[MM]: Add and use offset_in_page() convenience macro.

Based upon patches from Yoshfuji Hideaki <yoshfuji@linux-ipv6.org>

Documentation/DMA-mapping.txt

@@ -689,7 +689,7 @@ portably refer to any piece of memory.  If you have a cpu pointer
 and offset using something like this:
 
 	struct page *page = virt_to_page(ptr);
-	unsigned long offset = ((unsigned long)ptr & ~PAGE_MASK);
+	unsigned long offset = offset_in_page(ptr);
 
 Here are the interfaces:
 

crypto/hmac.c

@@ -26,7 +26,7 @@ static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
 	struct scatterlist tmp;
 	
 	tmp.page = virt_to_page(key);
-	tmp.offset = ((long)key & ~PAGE_MASK);
+	tmp.offset = offset_in_page(key);
 	tmp.length = keylen;
 	crypto_digest_digest(tfm, &tmp, 1, key);
 		
@@ -71,7 +71,7 @@ void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
 		ipad[i] ^= 0x36;
 
 	tmp.page = virt_to_page(ipad);
-	tmp.offset = ((long)ipad & ~PAGE_MASK);
+	tmp.offset = offset_in_page(ipad);
 	tmp.length = crypto_tfm_alg_blocksize(tfm);
 	
 	crypto_digest_init(tfm);
@@ -105,14 +105,14 @@ void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
 		opad[i] ^= 0x5c;
 
 	tmp.page = virt_to_page(opad);
-	tmp.offset = ((long)opad & ~PAGE_MASK);
+	tmp.offset = offset_in_page(opad);
 	tmp.length = crypto_tfm_alg_blocksize(tfm);
 
 	crypto_digest_init(tfm);
 	crypto_digest_update(tfm, &tmp, 1);
 	
 	tmp.page = virt_to_page(out);
-	tmp.offset = ((long)out & ~PAGE_MASK);
+	tmp.offset = offset_in_page(out);
 	tmp.length = crypto_tfm_alg_digestsize(tfm);
 	
 	crypto_digest_update(tfm, &tmp, 1);

drivers/block/cryptoloop.c

@@ -162,11 +162,11 @@ cryptoloop_transfer_cbc(struct loop_device *lo, int cmd, char *raw_buf,
 		iv[0] = cpu_to_le32(IV & 0xffffffff);
 
 		sg_in.page = virt_to_page(in);
-		sg_in.offset = (unsigned long)in & ~PAGE_MASK;
+		sg_in.offset = offset_in_page(in);
 		sg_in.length = sz;
 
 		sg_out.page = virt_to_page(out);
-		sg_out.offset = (unsigned long)out & ~PAGE_MASK;
+		sg_out.offset = offset_in_page(out);
 		sg_out.length = sz;
 
 		encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);

drivers/ide/arm/icside.c

@@ -233,7 +233,7 @@ static void ide_build_sglist(ide_drive_t *drive, struct request *rq)
 
 		memset(sg, 0, sizeof(*sg));
 		sg->page   = virt_to_page(rq->buffer);
-		sg->offset = ((unsigned long)rq->buffer) & ~PAGE_MASK;
+		sg->offset = offset_in_page(rq->buffer);
 		sg->length = rq->nr_sectors * SECTOR_SIZE;
 		nents = 1;
 	} else {

drivers/ide/ide-dma.c

@@ -255,7 +255,7 @@ static int ide_raw_build_sglist (ide_drive_t *drive, struct request *rq)
 #endif
 		memset(&sg[nents], 0, sizeof(*sg));
 		sg[nents].page = virt_to_page(virt_addr);
-		sg[nents].offset = (unsigned long) virt_addr & ~PAGE_MASK;
+		sg[nents].offset = offset_in_page(virt_addr);
 		sg[nents].length = 128  * SECTOR_SIZE;
 		nents++;
 		virt_addr = virt_addr + (128 * SECTOR_SIZE);
@@ -263,7 +263,7 @@ static int ide_raw_build_sglist (ide_drive_t *drive, struct request *rq)
 	}
 	memset(&sg[nents], 0, sizeof(*sg));
 	sg[nents].page = virt_to_page(virt_addr);
-	sg[nents].offset = (unsigned long) virt_addr & ~PAGE_MASK;
+	sg[nents].offset = offset_in_page(virt_addr);
 	sg[nents].length =  sector_count  * SECTOR_SIZE;
 	nents++;
 

