scsi: mpt3sas: lockless command submission

Performance improvement using block layer tag.

Curent driver gets scsiio tracker and free smid from link list and array
based tracking managed by driver.  Accessing list in main io path is
performance pentaly because of protection using spinlock
"scsi_lookup_lock".

In this patch:

1. Driver removes all link list access from main io path and
   use scmd->request->tag to get free smid.

2. Instead of holding 'struct scsiio_tracker' in its own pool
   driver can embed it into the scsi command.

Driver provides cmd_size in scsi_host_template, so that struct
scsiio_tracker is preallocated by scsi mid layer for each scsi command.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 37 insertions, 84 deletions

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index e6c8dec..74fca18 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -1445,74 +1445,31 @@ _scsih_is_nvme_device(u32 device_info)
 }
 
 /**
- * __scsih_scsi_lookup_get_clear - returns scmd entry without
- *						holding any lock.
+ * mpt3sas_scsih_scsi_lookup_get - returns scmd entry
  * @ioc: per adapter object
  * @smid: system request message index
  *
  * Returns the smid stored scmd pointer.
  * Then will dereference the stored scmd pointer.
  */
-static inline struct scsi_cmnd *
-__scsih_scsi_lookup_get_clear(struct MPT3SAS_ADAPTER *ioc,
-		u16 smid)
+struct scsi_cmnd *
+mpt3sas_scsih_scsi_lookup_get(struct MPT3SAS_ADAPTER *ioc, u16 smid)
 {
 	struct scsi_cmnd *scmd = NULL;
+	struct scsiio_tracker *st;
 
-	swap(scmd, ioc->scsi_lookup[smid - 1].scmd);
-
-	return scmd;
-}
-
-/**
- * _scsih_scsi_lookup_get_clear - returns scmd entry
- * @ioc: per adapter object
- * @smid: system request message index
- *
- * Returns the smid stored scmd pointer.
- * Then will derefrence the stored scmd pointer.
- */
-static inline struct scsi_cmnd *
-_scsih_scsi_lookup_get_clear(struct MPT3SAS_ADAPTER *ioc, u16 smid)
-{
-	unsigned long flags;
-	struct scsi_cmnd *scmd;
-
-	spin_lock_irqsave(&ioc->scsi_lookup_lock, flags);
-	scmd = __scsih_scsi_lookup_get_clear(ioc, smid);
-	spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
-
-	return scmd;
-}
-
-/**
- * _scsih_scsi_lookup_find_by_scmd - scmd lookup
- * @ioc: per adapter object
- * @smid: system request message index
- * @scmd: pointer to scsi command object
- * Context: This function will acquire ioc->scsi_lookup_lock.
- *
- * This will search for a scmd pointer in the scsi_lookup array,
- * returning the revelent smid.  A returned value of zero means invalid.
- */
-struct scsiio_tracker *
-_scsih_scsi_lookup_find_by_scmd(struct MPT3SAS_ADAPTER *ioc, struct scsi_cmnd
-	*scmd)
-{
-	struct scsiio_tracker *st = NULL;
-	unsigned long flags;
-	int i;
+	if (smid > 0  &&
+	    smid <= ioc->scsiio_depth - INTERNAL_SCSIIO_CMDS_COUNT) {
+		u32 unique_tag = smid - 1;
 
-	spin_lock_irqsave(&ioc->scsi_lookup_lock, flags);
-	for (i = 0; i < ioc->scsiio_depth; i++) {
-		if (ioc->scsi_lookup[i].scmd == scmd) {
-			st = &ioc->scsi_lookup[i];
-			goto out;
+		scmd = scsi_host_find_tag(ioc->shost, unique_tag);
+		if (scmd) {
+			st = scsi_cmd_priv(scmd);
+			if (st->cb_idx == 0xFF)
+				scmd = NULL;
 		}
 	}
- out:
-	spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
-	return st;
+	return scmd;
 }
 
