net: use skb_for_each_frag() helper where possible

use the new helper macro skb_for_each_frag() which allows to iterate
through all the SKB fragments.

The patch was created with Coccinelle, this was the semantic patch:

@@
struct sk_buff *skb;
identifier i;
statement S;
iterator name skb_for_each_frag;
@@
-for (i = 0; i < skb_shinfo(skb)->nr_frags; \(++i\|i++\))
+skb_for_each_frag(skb, i)
 S
@@
struct skb_shared_info *sinfo;
struct sk_buff *skb;
identifier i;
statement S;
iterator name skb_for_each_frag;
@@
 sinfo = skb_shinfo(skb);
 ...
-for (i = 0; i < sinfo->nr_frags; \(++i\|i++\))
+skb_for_each_frag(skb, i)
 S
@@
struct sk_buff *skb;
identifier i, num_frags;
statement S;
iterator name skb_for_each_frag;
@@
 num_frags = skb_shinfo(skb)->nr_frags;
 ...
-for (i = 0; i < num_frags; \(++i\|i++\))
+skb_for_each_frag(skb, i)
 S

Tested with an allmodconfig build.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>

arch/um/drivers/vector_kern.c

@@ -315,7 +315,7 @@ static int prep_msg(struct vector_private *vp,
 	} else
 		iov[iov_index].iov_len = skb->len;
 	iov_index++;
-	for (frag = 0; frag < nr_frags; frag++) {
+	skb_for_each_frag(skb, frag) {
 		skb_frag = &skb_shinfo(skb)->frags[frag];
 		iov[iov_index].iov_base = skb_frag_address_safe(skb_frag);
 		iov[iov_index].iov_len = skb_frag_size(skb_frag);
@@ -657,7 +657,7 @@ static struct sk_buff *prep_skb(
 	iov_index++;
 
 	nr_frags = skb_shinfo(result)->nr_frags;
-	for (frag = 0; frag < nr_frags; frag++) {
+	skb_for_each_frag(result, frag) {
 		skb_frag = &skb_shinfo(result)->frags[frag];
 		iov[iov_index].iov_base = skb_frag_address_safe(skb_frag);
 		if (iov[iov_index].iov_base != NULL)

drivers/atm/he.c

@@ -2556,7 +2556,7 @@ he_send(struct atm_vcc *vcc, struct sk_buff *skb)
 	tpd->iovec[slot].len = skb_headlen(skb);
 	++slot;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		if (slot == TPD_MAXIOV) {	/* queue tpd; start new tpd */

drivers/hsi/clients/ssi_protocol.c

@@ -177,7 +177,7 @@ static void ssip_skb_to_msg(struct sk_buff *skb, struct hsi_msg *msg)
 
 	sg = msg->sgt.sgl;
 	sg_set_buf(sg, skb->data, skb_headlen(skb));
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		sg = sg_next(sg);
 		BUG_ON(!sg);
 		frag = &skb_shinfo(skb)->frags[i];

drivers/infiniband/hw/hfi1/ipoib_tx.c

@@ -240,7 +240,7 @@ static int hfi1_ipoib_build_ulp_payload(struct ipoib_txreq *tx,
 			return ret;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		ret = sdma_txadd_page(dd,

drivers/infiniband/hw/hfi1/vnic_sdma.c

@@ -101,7 +101,7 @@ static noinline int build_vnic_ulp_payload(struct sdma_engine *sde,
 	if (unlikely(ret))
 		goto bail_txadd;
 
-	for (i = 0; i < skb_shinfo(tx->skb)->nr_frags; i++) {
+	skb_for_each_frag(tx->skb, i) {
 		skb_frag_t *frag = &skb_shinfo(tx->skb)->frags[i];
 