drivers/ide/ppc/pmac.c

@@ -971,7 +971,7 @@ pmac_ide_raw_build_sglist(ide_drive_t *drive, struct request *rq)
 	if (sector_count > 127) {
 		memset(&sg[nents], 0, sizeof(*sg));
 		sg[nents].page = virt_to_page(virt_addr);
-		sg[nents].offset = (unsigned long) virt_addr & ~PAGE_MASK;
+		sg[nents].offset = offset_in_page(virt_addr);
 		sg[nents].length = 127  * SECTOR_SIZE;
 		nents++;
 		virt_addr = virt_addr + (127 * SECTOR_SIZE);
@@ -979,7 +979,7 @@ pmac_ide_raw_build_sglist(ide_drive_t *drive, struct request *rq)
 	}
 	memset(&sg[nents], 0, sizeof(*sg));
 	sg[nents].page = virt_to_page(virt_addr);
-	sg[nents].offset = (unsigned long) virt_addr & ~PAGE_MASK;
+	sg[nents].offset = offset_in_page(virt_addr);
 	sg[nents].length =  sector_count  * SECTOR_SIZE;
 	nents++;
    

drivers/net/acenic.c

@@ -1960,7 +1960,7 @@ static void ace_load_std_rx_ring(struct ace_private *ap, int nr_bufs)
 		 */
 		skb_reserve(skb, 2 + 16);
 		mapping = pci_map_page(ap->pdev, virt_to_page(skb->data),
-				       ((unsigned long)skb->data & ~PAGE_MASK),
+				       offset_in_page(skb->data),
 				       ACE_STD_BUFSIZE - (2 + 16),
 				       PCI_DMA_FROMDEVICE);
 		ap->skb->rx_std_skbuff[idx].skb = skb;
@@ -2026,7 +2026,7 @@ static void ace_load_mini_rx_ring(struct ace_private *ap, int nr_bufs)
 		 */
 		skb_reserve(skb, 2 + 16);
 		mapping = pci_map_page(ap->pdev, virt_to_page(skb->data),
-				       ((unsigned long)skb->data & ~PAGE_MASK),
+				       offset_in_page(skb->data),
 				       ACE_MINI_BUFSIZE - (2 + 16),
 				       PCI_DMA_FROMDEVICE);
 		ap->skb->rx_mini_skbuff[idx].skb = skb;
@@ -2087,7 +2087,7 @@ static void ace_load_jumbo_rx_ring(struct ace_private *ap, int nr_bufs)
 		 */
 		skb_reserve(skb, 2 + 16);
 		mapping = pci_map_page(ap->pdev, virt_to_page(skb->data),
-				       ((unsigned long)skb->data & ~PAGE_MASK),
+				       offset_in_page(skb->data),
 				       ACE_JUMBO_BUFSIZE - (2 + 16),
 				       PCI_DMA_FROMDEVICE);
 		ap->skb->rx_jumbo_skbuff[idx].skb = skb;
@@ -2743,7 +2743,7 @@ ace_map_tx_skb(struct ace_private *ap, struct sk_buff *skb,
 	struct tx_ring_info *info;
 
 	mapping = pci_map_page(ap->pdev, virt_to_page(skb->data),
-			       ((unsigned long) skb->data & ~PAGE_MASK),
+			       offset_in_page(skb->data),
 			       skb->len, PCI_DMA_TODEVICE);
 
 	info = ap->skb->tx_skbuff + idx;

drivers/net/sk98lin/skge.c

@@ -2142,7 +2142,7 @@ struct sk_buff	*pMessage)	/* pointer to send-message              */
 	*/
 	PhysAddr = (SK_U64) pci_map_page(pAC->PciDev,
 					virt_to_page(pMessage->data),
-					((unsigned long) pMessage->data & ~PAGE_MASK),
+					offset_in_page(pMessage->data),
 					pMessage->len,
 					PCI_DMA_TODEVICE);
 	pTxd->VDataLow  = (SK_U32) (PhysAddr & 0xffffffff);
@@ -2259,7 +2259,7 @@ struct sk_buff	*pMessage)	/* pointer to send-message              */
 	*/
 	PhysAddr = (SK_U64) pci_map_page(pAC->PciDev,
 			virt_to_page(pMessage->data),
-			((unsigned long) pMessage->data & ~PAGE_MASK),
+			offset_in_page(pMessage->data),
 			skb_headlen(pMessage),
 			PCI_DMA_TODEVICE);
 
