--- linux-2.5.6-pre2/drivers/scsi/hosts.h	Tue Feb 19 18:10:59 2002
+++ linux/drivers/scsi/hosts.h	Wed Mar  6 01:10:44 2002
@@ -286,6 +286,11 @@
 
     unsigned highmem_io:1;
 
+    /* Have the high level code automatically handle DMA mapping of
+       Scsi_Request->request_buffer and Scsi_Request->sense_buf. */
+    unsigned dma_map_request:1;
+    unsigned dma_map_sense:1;
+
     /*
      * Name of proc directory
      */
--- linux-2.5.6-pre2/drivers/scsi/scsi.h	Tue Feb 19 18:10:58 2002
+++ linux/drivers/scsi/scsi.h	Wed Mar  6 02:31:05 2002
@@ -734,12 +732,14 @@
 
 	struct timer_list eh_timeout;	/* Used to time out the command. */
 	void *request_buffer;		/* Actual requested buffer */
+	dma_addr_t request_dma_addr;
 
 	/* These elements define the operation we ultimately want to perform */
 	unsigned char data_cmnd[MAX_COMMAND_SIZE];
 	unsigned short old_use_sg;	/* We save  use_sg here when requesting
 					 * sense info */
 	unsigned short use_sg;	/* Number of pieces of scatter-gather */
+	unsigned short sgcnt_dma;	/* Returned by pci_map_sg. */
 	unsigned short sglist_len;	/* size of malloc'd scatter-gather list */
 	unsigned short abort_reason;	/* If the mid-level code requests an
 					 * abort, this is the reason. */
@@ -768,6 +768,7 @@
 						 * when CHECK CONDITION is
 						 * received on original command 
 						 * (auto-sense) */
+	dma_addr_t sense_dma_addr;
 
 	unsigned flags;
 
--- linux-2.5.6-pre2/drivers/scsi/scsi.c	Tue Feb 19 18:11:03 2002
+++ linux/drivers/scsi/scsi.c	Wed Mar  6 02:43:55 2002
@@ -309,6 +309,76 @@
 	return SRpnt;
 }
 
+static inline void
+scsi_unmap_dma(Scsi_Cmnd *cmd)
+{
+	const Scsi_Host_Template *template = cmd->host->hostt;
+
+	/* TODO: Simplify device drivers by having this routine rebuild
+	   any cmd->use_sg==0 request as a cmd->use_sg==1 request. */
+
+	if (template->dma_map_request) {
+		int dma_dir = scsi_to_pci_dma_dir(cmd->sc_data_direction);
+		if (cmd->use_sg)
+			pci_unmap_sg(cmd->host->pci_dev,
+				     (struct scatterlist*)cmd->request_buffer,
+				     cmd->use_sg,
+				     dma_dir);
+		else if (cmd->request_bufflen)
+			pci_unmap_single(cmd->host->pci_dev,
+					 cmd->request_dma_addr,
+					 cmd->request_bufflen,
+					 dma_dir);
+	}
+
+	if (template->dma_map_sense && cmd->sense_dma_addr)
+		pci_unmap_single(cmd->host->pci_dev,
+				 cmd->sense_dma_addr,
+				 sizeof(cmd->sense_buffer),
+				 PCI_DMA_FROMDEVICE);
+}
+
+static inline int
+scsi_map_dma(Scsi_Cmnd *cmd)
+{
+	const Scsi_Host_Template *template = cmd->host->hostt;
+
+	/* TODO: Simplify device drivers by having this routine rebuild
+	   any cmd->use_sg==0 request as a cmd->use_sg==1 request. */
+
+	if (template->dma_map_request) {
+		int dma_dir = scsi_to_pci_dma_dir(cmd->sc_data_direction);
+		if (cmd->use_sg) {
+			cmd->sgcnt_dma = pci_map_sg(cmd->host->pci_dev,
+						    (struct scatterlist*)
+						    cmd->request_buffer,
+						    cmd->use_sg,
+						    dma_dir);
+			if (cmd->sgcnt_dma <= 0)
+				return -EBUSY;
+		} else if (cmd->request_bufflen) {
+			cmd->request_dma_addr =
+				pci_map_single(cmd->host->pci_dev,
+					       cmd->request_buffer,
+					       cmd->request_bufflen,
+					       dma_dir);
+			if (!cmd->request_dma_addr)
+				return -EBUSY;
+		}
+	}
+	if (template->dma_map_sense) {
+		cmd->sense_dma_addr = pci_map_single(cmd->host->pci_dev,
+						     cmd->sense_buffer,
+						     sizeof(cmd->sense_buffer),
+						     PCI_DMA_FROMDEVICE);
+		if (!cmd->sense_dma_addr) {
+			scsi_unmap_dma(cmd);
+			return -EBUSY;
+		}
+	}
+	return 0;
+}
+
 /*
  * Function:    scsi_release_request
  *
@@ -706,6 +776,7 @@
 		 * length exceeds what the host adapter can handle.
 		 */
 		if (CDB_SIZE(SCpnt) <= SCpnt->host->max_cmd_len) {
+			scsi_map_dma(SCpnt);
 			spin_lock_irqsave(host->host_lock, flags);
 			rtn = host->hostt->queuecommand(SCpnt, scsi_done);
 			spin_unlock_irqrestore(host->host_lock, flags);
@@ -1146,6 +1217,7 @@
 		SCSI_LOG_MLCOMPLETE(1, printk("Ignoring completion of %p due to timeout status", SCpnt));
 		return;
 	}
+	scsi_unmap_dma(SCpnt);
 	spin_lock_irqsave(&scsi_bhqueue_lock, flags);
 
 	SCpnt->serial_number_at_timeout = 0;