[SCSI] arm: convert to accessors and !use_sg cleanup

 - convert to accessors and !use_sg cleanup
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/arm/acornscsi.c

@@ -1790,7 +1790,7 @@ int acornscsi_starttransfer(AS_Host *host)
 	return 0;
     }
 
-    residual = host->SCpnt->request_bufflen - host->scsi.SCp.scsi_xferred;
+    residual = scsi_bufflen(host->SCpnt) - host->scsi.SCp.scsi_xferred;
 
     sbic_arm_write(host->scsi.io_port, SBIC_SYNCHTRANSFER, host->device[host->SCpnt->device->id].sync_xfer);
     sbic_arm_writenext(host->scsi.io_port, residual >> 16);
@@ -2270,7 +2270,7 @@ intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
 	case 0x4b:			/* -> PHASE_STATUSIN				*/
 	case 0x8b:			/* -> PHASE_STATUSIN				*/
 	    /* DATA IN -> STATUS */
-	    host->scsi.SCp.scsi_xferred = host->SCpnt->request_bufflen -
+	    host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
 					  acornscsi_sbic_xfcount(host);
 	    acornscsi_dma_stop(host);
 	    acornscsi_readstatusbyte(host);
@@ -2281,7 +2281,7 @@ intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
 	case 0x4e:			/* -> PHASE_MSGOUT				*/
 	case 0x8e:			/* -> PHASE_MSGOUT				*/
 	    /* DATA IN -> MESSAGE OUT */
-	    host->scsi.SCp.scsi_xferred = host->SCpnt->request_bufflen -
+	    host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
 					  acornscsi_sbic_xfcount(host);
 	    acornscsi_dma_stop(host);
 	    acornscsi_sendmessage(host);
@@ -2291,7 +2291,7 @@ intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
 	case 0x4f:			/* message in					*/
 	case 0x8f:			/* message in					*/
 	    /* DATA IN -> MESSAGE IN */
-	    host->scsi.SCp.scsi_xferred = host->SCpnt->request_bufflen -
+	    host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
 					  acornscsi_sbic_xfcount(host);
 	    acornscsi_dma_stop(host);
 	    acornscsi_message(host);	/* -> PHASE_MSGIN, PHASE_DISCONNECT		*/
@@ -2319,7 +2319,7 @@ intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
 	case 0x4b:			/* -> PHASE_STATUSIN				*/
 	case 0x8b:			/* -> PHASE_STATUSIN				*/
 	    /* DATA OUT -> STATUS */
-	    host->scsi.SCp.scsi_xferred = host->SCpnt->request_bufflen -
+	    host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
 					  acornscsi_sbic_xfcount(host);
 	    acornscsi_dma_stop(host);
 	    acornscsi_dma_adjust(host);
@@ -2331,7 +2331,7 @@ intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
 	case 0x4e:			/* -> PHASE_MSGOUT				*/
 	case 0x8e:			/* -> PHASE_MSGOUT				*/
 	    /* DATA OUT -> MESSAGE OUT */
-	    host->scsi.SCp.scsi_xferred = host->SCpnt->request_bufflen -
+	    host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
 					  acornscsi_sbic_xfcount(host);
 	    acornscsi_dma_stop(host);
 	    acornscsi_dma_adjust(host);
@@ -2342,7 +2342,7 @@ intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
 	case 0x4f:			/* message in					*/
 	case 0x8f:			/* message in					*/
 	    /* DATA OUT -> MESSAGE IN */
-	    host->scsi.SCp.scsi_xferred = host->SCpnt->request_bufflen -
+	    host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
 					  acornscsi_sbic_xfcount(host);
 	    acornscsi_dma_stop(host);
 	    acornscsi_dma_adjust(host);

drivers/scsi/arm/scsi.h

@@ -18,17 +18,32 @@
  * The scatter-gather list handling.  This contains all
  * the yucky stuff that needs to be fixed properly.
  */
+
+/*
+ * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max
+ * entries of uninitialized memory. SCp is from scsi-ml and has a valid
+ * (possibly chained) sg-list
+ */
 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
 {
 	int bufs = SCp->buffers_residual;
 
+	/* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().
+	 * and to remove this BUG_ON. Use min() in-its-place
+	 */
 	BUG_ON(bufs + 1 > max);
 
 	sg_set_buf(sg, SCp->ptr, SCp->this_residual);
 
