scsi: fdomain: 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/20220218195117.25689-21-bvanassche@acm.orgReviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/fdomain.c

@@ -115,6 +115,11 @@ struct fdomain {
 	struct work_struct work;
 };
 
+static struct scsi_pointer *fdomain_scsi_pointer(struct scsi_cmnd *cmd)
+{
+	return scsi_cmd_priv(cmd);
+}
+
 static inline void fdomain_make_bus_idle(struct fdomain *fd)
 {
 	outb(0, fd->base + REG_BCTL);
@@ -263,20 +268,21 @@ static void fdomain_work(struct work_struct *work)
 	struct Scsi_Host *sh = container_of((void *)fd, struct Scsi_Host,
 					    hostdata);
 	struct scsi_cmnd *cmd = fd->cur_cmd;
+	struct scsi_pointer *scsi_pointer = fdomain_scsi_pointer(cmd);
 	unsigned long flags;
 	int status;
 	int done = 0;
 
 	spin_lock_irqsave(sh->host_lock, flags);
 
-	if (cmd->SCp.phase & in_arbitration) {
+	if (scsi_pointer->phase & in_arbitration) {
 		status = inb(fd->base + REG_ASTAT);
 		if (!(status & ASTAT_ARB)) {
 			set_host_byte(cmd, DID_BUS_BUSY);
 			fdomain_finish_cmd(fd);
 			goto out;
 		}
-		cmd->SCp.phase = in_selection;
+		scsi_pointer->phase = in_selection;
 
 		outb(ICTL_SEL | FIFO_COUNT, fd->base + REG_ICTL);
 		outb(BCTL_BUSEN | BCTL_SEL, fd->base + REG_BCTL);
@@ -285,7 +291,7 @@ static void fdomain_work(struct work_struct *work)
 		/* Stop arbitration and enable parity */
 		outb(ACTL_IRQEN | PARITY_MASK, fd->base + REG_ACTL);
 		goto out;
-	} else if (cmd->SCp.phase & in_selection) {
+	} else if (scsi_pointer->phase & in_selection) {
 		status = inb(fd->base + REG_BSTAT);
 		if (!(status & BSTAT_BSY)) {
 			/* Try again, for slow devices */
@@ -297,75 +303,75 @@ static void fdomain_work(struct work_struct *work)
 			/* Stop arbitration and enable parity */
 			outb(ACTL_IRQEN | PARITY_MASK, fd->base + REG_ACTL);
 		}
-		cmd->SCp.phase = in_other;
+		scsi_pointer->phase = in_other;
 		outb(ICTL_FIFO | ICTL_REQ | FIFO_COUNT, fd->base + REG_ICTL);
 		outb(BCTL_BUSEN, fd->base + REG_BCTL);
 		goto out;
 	}
 
-	/* cur_cmd->SCp.phase == in_other: this is the body of the routine */
+	/* fdomain_scsi_pointer(cur_cmd)->phase == in_other: this is the body of the routine */
 	status = inb(fd->base + REG_BSTAT);
 
 	if (status & BSTAT_REQ) {
 		switch (status & (BSTAT_MSG | BSTAT_CMD | BSTAT_IO)) {
 		case BSTAT_CMD:	/* COMMAND OUT */
-			outb(cmd->cmnd[cmd->SCp.sent_command++],
+			outb(cmd->cmnd[scsi_pointer->sent_command++],
 			     fd->base + REG_SCSI_DATA);
 			break;
 		case 0:	/* DATA OUT -- tmc18c50/tmc18c30 only */
-			if (fd->chip != tmc1800 && !cmd->SCp.have_data_in) {
-				cmd->SCp.have_data_in = -1;
+			if (fd->chip != tmc1800 && !scsi_pointer->have_data_in) {
+				scsi_pointer->have_data_in = -1;
 				outb(ACTL_IRQEN | ACTL_FIFOWR | ACTL_FIFOEN |
 				     PARITY_MASK, fd->base + REG_ACTL);
 			}
 			break;
 		case BSTAT_IO:	/* DATA IN -- tmc18c50/tmc18c30 only */
-			if (fd->chip != tmc1800 && !cmd->SCp.have_data_in) {
-				cmd->SCp.have_data_in = 1;
+			if (fd->chip != tmc1800 && !scsi_pointer->have_data_in) {
+				scsi_pointer->have_data_in = 1;
 				outb(ACTL_IRQEN | ACTL_FIFOEN | PARITY_MASK,
 				     fd->base + REG_ACTL);
 			}
 			break;
 		case BSTAT_CMD | BSTAT_IO:	/* STATUS IN */
-			cmd->SCp.Status = inb(fd->base + REG_SCSI_DATA);
+			scsi_pointer->Status = inb(fd->base + REG_SCSI_DATA);
 			break;
 		case BSTAT_MSG | BSTAT_CMD:	/* MESSAGE OUT */
 			outb(MESSAGE_REJECT, fd->base + REG_SCSI_DATA);
 			break;
 		case BSTAT_MSG | BSTAT_CMD | BSTAT_IO:	/* MESSAGE IN */
-			cmd->SCp.Message = inb(fd->base + REG_SCSI_DATA);
-			if (cmd->SCp.Message == COMMAND_COMPLETE)
+			scsi_pointer->Message = inb(fd->base + REG_SCSI_DATA);
+			if (scsi_pointer->Message == COMMAND_COMPLETE)
 				++done;
 			break;
 		}
 	}
 
