scsi: wd719x: Stop using the SCSI pointer

Move the DMA handle into the per-command private data 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/20220218195117.25689-47-bvanassche@acm.org
Cc: Ondrej Zary <linux@zary.sk>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
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/wd719x.c

@@ -196,7 +196,7 @@ static void wd719x_finish_cmd(struct wd719x_scb *scb, int result)
 	dma_unmap_single(&wd->pdev->dev, scb->phys,
 			sizeof(struct wd719x_scb), DMA_BIDIRECTIONAL);
 	scsi_dma_unmap(cmd);
-	dma_unmap_single(&wd->pdev->dev, cmd->SCp.dma_handle,
+	dma_unmap_single(&wd->pdev->dev, scb->dma_handle,
 			 SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
 
 	cmd->result = result << 16;
@@ -229,11 +229,11 @@ static int wd719x_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *cmd)
 
 	/* map sense buffer */
 	scb->sense_buf_length = SCSI_SENSE_BUFFERSIZE;
-	cmd->SCp.dma_handle = dma_map_single(&wd->pdev->dev, cmd->sense_buffer,
-			SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
-	if (dma_mapping_error(&wd->pdev->dev, cmd->SCp.dma_handle))
+	scb->dma_handle = dma_map_single(&wd->pdev->dev, cmd->sense_buffer,
+			       SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
+	if (dma_mapping_error(&wd->pdev->dev, scb->dma_handle))
 		goto out_unmap_scb;
-	scb->sense_buf = cpu_to_le32(cmd->SCp.dma_handle);
+	scb->sense_buf = cpu_to_le32(scb->dma_handle);
 
 	/* request autosense */
 	scb->SCB_options |= WD719X_SCB_FLAGS_AUTO_REQUEST_SENSE;
@@ -288,7 +288,7 @@ static int wd719x_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *cmd)
 	return 0;
 
 out_unmap_sense:
-	dma_unmap_single(&wd->pdev->dev, cmd->SCp.dma_handle,
+	dma_unmap_single(&wd->pdev->dev, scb->dma_handle,
 			 SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
 out_unmap_scb:
 	dma_unmap_single(&wd->pdev->dev, scb->phys, sizeof(*scb),

drivers/scsi/wd719x.h

@@ -56,6 +56,7 @@ struct wd719x_scb {
 	u8 flags[2];	/* 62-63 SCB specific flags (local to each thread) */
 	/* everything below is for driver use (not used by card) */
 	dma_addr_t phys;	/* bus address of the SCB */
+	dma_addr_t dma_handle;
 	struct scsi_cmnd *cmd;	/* a copy of the pointer we were passed */
 	struct list_head list;
 	struct wd719x_sglist sg_list[WD719X_SG] __aligned(8); /* SG list */