[PATCH 33/47] cxlflash: use dedicated reset command in send_tmf()

[Hannes Reinecke <hare@xxxxxxx>]

From: Hannes Reinecke <hare@xxxxxxxx>

Reduce the queue depth by 1, and use this command as a dedicated
reset command send_tmf().

Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
---
 drivers/scsi/cxlflash/common.h |  3 ++-
 drivers/scsi/cxlflash/main.c   | 23 ++++++++++++++++-------
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h
index 6d95e8e..b2b3bdc 100644
--- a/drivers/scsi/cxlflash/common.h
+++ b/drivers/scsi/cxlflash/common.h
@@ -54,7 +54,8 @@
 
 /* Command management definitions */
 #define CXLFLASH_MAX_CMDS               256
-#define CXLFLASH_MAX_CMDS_PER_LUN       CXLFLASH_MAX_CMDS
+#define CXLFLASH_MAX_CMDS_PER_LUN       CXLFLASH_MAX_CMDS - 1
+#define CXLFLASH_RESET_CMD              255
 
 /* RRQ for master issued cmds */
 #define NUM_RRQ_ENTRY                   CXLFLASH_MAX_CMDS
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 462e8fc..b33e3e7 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -23,6 +23,7 @@
 
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
+#include <scsi/scsi_tcq.h>
 #include <uapi/scsi/cxlflash_ioctl.h>
 
 #include "main.h"
@@ -460,15 +461,16 @@ static u32 cmd_to_target_hwq(struct Scsi_Host *host, struct scsi_cmnd *scp,
 /**
  * send_tmf() - sends a Task Management Function (TMF)
  * @afu:	AFU to checkout from.
- * @scp:	SCSI command from stack describing target.
+ * @sdev:	SCSI device to reset.
  * @tmfcmd:	TMF command to send.
  *
  * Return:
  *	0 on success, SCSI_MLQUEUE_HOST_BUSY or -errno on failure
  */
-static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)
+static int send_tmf(struct afu *afu, struct scsi_device *sdev, u64 tmfcmd)
 {
-	struct Scsi_Host *host = scp->device->host;
+	struct scsi_cmnd *scp;
+	struct Scsi_Host *host = sdev->host;
 	struct cxlflash_cfg *cfg = shost_priv(host);
 	struct afu_cmd *cmd = NULL;
 	struct device *dev = &cfg->dev->dev;
@@ -498,14 +500,21 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)
 	cfg->tmf_active = true;
 	spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
 
+	scp = scsi_host_find_tag(host, CXLFLASH_RESET_CMD);
+	scp->device = sdev;
+	cmd = sc_to_afucz(scp);
+	hwq_index = cmd_to_target_hwq(host, scp, afu);
+	hwq = get_hwq(afu, hwq_index);
+
+	cmd->scp = scp;
 	cmd->parent = afu;
 	cmd->cmd_tmf = true;
 	cmd->hwq_index = hwq_index;
 
 	cmd->rcb.ctx_id = hwq->ctx_hndl;
 	cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
-	cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);
-	cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
+	cmd->rcb.port_sel = CHAN2PORTMASK(sdev->channel);
+	cmd->rcb.lun_id = lun_to_lunid(sdev->lun);
 	cmd->rcb.req_flags = (SISL_REQ_FLAGS_PORT_LUN_ID |
 			      SISL_REQ_FLAGS_SUP_UNDERRUN |
 			      SISL_REQ_FLAGS_TMF_CMD);
@@ -2448,7 +2457,7 @@ static int cxlflash_eh_device_reset_handler(struct scsi_cmnd *scp)
 retry:
 	switch (cfg->state) {
 	case STATE_NORMAL:
-		rcr = send_tmf(afu, scp, TMF_LUN_RESET);
+		rcr = send_tmf(afu, sdev, TMF_LUN_RESET);
 		if (unlikely(rcr))
 			rc = FAILED;
 		break;
@@ -3139,7 +3148,7 @@ static ssize_t mode_show(struct device *dev,
 	.eh_host_reset_handler = cxlflash_eh_host_reset_handler,
 	.change_queue_depth = cxlflash_change_queue_depth,
 	.cmd_per_lun = CXLFLASH_MAX_CMDS_PER_LUN,
-	.can_queue = CXLFLASH_MAX_CMDS,
+	.can_queue = CXLFLASH_MAX_CMDS - 1,
 	.cmd_size = sizeof(struct afu_cmd) + __alignof__(struct afu_cmd) - 1,
 	.this_id = -1,
 	.sg_tablesize = 1,	/* No scatter gather support */
-- 
1.8.5.6