@@ -2518,8 +2518,7 @@ SK_U64		PhysAddr;	/* physical address of a rx buffer */
 	Length = pAC->RxBufSize;
 	PhysAddr = (SK_U64) pci_map_page(pAC->PciDev,
 		virt_to_page(pMsgBlock->data),
-		((unsigned long) pMsgBlock->data &
-		~PAGE_MASK),
+		offset_in_page(pMsgBlock->data),
 		pAC->RxBufSize - 2,
 		PCI_DMA_FROMDEVICE);
 

drivers/net/sungem.c

@@ -725,8 +725,7 @@ static void gem_rx(struct gem *gp)
 			skb_put(new_skb, (ETH_FRAME_LEN + RX_OFFSET));
 			rxd->buffer = cpu_to_le64(pci_map_page(gp->pdev,
 							       virt_to_page(new_skb->data),
-							       ((unsigned long) new_skb->data &
-								~PAGE_MASK),
+							       offset_in_page(new_skb->data),
 							       RX_BUF_ALLOC_SIZE(gp),
 							       PCI_DMA_FROMDEVICE));
 			skb_reserve(new_skb, RX_OFFSET);
@@ -873,8 +872,7 @@ static int gem_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		len = skb->len;
 		mapping = pci_map_page(gp->pdev,
 				       virt_to_page(skb->data),
-				       ((unsigned long) skb->data &
-					~PAGE_MASK),
+				       offset_in_page(skb->data),
 				       len, PCI_DMA_TODEVICE);
 		ctrl |= TXDCTRL_SOF | TXDCTRL_EOF | len;
 		if (gem_intme(entry))
@@ -898,7 +896,7 @@ static int gem_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		 */
 		first_len = skb_headlen(skb);
 		first_mapping = pci_map_page(gp->pdev, virt_to_page(skb->data),
-					     ((unsigned long) skb->data & ~PAGE_MASK),
+					     offset_in_page(skb->data),
 					     first_len, PCI_DMA_TODEVICE);
 		entry = NEXT_TX(entry);
 
@@ -1464,8 +1462,7 @@ static void gem_init_rings(struct gem *gp)
 		skb_put(skb, (ETH_FRAME_LEN + RX_OFFSET));
 		dma_addr = pci_map_page(gp->pdev,
 					virt_to_page(skb->data),
-					((unsigned long) skb->data &
-					 ~PAGE_MASK),
+					offset_in_page(skb->data),
 					RX_BUF_ALLOC_SIZE(gp),
 					PCI_DMA_FROMDEVICE);
 		rxd->buffer = cpu_to_le64(dma_addr);

drivers/scsi/3w-xxxx.c

@@ -2112,7 +2112,7 @@ static u32 tw_map_scsi_single_data(struct pci_dev *pdev, Scsi_Cmnd *cmd)
 	if (cmd->request_bufflen == 0)
 		return 0;
 
-	mapping = pci_map_page(pdev, virt_to_page(cmd->request_buffer), ((unsigned long)cmd->request_buffer & ~PAGE_MASK), cmd->request_bufflen, dma_dir);
+	mapping = pci_map_page(pdev, virt_to_page(cmd->request_buffer), offset_in_page(cmd->request_buffer), cmd->request_bufflen, dma_dir);
 
 	if (mapping == 0) {
 		printk(KERN_WARNING "3w-xxxx: tw_map_scsi_single_data(): pci_map_page() failed.\n");

drivers/scsi/arm/scsi.h

@@ -23,7 +23,7 @@ static inline int copy_SCp_to_sg(struct scatterlist *sg, Scsi_Pointer *SCp, int
 	BUG_ON(bufs + 1 > max);
 
 	sg->page   = virt_to_page(SCp->ptr);
-	sg->offset = ((unsigned int)SCp->ptr) & ~PAGE_MASK;
+	sg->offset = offset_in_page(SCp->ptr);
 	sg->length = SCp->this_residual;
 
 	if (bufs)