 		/* combine physically continuous fragments later? */

drivers/infiniband/ulp/ipoib/ipoib_cm.c

@@ -537,7 +537,7 @@ static void skb_put_frags(struct sk_buff *skb, unsigned int hdr_space,
 	length -= size;
 
 	num_frags = skb_shinfo(skb)->nr_frags;
-	for (i = 0; i < num_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		if (length == 0) {

drivers/infiniband/ulp/ipoib/ipoib_ib.c

@@ -289,7 +289,7 @@ int ipoib_dma_map_tx(struct ib_device *ca, struct ipoib_tx_buf *tx_req)
 	} else
 		off = 0;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		mapping[i + off] = ib_dma_map_page(ca,
 						 skb_frag_page(frag),
@@ -329,7 +329,7 @@ void ipoib_dma_unmap_tx(struct ipoib_dev_priv *priv,
 	} else
 		off = 0;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		ib_dma_unmap_page(priv->ca, mapping[i + off],

drivers/net/ethernet/3com/3c59x.c

@@ -2168,7 +2168,7 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		vp->tx_ring[entry].frag[0].addr = cpu_to_le32(dma_addr);
 		vp->tx_ring[entry].frag[0].length = cpu_to_le32(skb_headlen(skb));
 
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 			dma_addr = skb_frag_dma_map(vp->gendev, frag,

drivers/net/ethernet/3com/typhoon.c

@@ -808,7 +808,7 @@ typhoon_start_tx(struct sk_buff *skb, struct net_device *dev)
 		txd->frag.addrHi = 0;
 		first_txd->numDesc++;
 
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 			void *frag_addr;
 

drivers/net/ethernet/adaptec/starfire.c

@@ -1368,7 +1368,7 @@ static irqreturn_t intr_handler(int irq, void *dev_instance)
 				entry = (entry + np->tx_info[entry].used_slots) % TX_RING_SIZE;
 				{
 					int i;
-					for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+					skb_for_each_frag(skb, i) {
 						dma_unmap_single(&np->pci_dev->dev,
 								 np->tx_info[entry].mapping,
 								 skb_frag_size(&skb_shinfo(skb)->frags[i]),

drivers/net/ethernet/aeroflex/greth.c

@@ -106,7 +106,7 @@ static void greth_print_tx_packet(struct sk_buff *skb)
 	print_hex_dump(KERN_DEBUG, "TX: ", DUMP_PREFIX_OFFSET, 16, 1,
 			skb->data, length, true);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 
 		print_hex_dump(KERN_DEBUG, "TX: ", DUMP_PREFIX_OFFSET, 16, 1,
 			       skb_frag_address(&skb_shinfo(skb)->frags[i]),
@@ -514,7 +514,7 @@ greth_start_xmit_gbit(struct sk_buff *skb, struct net_device *dev)
 	curr_tx = NEXT_TX(greth->tx_next);
 
 	/* Frags */
-	for (i = 0; i < nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		greth->tx_skbuff[curr_tx] = NULL;
 		bdp = greth->tx_bd_base + curr_tx;
@@ -710,7 +710,7 @@ static void greth_clean_tx_gbit(struct net_device *dev)
 				 skb_headlen(skb),
 				 DMA_TO_DEVICE);
 
-		for (i = 0; i < nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 			bdp = greth->tx_bd_base + tx_last;
 

drivers/net/ethernet/alteon/acenic.c

@@ -2453,7 +2453,7 @@ static netdev_tx_t ace_start_xmit(struct sk_buff *skb,
 
 		idx = (idx + 1) % ACE_TX_RING_ENTRIES(ap);
 
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 			struct tx_ring_info *info;
 

drivers/net/ethernet/amazon/ena/ena_netdev.c

@@ -2965,7 +2965,7 @@ static int ena_tx_map_skb(struct ena_ring *tx_ring,
 
 	last_frag = skb_shinfo(skb)->nr_frags;
 
-	for (i = 0; i < last_frag; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		frag_len = skb_frag_size(frag);

drivers/net/ethernet/amd/xgbe/xgbe-desc.c

@@ -600,7 +600,7 @@ static int xgbe_map_tx_skb(struct xgbe_channel *channel, struct sk_buff *skb)
 		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		netif_dbg(pdata, tx_queued, pdata->netdev,
 			  "mapping frag %u\n", i);
 

