 {
 	ufshcd_hold(hba);
@@ -3337,6 +3269,24 @@ static void ufshcd_dev_man_unlock(struct ufs_hba *hba)
 	ufshcd_release(hba);
 }
 
+static struct scsi_cmnd *ufshcd_get_dev_mgmt_cmd(struct ufs_hba *hba)
+{
+	/*
+	 * The caller must hold this lock to guarantee that the NOWAIT
+	 * allocation will succeed.
+	 */
+	lockdep_assert_held(&hba->dev_cmd.lock);
+
+	return scsi_get_internal_cmd(
+		hba->host->pseudo_sdev, DMA_TO_DEVICE,
+		BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
+}
+
+static void ufshcd_put_dev_mgmt_cmd(struct scsi_cmnd *cmd)
+{
+	scsi_put_internal_cmd(cmd);
+}
+
 /*
  * Return: 0 upon success; > 0 in case the UFS device reported an OCS error;
  * < 0 if another error occurred.
@@ -3345,16 +3295,14 @@ static int ufshcd_issue_dev_cmd(struct ufs_hba *hba, struct scsi_cmnd *cmd,
 				const u32 tag, int timeout)
 {
 	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
-	int err;
+	struct request *rq = scsi_cmd_to_rq(cmd);
+	blk_status_t sts;
 
-	ufshcd_add_query_upiu_trace(hba, UFS_QUERY_SEND, lrbp->ucd_req_ptr);
+	rq->timeout = timeout;
-	ufshcd_send_command(hba, cmd, hba->dev_cmd_queue);
+	sts = blk_execute_rq(rq, true);
-	err = ufshcd_wait_for_dev_cmd(hba, lrbp, timeout);
+	if (sts != BLK_STS_OK)
-
+		return blk_status_to_errno(sts);
-	ufshcd_add_query_upiu_trace(hba, err ? UFS_QUERY_ERR : UFS_QUERY_COMP,
+	return lrbp->utr_descriptor_ptr->header.ocs;
-				    (struct utp_upiu_req *)lrbp->ucd_rsp_ptr);
-
-	return err;
 }
 
 /**
@@ -3372,23 +3320,31 @@ static int ufshcd_issue_dev_cmd(struct ufs_hba *hba, struct scsi_cmnd *cmd,
 static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
 		enum dev_cmd_type cmd_type, int timeout)
 {
-	const u32 tag = hba->reserved_slot;
+	struct scsi_cmnd *cmd = ufshcd_get_dev_mgmt_cmd(hba);
-	struct scsi_cmnd *cmd = ufshcd_tag_to_cmd(hba, tag);
 	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
+	u32 tag;
 	int err;
 
-	/* Protects use of hba->reserved_slot. */
+	/* Protects use of hba->dev_cmd. */
 	lockdep_assert_held(&hba->dev_cmd.lock);
 
+	if (WARN_ON_ONCE(!cmd))
+		return -ENOMEM;
+
+	tag = scsi_cmd_to_rq(cmd)->tag;
+
 	err = ufshcd_compose_dev_cmd(hba, cmd, cmd_type, tag);
 	if (unlikely(err))
-		return err;
+		goto out;
 
 	err = ufshcd_issue_dev_cmd(hba, cmd, tag, timeout);
-	if (err)
+	if (err == 0)
-		return err;
+		err = ufshcd_dev_cmd_completion(hba, lrbp);
 
-	return ufshcd_dev_cmd_completion(hba, lrbp);
+out:
+	ufshcd_put_dev_mgmt_cmd(cmd);
+
+	return err;
 }
 
 /**
@@ -5658,6 +5614,10 @@ void ufshcd_compl_one_cqe(struct ufs_hba *hba, int task_tag,
 	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
 	enum utp_ocs ocs;
 