drivers/scsi/ide-scsi.c

@@ -761,8 +761,8 @@ static inline struct bio *idescsi_dma_bio(ide_drive_t *drive, idescsi_pc_t *pc)
 		printk ("ide-scsi: %s: building DMA table for a single buffer (%dkB)\n", drive->name, pc->request_transfer >> 10);
 #endif /* IDESCSI_DEBUG_LOG */
 		bh->bi_io_vec[0].bv_page = virt_to_page(pc->scsi_cmd->request_buffer);
+		bh->bi_io_vec[0].bv_offset = offset_in_page(pc->scsi_cmd->request_buffer);
 		bh->bi_io_vec[0].bv_len = pc->request_transfer;
-		bh->bi_io_vec[0].bv_offset = (unsigned long) pc->scsi_cmd->request_buffer & ~PAGE_MASK;
 		bh->bi_size = pc->request_transfer;
 	}
 	return first_bh;

drivers/scsi/megaraid.c

@@ -2275,8 +2275,7 @@ mega_build_sglist(adapter_t *adapter, scb_t *scb, u32 *buf, u32 *len)
 	if( !cmd->use_sg ) {
 
 		page = virt_to_page(cmd->request_buffer);
-
-		offset = ((unsigned long)cmd->request_buffer & ~PAGE_MASK);
+		offset = offset_in_page(cmd->request_buffer);
 
 		scb->dma_h_bulkdata = pci_map_page(adapter->dev,
 						  page, offset,

drivers/scsi/qlogicfc.c

@@ -1282,8 +1282,7 @@ int isp2x00_queuecommand(Scsi_Cmnd * Cmnd, void (*done) (Scsi_Cmnd *))
 		}
 	} else if (Cmnd->request_bufflen && Cmnd->sc_data_direction != PCI_DMA_NONE) {
 		struct page *page = virt_to_page(Cmnd->request_buffer);
-		unsigned long offset = ((unsigned long)Cmnd->request_buffer &
-					~PAGE_MASK);
+		unsigned long offset = offset_in_page(Cmnd->request_buffer);
 		dma_addr_t busaddr = pci_map_page(hostdata->pci_dev,
 						  page, offset,
 						  Cmnd->request_bufflen,
@@ -1926,8 +1925,7 @@ static int isp2x00_reset_hardware(struct Scsi_Host *host)
 	 */
 	busaddr = pci_map_page(hostdata->pci_dev,
 			       virt_to_page(&hostdata->control_block),
-			       ((unsigned long) &hostdata->control_block &
-				~PAGE_MASK),
+			       offset_in_page(&hostdata->control_block),
 			       sizeof(hostdata->control_block),
 			       PCI_DMA_BIDIRECTIONAL);
 

drivers/scsi/sg.c

@@ -1814,7 +1814,7 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
 					break;
 			}
 			sclp->page = virt_to_page(p);
-			sclp->offset = (unsigned long) p & ~PAGE_MASK;
+			sclp->offset = offset_in_page(p);
 			sclp->length = ret_sz;
 
 			SCSI_LOG_TIMEOUT(5, printk("sg_build_build: k=%d, a=0x%p, len=%d\n",

drivers/scsi/sym53c8xx.c

@@ -1162,8 +1162,7 @@ static dma_addr_t __map_scsi_single_data(pcidev_t pdev, Scsi_Cmnd *cmd)
 
 	mapping = pci_map_page(pdev,
 			       virt_to_page(cmd->request_buffer),
-			       ((unsigned long)cmd->request_buffer &
-				~PAGE_MASK),
+			       offset_in_page(cmd->request_buffer),
 			       cmd->request_bufflen, dma_dir);
 	__data_mapped(cmd) = 1;
 	__data_mapping(cmd) = mapping;

drivers/usb/misc/usbtest.c

@@ -271,7 +271,7 @@ alloc_sglist (int nents, int max, int vary)
 
