[PATCH 2/4] scsi: mpt3sas: use private counter for tracking inflight per-LUN commands

[Ming Lei <ming.lei@redhat.com>]

Prepare for bypassing sdev->device_busy for improving performance on
fast SCSI storage device, so sdev->device_busy can't be relied
any more.

mpt3sas may need one such counter for balancing load among LUNs in
some specific setting, so add one private counter for this purpose.

Cc: Sathya Prakash <sathya.prakash@broadcom.com>
Cc: Chaitra P B <chaitra.basappa@broadcom.com>
Cc: Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>,
Cc: Hannes Reinecke <hare@suse.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c  |  3 ++-
 drivers/scsi/mpt3sas/mpt3sas_base.h  |  1 +
 drivers/scsi/mpt3sas/mpt3sas_scsih.c | 15 +++++++++++++--
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index fea3cb6a090b..9c2d374b3157 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -3480,12 +3480,13 @@ static inline u8
 _base_get_high_iops_msix_index(struct MPT3SAS_ADAPTER *ioc,
 	struct scsi_cmnd *scmd)
 {
+	struct MPT3SAS_DEVICE *sas_device_priv_data = scmd->device->hostdata;
 	/**
 	 * Round robin the IO interrupts among the high iops
 	 * reply queues in terms of batch count 16 when outstanding
 	 * IOs on the target device is >=8.
 	 */
-	if (atomic_read(&scmd->device->device_busy) >
+	if (atomic_read(&sas_device_priv_data->active_cmds) >
 	    MPT3SAS_DEVICE_HIGH_IOPS_DEPTH)
 		return base_mod64((
 		    atomic64_add_return(1, &ioc->high_iops_outstanding) /
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h b/drivers/scsi/mpt3sas/mpt3sas_base.h
index faca0a5e71f8..9e9f319bb636 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -467,6 +467,7 @@ struct MPT3SAS_DEVICE {
 	 * thing while a SATL command is pending.
 	 */
 	unsigned long ata_command_pending;
+	atomic_t active_cmds;
 
 };
 
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index c8e512ba6d39..194960dae1d6 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -1770,6 +1770,7 @@ scsih_slave_alloc(struct scsi_device *sdev)
 
 	sas_device_priv_data->lun = sdev->lun;
 	sas_device_priv_data->flags = MPT_DEVICE_FLAGS_INIT;
+	atomic_set(&sas_device_priv_data->active_cmds, 0);
 
 	starget = scsi_target(sdev);
 	sas_target_priv_data = starget->hostdata;
@@ -2884,6 +2885,7 @@ scsih_abort(struct scsi_cmnd *scmd)
 	    ioc->remove_host) {
 		sdev_printk(KERN_INFO, scmd->device,
 			"device been deleted! scmd(%p)\n", scmd);
+		atomic_dec(&sas_device_priv_data->active_cmds);
 		scmd->result = DID_NO_CONNECT << 16;
 		scmd->scsi_done(scmd);
 		r = SUCCESS;
@@ -2993,7 +2995,7 @@ scsih_dev_reset(struct scsi_cmnd *scmd)
 		MPI2_SCSITASKMGMT_TASKTYPE_LOGICAL_UNIT_RESET, 0, 0,
 		tr_timeout, tr_method);
 	/* Check for busy commands after reset */
-	if (r == SUCCESS && atomic_read(&scmd->device->device_busy))
+	if (r == SUCCESS && atomic_read(&sas_device_priv_data->active_cmds))
 		r = FAILED;
  out:
 	sdev_printk(KERN_INFO, scmd->device, "device reset: %s scmd(%p)\n",
@@ -4517,9 +4519,12 @@ _scsih_flush_running_cmds(struct MPT3SAS_ADAPTER *ioc)
 	int count = 0;
 
 	for (smid = 1; smid <= ioc->scsiio_depth; smid++) {
+		struct MPT3SAS_DEVICE *sas_device_priv_data;
+
 		scmd = mpt3sas_scsih_scsi_lookup_get(ioc, smid);
 		if (!scmd)
 			continue;
+		sas_device_priv_data = scmd->device->hostdata;
 		count++;
 		_scsih_set_satl_pending(scmd, false);
 		st = scsi_cmd_priv(scmd);
@@ -4529,6 +4534,7 @@ _scsih_flush_running_cmds(struct MPT3SAS_ADAPTER *ioc)
 			scmd->result = DID_NO_CONNECT << 16;
 		else
 			scmd->result = DID_RESET << 16;
+		atomic_dec(&sas_device_priv_data->active_cmds);
 		scmd->scsi_done(scmd);
 	}
 	dtmprintk(ioc, ioc_info(ioc, "completing %d cmds\n", count));
@@ -4756,11 +4762,14 @@ scsih_qcmd(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
 	    mpi_request->LUN);
 	memcpy(mpi_request->CDB.CDB32, scmd->cmnd, scmd->cmd_len);
 
+	atomic_inc(&sas_device_priv_data->active_cmds);
+
 	if (mpi_request->DataLength) {
 		pcie_device = sas_target_priv_data->pcie_dev;
 		if (ioc->build_sg_scmd(ioc, scmd, smid, pcie_device)) {
 			mpt3sas_base_free_smid(ioc, smid);
 			_scsih_set_satl_pending(scmd, false);
+			atomic_dec(&sas_device_priv_data->active_cmds);
 			goto out;
 		}
 	} else
@@ -5207,6 +5216,7 @@ _scsih_smart_predicted_fault(struct MPT3SAS_ADAPTER *ioc, u16 handle)
 static u8
 _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 {
+	struct MPT3SAS_DEVICE *sas_device_priv_data;
 	Mpi25SCSIIORequest_t *mpi_request;
 	Mpi2SCSIIOReply_t *mpi_reply;
 	struct scsi_cmnd *scmd;
@@ -5216,7 +5226,6 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 	u8 scsi_state;
 	u8 scsi_status;
 	u32 log_info;
-	struct MPT3SAS_DEVICE *sas_device_priv_data;
 	u32 response_code = 0;
 
 	mpi_reply = mpt3sas_base_get_reply_virt_addr(ioc, reply);
@@ -5225,6 +5234,7 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 	if (scmd == NULL)
 		return 1;
 
+	sas_device_priv_data = scmd->device->hostdata;
 	_scsih_set_satl_pending(scmd, false);
 
 	mpi_request = mpt3sas_base_get_msg_frame(ioc, smid);
@@ -5431,6 +5441,7 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
 
 	scsi_dma_unmap(scmd);
 	mpt3sas_base_free_smid(ioc, smid);
+	atomic_dec(&sas_device_priv_data->active_cmds);
 	scmd->scsi_done(scmd);
 	return 0;
 }
-- 
2.20.1