+	if (WARN_ONCE(!cmd, "cqe->command_desc_base_addr = %#llx\n",
+		      le64_to_cpu(cqe->command_desc_base_addr)))
+		return;
+
 	if (hba->monitor.enabled) {
 		lrbp->compl_time_stamp = ktime_get();
 		lrbp->compl_time_stamp_local_clock = local_clock();
@@ -5668,15 +5628,21 @@ void ufshcd_compl_one_cqe(struct ufs_hba *hba, int task_tag,
 		ufshcd_add_command_trace(hba, cmd, UFS_CMD_COMP);
 		cmd->result = ufshcd_transfer_rsp_status(hba, cmd, cqe);
 		ufshcd_release_scsi_cmd(hba, cmd);
-		/* Do not touch lrbp after scsi done */
-		scsi_done(cmd);
 	} else {
 		if (cqe) {
 			ocs = cqe->overall_status & MASK_OCS;
 			lrbp->utr_descriptor_ptr->header.ocs = ocs;
+		} else {
+			ocs = lrbp->utr_descriptor_ptr->header.ocs;
 		}
-		complete(&hba->dev_cmd.complete);
+		ufshcd_add_query_upiu_trace(
+			hba,
+			ocs == OCS_SUCCESS ? UFS_QUERY_COMP : UFS_QUERY_ERR,
+			(struct utp_upiu_req *)lrbp->ucd_rsp_ptr);
+		cmd->result = 0;
 	}
+	/* Do not touch lrbp after scsi_done() has been called. */
+	scsi_done(cmd);
 }
 
 /**
@@ -7386,15 +7352,20 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba,
 					enum dev_cmd_type cmd_type,
 					enum query_opcode desc_op)
 {
-	const u32 tag = hba->reserved_slot;
+	struct scsi_cmnd *cmd = ufshcd_get_dev_mgmt_cmd(hba);
-	struct scsi_cmnd *cmd = ufshcd_tag_to_cmd(hba, tag);
 	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
+	u32 tag;
 	int err = 0;
 	u8 upiu_flags;
 
-	/* Protects use of hba->reserved_slot. */
+	/* Protects use of hba->dev_cmd. */
 	lockdep_assert_held(&hba->dev_cmd.lock);
 
+	if (WARN_ON_ONCE(!cmd))
+		return -ENOMEM;
+
+	tag = scsi_cmd_to_rq(cmd)->tag;
+
 	ufshcd_setup_dev_cmd(hba, cmd, cmd_type, 0, tag);
 
 	ufshcd_prepare_req_desc_hdr(hba, lrbp, &upiu_flags, DMA_NONE, 0);
@@ -7417,7 +7388,7 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba,
 
 	err = ufshcd_issue_dev_cmd(hba, cmd, tag, dev_cmd_timeout);
 	if (err)
-		return err;
+		goto put_dev_mgmt_cmd;
 
 	/* just copy the upiu response as it is */
 	memcpy(rsp_upiu, lrbp->ucd_rsp_ptr, sizeof(*rsp_upiu));
@@ -7438,6 +7409,9 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba,
 		}
 	}
 
+put_dev_mgmt_cmd:
+	ufshcd_put_dev_mgmt_cmd(cmd);
+
 	return err;
 }
 
@@ -7531,9 +7505,9 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
 			 struct ufs_ehs *rsp_ehs, int sg_cnt, struct scatterlist *sg_list,
 			 enum dma_data_direction dir)
 {
-	const u32 tag = hba->reserved_slot;
+	struct scsi_cmnd *cmd;
-	struct scsi_cmnd *cmd = ufshcd_tag_to_cmd(hba, tag);
+	struct ufshcd_lrb *lrbp;
-	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
+	u32 tag;
 	int err = 0;
 	int result;
 	u8 upiu_flags;
@@ -7541,9 +7515,18 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
 	u16 ehs_len;
 	int ehs = (hba->capabilities & MASK_EHSLUTRD_SUPPORTED) ? 2 : 0;
 
-	/* Protects use of hba->reserved_slot. */
 	ufshcd_dev_man_lock(hba);
 
+	cmd = ufshcd_get_dev_mgmt_cmd(hba);
+
+	if (WARN_ON_ONCE(!cmd)) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	lrbp = scsi_cmd_priv(cmd);
+	tag = scsi_cmd_to_rq(cmd)->tag;
+
 	ufshcd_setup_dev_cmd(hba, cmd, DEV_CMD_TYPE_RPMB, UFS_UPIU_RPMB_WLUN,
 			     tag);
 
@@ -7564,7 +7547,7 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
 
 	err = ufshcd_issue_dev_cmd(hba, cmd, tag, ADVANCED_RPMB_REQ_TIMEOUT);
 	if (err)
-		return err;
+		goto put_dev_mgmt_cmd;
 
 	err = ufshcd_dev_cmd_completion(hba, lrbp);
 	if (!err) {
@@ -7590,6 +7573,10 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
 		}
 	}
 
