diff --git a/drivers/scsi/a2091.c b/drivers/scsi/a2091.c
index 95584059863bf95142b3de592a452b67b3a610e6..308541ff85cf9ff127a118696bc2b62d0d6d255e 100644
--- a/drivers/scsi/a2091.c
+++ b/drivers/scsi/a2091.c
@@ -22,17 +22,15 @@
 #include <linux/stat.h>
 
 
-#define DMA(ptr)	((a2091_scsiregs *)((ptr)->base))
-
 static int a2091_release(struct Scsi_Host *instance);
 
-static irqreturn_t a2091_intr(int irq, void *_instance)
+static irqreturn_t a2091_intr(int irq, void *data)
 {
+	struct Scsi_Host *instance = data;
+	a2091_scsiregs *regs = (a2091_scsiregs *)(instance->base);
+	unsigned int status = regs->ISTR;
 	unsigned long flags;
-	unsigned int status;
-	struct Scsi_Host *instance = (struct Scsi_Host *)_instance;
 
-	status = DMA(instance)->ISTR;
 	if (!(status & (ISTR_INT_F | ISTR_INT_P)) || !(status & ISTR_INTS))
 		return IRQ_NONE;
 
@@ -46,6 +44,7 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
 {
 	struct Scsi_Host *instance = cmd->device->host;
 	struct WD33C93_hostdata *hdata = shost_priv(instance);
+	a2091_scsiregs *regs = (a2091_scsiregs *)(instance->base);
 	unsigned short cntr = CNTR_PDMD | CNTR_INTEN;
 	unsigned long addr = virt_to_bus(cmd->SCp.ptr);
 
@@ -87,10 +86,10 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
 	/* remember direction */
 	hdata->dma_dir = dir_in;
 
-	DMA(cmd->device->host)->CNTR = cntr;
+	regs->CNTR = cntr;
 
 	/* setup DMA *physical* address */
-	DMA(cmd->device->host)->ACR = addr;
+	regs->ACR = addr;
 
 	if (dir_in) {
 		/* invalidate any cache */
@@ -100,7 +99,7 @@ static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
 		cache_push(addr, cmd->SCp.this_residual);
 	}
 	/* start DMA */
-	DMA(cmd->device->host)->ST_DMA = 1;
+	regs->ST_DMA = 1;
 
 	/* return success */
 	return 0;
@@ -110,6 +109,7 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
 		     int status)
 {
 	struct WD33C93_hostdata *hdata = shost_priv(instance);
+	a2091_scsiregs *regs = (a2091_scsiregs *)(instance->base);
 
 	/* disable SCSI interrupts */
 	unsigned short cntr = CNTR_PDMD;
@@ -118,23 +118,23 @@ static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
 		cntr |= CNTR_DDIR;
 
 	/* disable SCSI interrupts */
-	DMA(instance)->CNTR = cntr;
+	regs->CNTR = cntr;
 
 	/* flush if we were reading */
 	if (hdata->dma_dir) {
-		DMA(instance)->FLUSH = 1;
-		while (!(DMA(instance)->ISTR & ISTR_FE_FLG))
+		regs->FLUSH = 1;
+		while (!(regs->ISTR & ISTR_FE_FLG))
 			;
 	}
 
 	/* clear a possible interrupt */
-	DMA(instance)->CINT = 1;
+	regs->CINT = 1;
 
 	/* stop DMA */
-	DMA(instance)->SP_DMA = 1;
+	regs->SP_DMA = 1;
 
 	/* restore the CONTROL bits (minus the direction flag) */
-	DMA(instance)->CNTR = CNTR_PDMD | CNTR_INTEN;
+	regs->CNTR = CNTR_PDMD | CNTR_INTEN;
 
 	/* copy from a bounce buffer, if necessary */
 	if (status && hdata->dma_bounce_buffer) {
@@ -153,7 +153,8 @@ static int __init a2091_detect(struct scsi_host_template *tpnt)
 	struct Scsi_Host *instance;
 	unsigned long address;
 	struct zorro_dev *z = NULL;
-	wd33c93_regs regs;
+	wd33c93_regs wdregs;
+	a2091_scsiregs *regs;
 	struct WD33C93_hostdata *hdata;
 	int num_a2091 = 0;
 
@@ -178,19 +179,20 @@ static int __init a2091_detect(struct scsi_host_template *tpnt)
 		instance->base = ZTWO_VADDR(address);
 		instance->irq = IRQ_AMIGA_PORTS;
 		instance->unique_id = z->slotaddr;
-		DMA(instance)->DAWR = DAWR_A2091;
-		regs.SASR = &(DMA(instance)->SASR);
-		regs.SCMD = &(DMA(instance)->SCMD);
+		regs = (a2091_scsiregs *)(instance->base);
+		regs->DAWR = DAWR_A2091;
+		wdregs.SASR = &regs->SASR;
+		wdregs.SCMD = &regs->SCMD;
 		hdata = shost_priv(instance);
 		hdata->no_sync = 0xff;
 		hdata->fast = 0;
 		hdata->dma_mode = CTRL_DMA;
-		wd33c93_init(instance, regs, dma_setup, dma_stop,
+		wd33c93_init(instance, wdregs, dma_setup, dma_stop,
 			     WD33C93_FS_8_10);
 		if (request_irq(IRQ_AMIGA_PORTS, a2091_intr, IRQF_SHARED,
 				"A2091 SCSI", instance))
 			goto unregister;
-		DMA(instance)->CNTR = CNTR_PDMD | CNTR_INTEN;
+		regs->CNTR = CNTR_PDMD | CNTR_INTEN;
 		num_a2091++;
 		continue;
 
@@ -241,7 +243,9 @@ static struct scsi_host_template driver_template = {
 static int a2091_release(struct Scsi_Host *instance)
 {
 #ifdef MODULE
-	DMA(instance)->CNTR = 0;
+	a2091_scsiregs *regs = (a2091_scsiregs *)(instance->base);
+
+	regs->CNTR = 0;
 	release_mem_region(ZTWO_PADDR(instance->base), 256);
 	free_irq(IRQ_AMIGA_PORTS, instance);
 #endif