-	if (bufs)
-		memcpy(sg + 1, SCp->buffer + 1,
-		       sizeof(struct scatterlist) * bufs);
+	if (bufs) {
+		struct scatterlist *src_sg;
+		unsigned i;
+
+		for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
+			*(++sg) = *src_sg;
+		sg_mark_end(sg);
+	}
+
 	return bufs + 1;
 }
 
@@ -36,7 +51,7 @@ static inline int next_SCp(struct scsi_pointer *SCp)
 {
 	int ret = SCp->buffers_residual;
 	if (ret) {
-		SCp->buffer++;
+		SCp->buffer = sg_next(SCp->buffer);
 		SCp->buffers_residual--;
 		SCp->ptr = sg_virt(SCp->buffer);
 		SCp->this_residual = SCp->buffer->length;
@@ -68,46 +83,46 @@ static inline void init_SCp(struct scsi_cmnd *SCpnt)
 {
 	memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));
 
-	if (SCpnt->use_sg) {
+	if (scsi_bufflen(SCpnt)) {
 		unsigned long len = 0;
-		int buf;
 
-		SCpnt->SCp.buffer = (struct scatterlist *) SCpnt->request_buffer;
-		SCpnt->SCp.buffers_residual = SCpnt->use_sg - 1;
+		SCpnt->SCp.buffer = scsi_sglist(SCpnt);
+		SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
 		SCpnt->SCp.ptr = sg_virt(SCpnt->SCp.buffer);
 		SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
-		SCpnt->SCp.phase = SCpnt->request_bufflen;
+		SCpnt->SCp.phase = scsi_bufflen(SCpnt);
 
 #ifdef BELT_AND_BRACES
-		/*
-		 * Calculate correct buffer length.  Some commands
-		 * come in with the wrong request_bufflen.
-		 */
-		for (buf = 0; buf <= SCpnt->SCp.buffers_residual; buf++)
-			len += SCpnt->SCp.buffer[buf].length;
-
-		if (SCpnt->request_bufflen != len)
-			printk(KERN_WARNING "scsi%d.%c: bad request buffer "
-			       "length %d, should be %ld\n", SCpnt->device->host->host_no,
-			       '0' + SCpnt->device->id, SCpnt->request_bufflen, len);
-		SCpnt->request_bufflen = len;
+		{	/*
+			 * Calculate correct buffer length.  Some commands
+			 * come in with the wrong scsi_bufflen.
+			 */
+			struct scatterlist *sg;
+			unsigned i, sg_count = scsi_sg_count(SCpnt);
+
+			scsi_for_each_sg(SCpnt, sg, sg_count, i)
+				len += sg->length;
+
+			if (scsi_bufflen(SCpnt) != len) {
+				printk(KERN_WARNING
+				       "scsi%d.%c: bad request buffer "
+				       "length %d, should be %ld\n",
+					SCpnt->device->host->host_no,
+					'0' + SCpnt->device->id,
+					scsi_bufflen(SCpnt), len);
+				/*
+				 * FIXME: Totaly naive fixup. We should abort
+				 * with error
+				 */
+				SCpnt->SCp.phase =
+					min_t(unsigned long, len,
+					      scsi_bufflen(SCpnt));
+			}
+		}
 #endif
 	} else {
-		SCpnt->SCp.ptr = (unsigned char *)SCpnt->request_buffer;
-		SCpnt->SCp.this_residual = SCpnt->request_bufflen;
-		SCpnt->SCp.phase = SCpnt->request_bufflen;
-	}
-
-	/*
-	 * If the upper SCSI layers pass a buffer, but zero length,
-	 * we aren't interested in the buffer pointer.
-	 */
-	if (SCpnt->SCp.this_residual == 0 && SCpnt->SCp.ptr) {
-#if 0 //def BELT_AND_BRACES
-		printk(KERN_WARNING "scsi%d.%c: zero length buffer passed for "
-		       "command ", SCpnt->host->host_no, '0' + SCpnt->target);
-		__scsi_print_command(SCpnt->cmnd);
-#endif
 		SCpnt->SCp.ptr = NULL;
+		SCpnt->SCp.this_residual = 0;
+		SCpnt->SCp.phase = 0;
 	}
 }