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

@@ -1806,7 +1806,7 @@ static void xgbe_packet_info(struct xgbe_prv_data *pdata,
 		len -= min_t(unsigned int, len, XGBE_TX_MAX_BUF_SIZE);
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 		for (len = skb_frag_size(frag); len; ) {
 			packet->rdesc_count++;

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

@@ -244,7 +244,7 @@ static int xgene_enet_tx_completion(struct xgene_enet_desc_ring *cp_ring,
 			 skb_headlen(skb),
 			 DMA_TO_DEVICE);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 		dma_unmap_page(dev, frag_dma_addr[i], skb_frag_size(frag),
 			       DMA_TO_DEVICE);

drivers/net/ethernet/atheros/alx/main.c

@@ -1465,7 +1465,7 @@ static int alx_map_tx_skb(struct alx_tx_queue *txq, struct sk_buff *skb)
 	tpd->adrl.addr = cpu_to_le64(dma);
 	tpd->len = cpu_to_le16(maplen);
 
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[f];
 
 		if (++txq->write_idx == txq->count)

drivers/net/ethernet/atheros/atl1c/atl1c_main.c

@@ -2151,7 +2151,7 @@ static int atl1c_tx_map(struct atl1c_adapter *adapter,
 		use_tpd->buffer_len  = cpu_to_le16(buffer_info->length);
 	}
 
-	for (f = 0; f < nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[f];
 
 		use_tpd = atl1c_get_tpd(adapter, type);

drivers/net/ethernet/atheros/atl1e/atl1e_main.c

@@ -1601,7 +1601,7 @@ static u16 atl1e_cal_tdp_req(const struct sk_buff *skb)
 	u16 fg_size = 0;
 	u16 proto_hdr_len = 0;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		fg_size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
 		tpd_req += ((fg_size + MAX_TX_BUF_LEN - 1) >> MAX_TX_BUF_SHIFT);
 	}
@@ -1777,7 +1777,7 @@ static int atl1e_tx_map(struct atl1e_adapter *adapter,
 			TPD_BUFLEN_MASK) << TPD_BUFLEN_SHIFT);
 	}
 
-	for (f = 0; f < nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[f];
 		u16 i;
 		u16 seg_num;

drivers/net/ethernet/atheros/atlx/atl1.c

@@ -2255,7 +2255,7 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb,
 			next_to_use = 0;
 	}
 
-	for (f = 0; f < nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[f];
 		u16 i, nseg;
 
@@ -2358,7 +2358,7 @@ static netdev_tx_t atl1_xmit_frame(struct sk_buff *skb,
 	}
 
 	nr_frags = skb_shinfo(skb)->nr_frags;
-	for (f = 0; f < nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		unsigned int f_size = skb_frag_size(&skb_shinfo(skb)->frags[f]);
 		count += (f_size + ATL1_MAX_TX_BUF_LEN - 1) /
 			 ATL1_MAX_TX_BUF_LEN;

drivers/net/ethernet/broadcom/bgmac.c

@@ -171,7 +171,7 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
 	bgmac_dma_tx_add_buf(bgmac, ring, index, skb_headlen(skb), flags);
 	flags = 0;
 
-	for (i = 0; i < nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		int len = skb_frag_size(frag);
 

drivers/net/ethernet/broadcom/bnx2.c

@@ -6681,7 +6681,7 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	tx_buf->nr_frags = last_frag;
 	tx_buf->is_gso = skb_is_gso(skb);
 
-	for (i = 0; i < last_frag; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		prod = BNX2_NEXT_TX_BD(prod);

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

@@ -4071,7 +4071,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	tx_data_bd = (struct eth_tx_bd *)tx_start_bd;
 
