Only the atari_scsi and sun3_scsi drivers define DMA_MIN_SIZE.
Both drivers also define NCR5380_dma_xfer_len, which means
DMA_MIN_SIZE can be removed from the core driver.
This removes another discrepancy between the two core drivers.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
                                        d = cmd->SCp.ptr;
                                }
                                /* this command setup for dma yet? */
-                               if ((count >= DMA_MIN_SIZE) && (sun3_dma_setup_done != cmd)) {
-                                       if (cmd->request->cmd_type == REQ_TYPE_FS) {
-                                               sun3scsi_dma_setup(instance, d, count,
-                                                                  rq_data_dir(cmd->request));
-                                               sun3_dma_setup_done = cmd;
-                                       }
+                               if (sun3_dma_setup_done != cmd &&
+                                   sun3scsi_dma_xfer_len(count, cmd) > 0) {
+                                       sun3scsi_dma_setup(instance, d, count,
+                                                          rq_data_dir(cmd->request));
+                                       sun3_dma_setup_done = cmd;
                                }
 #ifdef SUN3_SCSI_VME
                                dregs->csr |= CSR_INTR;
 #endif
                                        transfersize = NCR5380_dma_xfer_len(instance, cmd, phase);
 
-                               if (transfersize >= DMA_MIN_SIZE) {
+                               if (transfersize > 0) {
                                        len = transfersize;
                                        cmd->SCp.phase = phase;
                                        if (NCR5380_transfer_dma(instance, &phase,
                        d = tmp->SCp.ptr;
                }
                /* setup this command for dma if not already */
-               if ((count >= DMA_MIN_SIZE) && (sun3_dma_setup_done != tmp)) {
+               if (sun3_dma_setup_done != tmp &&
+                   sun3scsi_dma_xfer_len(count, tmp) > 0) {
                        sun3scsi_dma_setup(instance, d, count,
                                           rq_data_dir(tmp->request));
                        sun3_dma_setup_done = tmp;
 
 
 #include <scsi/scsi_host.h>
 
+#define DMA_MIN_SIZE                    32
+
 /* Definitions for the core NCR5380 driver. */
 
 #define SUPPORT_TAGS
 #define MAX_TAGS                        32
-#define DMA_MIN_SIZE                    32
 
 #define NCR5380_implementation_fields   /* none */
 
 {
        unsigned long   possible_len, limit;
 
+       if (wanted_len < DMA_MIN_SIZE)
+               return 0;
+
        if (IS_A_TT())
                /* TT SCSI DMA can transfer arbitrary #bytes */
                return wanted_len;
 
 #include <scsi/scsi_host.h>
 #include "sun3_scsi.h"
 
-/* Definitions for the core NCR5380 driver. */
-
-/* #define SUPPORT_TAGS */
 /* minimum number of bytes to do dma on */
 #define DMA_MIN_SIZE                    129
 
+/* Definitions for the core NCR5380 driver. */
+
+/* #define SUPPORT_TAGS */
 /* #define MAX_TAGS                     32 */
 
 #define NCR5380_implementation_fields   /* none */
 #define NCR5380_dma_residual(instance) \
         sun3scsi_dma_residual(instance)
 #define NCR5380_dma_xfer_len(instance, cmd, phase) \
-        sun3scsi_dma_xfer_len(cmd->SCp.this_residual, cmd, !((phase) & SR_IO))
+        sun3scsi_dma_xfer_len(cmd->SCp.this_residual, cmd)
 
 #define NCR5380_acquire_dma_irq(instance)    (1)
 #define NCR5380_release_dma_irq(instance)
        return last_residual;
 }
 
-static inline unsigned long sun3scsi_dma_xfer_len(unsigned long wanted,
-                                                 struct scsi_cmnd *cmd,
-                                                 int write_flag)
+static inline unsigned long sun3scsi_dma_xfer_len(unsigned long wanted_len,
+                                                  struct scsi_cmnd *cmd)
 {
-       if (cmd->request->cmd_type == REQ_TYPE_FS)
-               return wanted;
-       else
+       if (wanted_len < DMA_MIN_SIZE || cmd->request->cmd_type != REQ_TYPE_FS)
                return 0;
+
+       return wanted_len;
 }
 
 static inline int sun3scsi_dma_start(unsigned long count, unsigned char *data)