-	if (fd->chip == tmc1800 && !cmd->SCp.have_data_in &&
-	    cmd->SCp.sent_command >= cmd->cmd_len) {
+	if (fd->chip == tmc1800 && !scsi_pointer->have_data_in &&
+	    scsi_pointer->sent_command >= cmd->cmd_len) {
 		if (cmd->sc_data_direction == DMA_TO_DEVICE) {
-			cmd->SCp.have_data_in = -1;
+			scsi_pointer->have_data_in = -1;
 			outb(ACTL_IRQEN | ACTL_FIFOWR | ACTL_FIFOEN |
 			     PARITY_MASK, fd->base + REG_ACTL);
 		} else {
-			cmd->SCp.have_data_in = 1;
+			scsi_pointer->have_data_in = 1;
 			outb(ACTL_IRQEN | ACTL_FIFOEN | PARITY_MASK,
 			     fd->base + REG_ACTL);
 		}
 	}
 
-	if (cmd->SCp.have_data_in == -1) /* DATA OUT */
+	if (scsi_pointer->have_data_in == -1) /* DATA OUT */
 		fdomain_write_data(cmd);
 
-	if (cmd->SCp.have_data_in == 1) /* DATA IN */
+	if (scsi_pointer->have_data_in == 1) /* DATA IN */
 		fdomain_read_data(cmd);
 
 	if (done) {
-		set_status_byte(cmd, cmd->SCp.Status);
+		set_status_byte(cmd, scsi_pointer->Status);
 		set_host_byte(cmd, DID_OK);
-		scsi_msg_to_host_byte(cmd, cmd->SCp.Message);
+		scsi_msg_to_host_byte(cmd, scsi_pointer->Message);
 		fdomain_finish_cmd(fd);
 	} else {
-		if (cmd->SCp.phase & disconnect) {
+		if (scsi_pointer->phase & disconnect) {
 			outb(ICTL_FIFO | ICTL_SEL | ICTL_REQ | FIFO_COUNT,
 			     fd->base + REG_ICTL);
 			outb(0, fd->base + REG_BCTL);
@@ -398,14 +404,15 @@ static irqreturn_t fdomain_irq(int irq, void *dev_id)
 
 static int fdomain_queue(struct Scsi_Host *sh, struct scsi_cmnd *cmd)
 {
+	struct scsi_pointer *scsi_pointer = fdomain_scsi_pointer(cmd);
 	struct fdomain *fd = shost_priv(cmd->device->host);
 	unsigned long flags;
 
-	cmd->SCp.Status		= 0;
-	cmd->SCp.Message	= 0;
-	cmd->SCp.have_data_in	= 0;
-	cmd->SCp.sent_command	= 0;
-	cmd->SCp.phase		= in_arbitration;
+	scsi_pointer->Status		= 0;
+	scsi_pointer->Message		= 0;
+	scsi_pointer->have_data_in	= 0;
+	scsi_pointer->sent_command	= 0;
+	scsi_pointer->phase		= in_arbitration;
 	scsi_set_resid(cmd, scsi_bufflen(cmd));
 
 	spin_lock_irqsave(sh->host_lock, flags);
@@ -440,7 +447,7 @@ static int fdomain_abort(struct scsi_cmnd *cmd)
 	spin_lock_irqsave(sh->host_lock, flags);
 
 	fdomain_make_bus_idle(fd);
-	fd->cur_cmd->SCp.phase |= aborted;
+	fdomain_scsi_pointer(fd->cur_cmd)->phase |= aborted;
 
 	/* Aborts are not done well. . . */
 	set_host_byte(fd->cur_cmd, DID_ABORT);
@@ -501,6 +508,7 @@ static struct scsi_host_template fdomain_template = {
 	.this_id		= 7,
 	.sg_tablesize		= 64,
 	.dma_boundary		= PAGE_SIZE - 1,
+	.cmd_size		= sizeof(struct scsi_pointer),
 };
 
 struct Scsi_Host *fdomain_create(int base, int irq, int this_id,