 		/* kmalloc pages are always physically contiguous! */
 		sg [i].page = virt_to_page (buf);
-		sg [i].offset = ((unsigned) buf) & ~PAGE_MASK;
+		sg [i].offset = offset_in_page (buf);
 		sg [i].length = size;
 
 		if (vary) {

drivers/usb/storage/sddr09.c

@@ -1127,7 +1127,7 @@ sddr09_read_map(struct us_data *us) {
 		char *vaddr = kmalloc(alloc_req, GFP_NOIO);
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,3)
 		sg[i].page = virt_to_page(vaddr);
-		sg[i].offset = ((unsigned long)vaddr & ~PAGE_MASK);
+		sg[i].offset = offset_in_page(vaddr);
 #else
 		sg[i].address = vaddr;
 #endif

fs/jbd/journal.c

@@ -278,9 +278,6 @@ static void journal_kill_thread(journal_t *journal)
  * Bit 1 set == buffer copy-out performed (kfree the data after IO)
  */
 
-static inline unsigned long virt_to_offset(void *p) 
-{return ((unsigned long) p) & ~PAGE_MASK;}
-					       
 int journal_write_metadata_buffer(transaction_t *transaction,
 				  struct journal_head  *jh_in,
 				  struct journal_head **jh_out,
@@ -318,10 +315,10 @@ int journal_write_metadata_buffer(transaction_t *transaction,
 	if (jh_in->b_frozen_data) {
 		done_copy_out = 1;
 		new_page = virt_to_page(jh_in->b_frozen_data);
-		new_offset = virt_to_offset(jh_in->b_frozen_data);
+		new_offset = offset_in_page(jh_in->b_frozen_data);
 	} else {
 		new_page = jh2bh(jh_in)->b_page;
-		new_offset = virt_to_offset(jh2bh(jh_in)->b_data);
+		new_offset = offset_in_page(jh2bh(jh_in)->b_data);
 	}
 
 	mapped_data = kmap_atomic(new_page, KM_USER0);
@@ -358,7 +355,7 @@ int journal_write_metadata_buffer(transaction_t *transaction,
 		   address kmapped so that we can clear the escaped
 		   magic number below. */
 		new_page = virt_to_page(tmp);
-		new_offset = virt_to_offset(tmp);
+		new_offset = offset_in_page(tmp);
 		done_copy_out = 1;
 	}
 

include/linux/mm.h

@@ -400,6 +400,8 @@ static inline int page_mapped(struct page *page)
 #define VM_FAULT_MINOR	1
 #define VM_FAULT_MAJOR	2
 
+#define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
+
 extern void show_free_areas(void);
 
 struct page *shmem_nopage(struct vm_area_struct * vma,

net/ipv6/addrconf.c

@@ -1110,10 +1110,10 @@ static int __ipv6_regen_rndid(struct inet6_dev *idev)
 	struct scatterlist sg[2];
 
 	sg[0].page = virt_to_page(idev->entropy);
-	sg[0].offset = ((long) idev->entropy & ~PAGE_MASK);
+	sg[0].offset = offset_in_page(idev->entropy);
 	sg[0].length = 8;
 	sg[1].page = virt_to_page(eui64);
-	sg[1].offset = ((long) eui64 & ~PAGE_MASK);
+	sg[1].offset = offset_in_page(eui64);
 	sg[1].length = 8;
 
 	dev = idev->dev;

net/sunrpc/auth_gss/gss_krb5_crypto.c

@@ -75,7 +75,7 @@ krb5_encrypt(
 
 	memcpy(out, in, length);
 	sg[0].page = virt_to_page(out);
-	sg[0].offset = ((long)out & ~PAGE_MASK);
+	sg[0].offset = offset_in_page(out);
 	sg[0].length = length;
 
 	ret = crypto_cipher_encrypt(tfm, sg, sg, length);
@@ -114,7 +114,7 @@ krb5_decrypt(
 
 	memcpy(out, in, length);
 	sg[0].page = virt_to_page(out);
-	sg[0].offset = ((long)out  & ~PAGE_MASK);
+	sg[0].offset = offset_in_page(out);
 	sg[0].length = length;
 
 	ret = crypto_cipher_decrypt(tfm, sg, sg, length);
@@ -151,7 +151,7 @@ krb5_make_checksum(s32 cksumtype, struct xdr_netobj *input,
 		goto out_free_tfm;
 	}
 	sg[0].page = virt_to_page(input->data);
-	sg[0].offset = ((long)input->data & ~PAGE_MASK);
+	sg[0].offset = offset_in_page(input->data);
 	sg[0].length = input->len;
 
 	crypto_digest_init(tfm);