[ide] add sg_init_one() helper and teach ide about it

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

arch/cris/arch-v10/drivers/ide.c

@@ -30,6 +30,7 @@
 #include <linux/hdreg.h>
 #include <linux/ide.h>
 #include <linux/init.h>
+#include <linux/scatterlist.h>
 
 #include <asm/io.h>
 #include <asm/arch/svinto.h>
@@ -624,12 +625,7 @@ static int e100_ide_build_dmatable (ide_drive_t *drive)
 	ata_tot_size = 0;
 
 	if (HWGROUP(drive)->rq->flags & REQ_DRIVE_TASKFILE) {
-		u8 *virt_addr = rq->buffer;
-		int sector_count = rq->nr_sectors;
-		memset(&sg[0], 0, sizeof(*sg));
-		sg[0].page = virt_to_page(virt_addr);
-		sg[0].offset = offset_in_page(virt_addr);
-		sg[0].length =  sector_count  * SECTOR_SIZE;
+		sg_init_one(&sg[0], rq->buffer, rq->nr_sectors * SECTOR_SIZE);
 		hwif->sg_nents = i = 1;
 	}
 	else

drivers/ide/arm/icside.c

@@ -16,6 +16,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/device.h>
 #include <linux/init.h>
+#include <linux/scatterlist.h>
 
 #include <asm/dma.h>
 #include <asm/ecard.h>
@@ -223,10 +224,7 @@ static void icside_build_sglist(ide_drive_t *drive, struct request *rq)
 		else
 			hwif->sg_dma_direction = DMA_FROM_DEVICE;
 
-		memset(sg, 0, sizeof(*sg));
-		sg->page   = virt_to_page(rq->buffer);
-		sg->offset = offset_in_page(rq->buffer);
-		sg->length = rq->nr_sectors * SECTOR_SIZE;
+		sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
 		nents = 1;
 	} else {
 		nents = blk_rq_map_sg(drive->queue, rq, sg);

drivers/ide/ide-dma.c

@@ -85,6 +85,7 @@
 #include <linux/init.h>
 #include <linux/ide.h>
 #include <linux/delay.h>
+#include <linux/scatterlist.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -253,18 +254,12 @@ int ide_raw_build_sglist(ide_drive_t *drive, struct request *rq)
 #else
 	while (sector_count > 128) {
 #endif
-		memset(&sg[nents], 0, sizeof(*sg));
-		sg[nents].page = virt_to_page(virt_addr);
-		sg[nents].offset = offset_in_page(virt_addr);
-		sg[nents].length = 128  * SECTOR_SIZE;
+		sg_init_one(&sg[nents], virt_addr, 128 * SECTOR_SIZE);
 		nents++;
 		virt_addr = virt_addr + (128 * SECTOR_SIZE);
 		sector_count -= 128;
 	}
-	memset(&sg[nents], 0, sizeof(*sg));
-	sg[nents].page = virt_to_page(virt_addr);
-	sg[nents].offset = offset_in_page(virt_addr);
-	sg[nents].length =  sector_count  * SECTOR_SIZE;
+	sg_init_one(&sg[nents], virt_addr, sector_count * SECTOR_SIZE);
 	nents++;
 
 	return pci_map_sg(hwif->pci_dev, sg, nents, hwif->sg_dma_direction);

drivers/ide/ppc/pmac.c

@@ -34,6 +34,7 @@
 #include <linux/pci.h>
 #include <linux/adb.h>
 #include <linux/pmu.h>
+#include <linux/scatterlist.h>
 
 #include <asm/prom.h>
 #include <asm/io.h>
@@ -1604,18 +1605,12 @@ pmac_ide_raw_build_sglist(ide_drive_t *drive, struct request *rq)
 		pmif->sg_dma_direction = PCI_DMA_FROMDEVICE;
 	
 	if (sector_count > 128) {
-		memset(&sg[nents], 0, sizeof(*sg));
-		sg[nents].page = virt_to_page(virt_addr);
-		sg[nents].offset = offset_in_page(virt_addr);
-		sg[nents].length = 128  * SECTOR_SIZE;
+		sg_init_one(&sg[nents], virt_addr, 128 * SECTOR_SIZE);
 		nents++;
 		virt_addr = virt_addr + (128 * SECTOR_SIZE);
 		sector_count -= 128;
 	}
-	memset(&sg[nents], 0, sizeof(*sg));
-	sg[nents].page = virt_to_page(virt_addr);
-	sg[nents].offset = offset_in_page(virt_addr);
-	sg[nents].length =  sector_count  * SECTOR_SIZE;
+	sg_init_one(&sg[nents], virt_addr, sector_count * SECTOR_SIZE);
 	nents++;
    
 	return pci_map_sg(hwif->pci_dev, sg, nents, pmif->sg_dma_direction);

include/linux/scatterlist.h

+#ifndef _LINUX_SCATTERLIST_H
+#define _LINUX_SCATTERLIST_H
+
+static inline void sg_init_one(struct scatterlist *sg,
+			       u8 *buf, unsigned int buflen)
+{
+	memset(sg, 0, sizeof(*sg));
+
+	sg->page = virt_to_page(buf);
+	sg->offset = offset_in_page(buf);
+	sg->length = buflen;
+}
+
+#endif /* _LINUX_SCATTERLIST_H */