 /**
@@ -2869,7 +2826,7 @@ scsih_abort(struct scsi_cmnd *scmd)
 {
 	struct MPT3SAS_ADAPTER *ioc = shost_priv(scmd->device->host);
 	struct MPT3SAS_DEVICE *sas_device_priv_data;
-	struct scsiio_tracker *st = NULL;
+	struct scsiio_tracker *st = scsi_cmd_priv(scmd);
 	u16 handle;
 	int r;
 
@@ -2887,9 +2844,8 @@ scsih_abort(struct scsi_cmnd *scmd)
 		goto out;
 	}
 
-	/* search for the command */
-	st = _scsih_scsi_lookup_find_by_scmd(ioc, scmd);
-	if (!st) {
+	/* check for completed command */
+	if (st == NULL || st->cb_idx == 0xFF) {
 		scmd->result = DID_RESET << 16;
 		r = SUCCESS;
 		goto out;
@@ -2911,7 +2867,7 @@ scsih_abort(struct scsi_cmnd *scmd)
 		MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK,
 		st->smid, st->msix_io, 30);
 	/* Command must be cleared after abort */
-	if (r == SUCCESS && st->scmd)
+	if (r == SUCCESS && st->cb_idx != 0xFF)
 		r = FAILED;
  out:
 	sdev_printk(KERN_INFO, scmd->device, "task abort: %s scmd(%p)\n",
@@ -4484,16 +4440,18 @@ static void
 _scsih_flush_running_cmds(struct MPT3SAS_ADAPTER *ioc)
 {
 	struct scsi_cmnd *scmd;
+	struct scsiio_tracker *st;
 	u16 smid;
-	u16 count = 0;
+	int count = 0;
 
 	for (smid = 1; smid <= ioc->scsiio_depth; smid++) {
-		scmd = _scsih_scsi_lookup_get_clear(ioc, smid);
+		scmd = mpt3sas_scsih_scsi_lookup_get(ioc, smid);
 		if (!scmd)
 			continue;
 		count++;
 		_scsih_set_satl_pending(scmd, false);
-		mpt3sas_base_free_smid(ioc, smid);
+		st = scsi_cmd_priv(scmd);
+		mpt3sas_base_clear_st(ioc, st);
 		scsi_dma_unmap(scmd);
 		if (ioc->pci_error_recovery)
 			scmd->result = DID_NO_CONNECT << 16;
@@ -4748,7 +4706,7 @@ scsih_qcmd(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
 	raid_device = sas_target_priv_data->raid_device;
 	if (raid_device && raid_device->direct_io_enabled)
 		mpt3sas_setup_direct_io(ioc, scmd,
-			raid_device, mpi_request, smid);
+			raid_device, mpi_request);
 
 	if (likely(mpi_request->Function == MPI2_FUNCTION_SCSI_IO_REQUEST)) {
 		if (sas_target_priv_data->flags & MPT_TARGET_FASTPATH_IO) {
@@ -5216,6 +5174,7 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 	Mpi25SCSIIORequest_t *mpi_request;
 	Mpi2SCSIIOReply_t *mpi_reply;
 	struct scsi_cmnd *scmd;
+	struct scsiio_tracker *st;
 	u16 ioc_status;
 	u32 xfer_cnt;
 	u8 scsi_state;
@@ -5223,16 +5182,10 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 	u32 log_info;
 	struct MPT3SAS_DEVICE *sas_device_priv_data;
 	u32 response_code = 0;
-	unsigned long flags;
 
 	mpi_reply = mpt3sas_base_get_reply_virt_addr(ioc, reply);
 
-	if (ioc->broadcast_aen_busy || ioc->pci_error_recovery ||
-			ioc->got_task_abort_from_ioctl)
-		scmd = _scsih_scsi_lookup_get_clear(ioc, smid);
-	else
-		scmd = __scsih_scsi_lookup_get_clear(ioc, smid);
-
+	scmd = mpt3sas_scsih_scsi_lookup_get(ioc, smid);
 	if (scmd == NULL)
 		return 1;
 