+put_dev_mgmt_cmd:
+	ufshcd_put_dev_mgmt_cmd(cmd);
+
+unlock:
 	ufshcd_dev_man_unlock(hba);
 
 	return err ? : result;
@@ -7760,7 +7747,8 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 {
 	struct Scsi_Host *host = cmd->device->host;
 	struct ufs_hba *hba = shost_priv(host);
-	int tag = scsi_cmd_to_rq(cmd)->tag;
+	struct request *rq = scsi_cmd_to_rq(cmd);
+	int tag = rq->tag;
 	struct ufshcd_lrb *lrbp = scsi_cmd_priv(cmd);
 	unsigned long flags;
 	int err = FAILED;
@@ -7790,7 +7778,8 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	 * to reduce repeated printouts. For other aborted requests only print
 	 * basic details.
 	 */
-	scsi_print_command(cmd);
+	if (ufshcd_is_scsi_cmd(cmd))
+		scsi_print_command(cmd);
 	if (!hba->req_abort_count) {
 		ufshcd_update_evt_hist(hba, UFS_EVT_ABORT, tag);
 		ufshcd_print_evt_hist(hba);
@@ -7842,7 +7831,10 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 		goto release;
 	}
 
-	err = ufshcd_try_to_abort_task(hba, tag);
+	if (blk_mq_is_reserved_rq(rq))
+		err = ufshcd_clear_cmd(hba, tag);
+	else
+		err = ufshcd_try_to_abort_task(hba, tag);
 	if (err) {
 		dev_err(hba->dev, "%s: failed with err %d\n", __func__, err);
 		ufshcd_set_req_abort_skip(hba, hba->outstanding_reqs);
@@ -9212,6 +9204,7 @@ static const struct scsi_host_template ufshcd_driver_template = {
 	.cmd_size		= sizeof(struct ufshcd_lrb),
 	.init_cmd_priv		= ufshcd_init_cmd_priv,
 	.queuecommand		= ufshcd_queuecommand,
+	.queue_reserved_command	= ufshcd_queue_reserved_command,
 	.nr_reserved_cmds	= UFSHCD_NUM_RESERVED,
 	.mq_poll		= ufshcd_poll,
 	.sdev_init		= ufshcd_sdev_init,
@@ -10764,8 +10757,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	 */
 	hba->vcc_off_delay_us = 2000;
 
-	init_completion(&hba->dev_cmd.complete);
-
 	err = ufshcd_hba_init(hba);
 	if (err)
 		goto out_error;

include/ufs/ufshcd.h

@@ -236,13 +236,11 @@ struct ufs_query {
  * struct ufs_dev_cmd - all assosiated fields with device management commands
  * @type: device management command type - Query, NOP OUT
  * @lock: lock to allow one command at a time
- * @complete: internal commands completion
  * @query: Device management query information
  */
 struct ufs_dev_cmd {
 	enum dev_cmd_type type;
 	struct mutex lock;
-	struct completion complete;
 	struct ufs_query query;
 };
 
@@ -838,7 +836,6 @@ enum ufshcd_mcq_opr {
  * @nutrs: Transfer Request Queue depth supported by controller
  * @nortt - Max outstanding RTTs supported by controller
  * @nutmrs: Task Management Queue depth supported by controller
- * @reserved_slot: Used to submit device commands. Protected by @dev_cmd.lock.
  * @ufs_version: UFS Version to which controller complies
  * @vops: pointer to variant specific operations
  * @vps: pointer to variant specific parameters
@@ -929,7 +926,6 @@ enum ufshcd_mcq_opr {
  * @res: array of resource info of MCQ registers
  * @mcq_base: Multi circular queue registers base address
  * @uhq: array of supported hardware queues
- * @dev_cmd_queue: Queue for issuing device management commands
  * @mcq_opr: MCQ operation and runtime registers
  * @ufs_rtc_update_work: A work for UFS RTC periodic update
  * @pm_qos_req: PM QoS request handle
@@ -981,7 +977,6 @@ struct ufs_hba {
 	int nortt;
 	u32 mcq_capabilities;
 	int nutmrs;
-	u32 reserved_slot;
 	u32 ufs_version;
 	const struct ufs_hba_variant_ops *vops;
 	struct ufs_hba_variant_params *vps;
@@ -1099,7 +1094,6 @@ struct ufs_hba {
 	bool mcq_esi_enabled;
 	void __iomem *mcq_base;
 	struct ufs_hw_queue *uhq;
-	struct ufs_hw_queue *dev_cmd_queue;
 	struct ufshcd_mcq_opr_info_t mcq_opr[OPR_MAX];
 
 	struct delayed_work ufs_rtc_update_work;