scsi: mesh: Move the SCSI pointer to private command data

Set .cmd_size in the SCSI host template instead of using the SCSI pointer
from struct scsi_cmnd. This patch prepares for removal of the SCSI pointer
from struct scsi_cmnd.

Link: https://lore.kernel.org/r/20220218195117.25689-35-bvanassche@acm.orgReviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mesh.c

@@ -586,10 +586,12 @@ static void mesh_done(struct mesh_state *ms, int start_next)
 	ms->current_req = NULL;
 	tp->current_req = NULL;
 	if (cmd) {
+		struct scsi_pointer *scsi_pointer = mesh_scsi_pointer(cmd);
+
 		set_host_byte(cmd, ms->stat);
-		set_status_byte(cmd, cmd->SCp.Status);
+		set_status_byte(cmd, scsi_pointer->Status);
 		if (ms->stat == DID_OK)
-			scsi_msg_to_host_byte(cmd, cmd->SCp.Message);
+			scsi_msg_to_host_byte(cmd, scsi_pointer->Message);
 		if (DEBUG_TARGET(cmd)) {
 			printk(KERN_DEBUG "mesh_done: result = %x, data_ptr=%d, buflen=%d\n",
 			       cmd->result, ms->data_ptr, scsi_bufflen(cmd));
@@ -603,7 +605,7 @@ static void mesh_done(struct mesh_state *ms, int start_next)
 			}
 #endif
 		}
-		cmd->SCp.this_residual -= ms->data_ptr;
+		scsi_pointer->this_residual -= ms->data_ptr;
 		scsi_done(cmd);
 	}
 	if (start_next) {
@@ -1171,7 +1173,7 @@ static void handle_msgin(struct mesh_state *ms)
 	if (ms->n_msgin < msgin_length(ms))
 		goto reject;
 	if (cmd)
-		cmd->SCp.Message = code;
+		mesh_scsi_pointer(cmd)->Message = code;
 	switch (code) {
 	case COMMAND_COMPLETE:
 		break;
@@ -1262,7 +1264,7 @@ static void set_dma_cmds(struct mesh_state *ms, struct scsi_cmnd *cmd)
 	if (cmd) {
 		int nseg;
 
-		cmd->SCp.this_residual = scsi_bufflen(cmd);
+		mesh_scsi_pointer(cmd)->this_residual = scsi_bufflen(cmd);
 
 		nseg = scsi_dma_map(cmd);
 		BUG_ON(nseg < 0);
@@ -1592,10 +1594,13 @@ static void cmd_complete(struct mesh_state *ms)
 			break;
 		case statusing:
 			if (cmd) {
-				cmd->SCp.Status = mr->fifo;
+				struct scsi_pointer *scsi_pointer =
+					mesh_scsi_pointer(cmd);
+
+				scsi_pointer->Status = mr->fifo;
 				if (DEBUG_TARGET(cmd))
 					printk(KERN_DEBUG "mesh: status is %x\n",
-					       cmd->SCp.Status);
+					       scsi_pointer->Status);
 			}
 			ms->msgphase = msg_in;
 			break;
@@ -1837,6 +1842,7 @@ static struct scsi_host_template mesh_template = {
 	.sg_tablesize			= SG_ALL,
 	.cmd_per_lun			= 2,
 	.max_segment_size		= 65535,
+	.cmd_size			= sizeof(struct mesh_cmd_priv),
 };
 
 static int mesh_probe(struct macio_dev *mdev, const struct of_device_id *match)

drivers/scsi/mesh.h

@@ -8,6 +8,17 @@
 #ifndef _MESH_H
 #define _MESH_H
 
+struct mesh_cmd_priv {
+	struct scsi_pointer scsi_pointer;
+};
+
+static inline struct scsi_pointer *mesh_scsi_pointer(struct scsi_cmnd *cmd)
+{
+	struct mesh_cmd_priv *mcmd = scsi_cmd_priv(cmd);
+
+	return &mcmd->scsi_pointer;
+}
+
 /*
  * Registers in the MESH controller.
  */