@@ -5257,13 +5210,11 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 	 * WARPDRIVE: If direct_io is set then it is directIO,
 	 * the failed direct I/O should be redirected to volume
 	 */
-	if (mpt3sas_scsi_direct_io_get(ioc, smid) &&
+	st = scsi_cmd_priv(scmd);
+	if (st->direct_io &&
 	     ((ioc_status & MPI2_IOCSTATUS_MASK)
 	      != MPI2_IOCSTATUS_SCSI_TASK_TERMINATED)) {
-		spin_lock_irqsave(&ioc->scsi_lookup_lock, flags);
-		ioc->scsi_lookup[smid - 1].scmd = scmd;
-		spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
-		mpt3sas_scsi_direct_io_set(ioc, smid, 0);
+		st->direct_io = 0;
 		memcpy(mpi_request->CDB.CDB32, scmd->cmnd, scmd->cmd_len);
 		mpi_request->DevHandle =
 		    cpu_to_le16(sas_device_priv_data->sas_target->handle);
@@ -5441,9 +5392,9 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
  out:
 
 	scsi_dma_unmap(scmd);
-
+	mpt3sas_base_free_smid(ioc, smid);
 	scmd->scsi_done(scmd);
-	return 1;
+	return 0;
 }
 
 /**
@@ -7428,10 +7379,10 @@ _scsih_sas_broadcast_primitive_event(struct MPT3SAS_ADAPTER *ioc,
 	for (smid = 1; smid <= ioc->scsiio_depth; smid++) {
 		if (ioc->shost_recovery)
 			goto out;
-		st = &ioc->scsi_lookup[smid - 1];
-		scmd = st->scmd;
+		scmd = mpt3sas_scsih_scsi_lookup_get(ioc, smid);
 		if (!scmd)
 			continue;
+		st = scsi_cmd_priv(scmd);
 		sdev = scmd->device;
 		sas_device_priv_data = sdev->hostdata;
 		if (!sas_device_priv_data || !sas_device_priv_data->sas_target)
@@ -7454,7 +7405,7 @@ _scsih_sas_broadcast_primitive_event(struct MPT3SAS_ADAPTER *ioc,
 
 		spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
 		r = mpt3sas_scsih_issue_tm(ioc, handle, lun,
-			MPI2_SCSITASKMGMT_TASKTYPE_QUERY_TASK, smid,
+			MPI2_SCSITASKMGMT_TASKTYPE_QUERY_TASK, st->smid,
 			st->msix_io, 30);
 		if (r == FAILED) {
 			sdev_printk(KERN_WARNING, sdev,
@@ -7495,9 +7446,9 @@ _scsih_sas_broadcast_primitive_event(struct MPT3SAS_ADAPTER *ioc,
 			goto out_no_lock;
 
 		r = mpt3sas_scsih_issue_tm(ioc, handle, sdev->lun,
-			MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK, smid,
+			MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK, st->smid,
 			st->msix_io, 30);
-		if (r == FAILED || st->scmd) {
+		if (r == FAILED || st->cb_idx != 0xFF) {
 			sdev_printk(KERN_WARNING, sdev,
 			    "mpt3sas_scsih_issue_tm: ABORT_TASK: FAILED : "
 			    "scmd(%p)\n", scmd);
@@ -10303,6 +10254,7 @@ static struct scsi_host_template mpt2sas_driver_template = {
 	.shost_attrs			= mpt3sas_host_attrs,
 	.sdev_attrs			= mpt3sas_dev_attrs,
 	.track_queue_depth		= 1,
+	.cmd_size			= sizeof(struct scsiio_tracker),
 };
 
 /* raid transport support for SAS 2.0 HBA devices */
@@ -10341,6 +10293,7 @@ static struct scsi_host_template mpt3sas_driver_template = {
 	.shost_attrs			= mpt3sas_host_attrs,
 	.sdev_attrs			= mpt3sas_dev_attrs,
 	.track_queue_depth		= 1,
+	.cmd_size			= sizeof(struct scsiio_tracker),
 };
 
 /* raid transport support for SAS 3.0 HBA devices */