 	/* Handle fragmented skb */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		mapping = skb_frag_dma_map(&bp->pdev->dev, frag, 0,

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -433,7 +433,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 		skb_copy_from_linear_data(skb, pdata, len);
 		pdata += len;
-		for (j = 0; j < last_frag; j++) {
+		skb_for_each_frag(skb, j) {
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[j];
 			void *fptr;
 
@@ -537,7 +537,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	txbd1->tx_bd_cfa_meta = cpu_to_le32(vlan_tag_flags);
 	txbd1->tx_bd_cfa_action =
 			cpu_to_le32(cfa_action << TX_BD_CFA_ACTION_SHIFT);
-	for (i = 0; i < last_frag; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		prod = NEXT_TX(prod);
@@ -606,7 +606,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	prod = NEXT_TX(prod);
 
 	/* unmap remaining mapped pages */
-	for (i = 0; i < last_frag; i++) {
+	skb_for_each_frag(skb, i) {
 		prod = NEXT_TX(prod);
 		tx_buf = &txr->tx_buf_ring[prod];
 		dma_unmap_page(&pdev->dev, dma_unmap_addr(tx_buf, mapping),

drivers/net/ethernet/broadcom/tg3.c

@@ -6579,7 +6579,7 @@ static void tg3_tx(struct tg3_napi *tnapi)
 
 		sw_idx = NEXT_TX(sw_idx);
 
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			ri = &tnapi->tx_buffers[sw_idx];
 			if (unlikely(ri->skb != NULL || sw_idx == hw_idx))
 				tx_bug = 1;

drivers/net/ethernet/cadence/macb_main.c

@@ -2058,7 +2058,7 @@ static netdev_features_t macb_features_check(struct sk_buff *skb,
 	nr_frags = skb_shinfo(skb)->nr_frags;
 	/* No need to check last fragment */
 	nr_frags--;
-	for (f = 0; f < nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[f];
 
 		if (!IS_ALIGNED(skb_frag_size(frag), MACB_TX_LEN_ALIGN))
@@ -2200,7 +2200,7 @@ static netdev_tx_t macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	else
 		desc_cnt = DIV_ROUND_UP(skb_headlen(skb), bp->max_tx_length);
 	nr_frags = skb_shinfo(skb)->nr_frags;
-	for (f = 0; f < nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		frag_size = skb_frag_size(&skb_shinfo(skb)->frags[f]);
 		desc_cnt += DIV_ROUND_UP(frag_size, bp->max_tx_length);
 	}

drivers/net/ethernet/cavium/thunder/nicvf_queues.c

@@ -1587,7 +1587,7 @@ int nicvf_sq_append_skb(struct nicvf *nic, struct snd_queue *sq,
 	if (!skb_is_nonlinear(skb))
 		goto doorbell;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		qentry = nicvf_get_nxt_sqentry(sq, qentry);

drivers/net/ethernet/chelsio/cxgb3/sge.c

@@ -1021,7 +1021,7 @@ static inline unsigned int write_sgl(const struct sk_buff *skb,
 	}
 
 	nfrags = skb_shinfo(skb)->nr_frags;
-	for (i = 0; i < nfrags; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		sgp->len[j] = cpu_to_be32(skb_frag_size(frag));
@@ -1595,7 +1595,7 @@ static void deferred_unmap_destructor(struct sk_buff *skb)
 				 skb_transport_header(skb), PCI_DMA_TODEVICE);
 
 	si = skb_shinfo(skb);
-	for (i = 0; i < si->nr_frags; i++)
+	skb_for_each_frag(skb, i)
 		pci_unmap_page(dui->pdev, *p++, skb_frag_size(&si->frags[i]),
 			       PCI_DMA_TODEVICE);
 }

drivers/net/ethernet/emulex/benet/be_main.c

@@ -1012,7 +1012,7 @@ static u32 be_xmit_enqueue(struct be_adapter *adapter, struct be_tx_obj *txo,
 		copied += len;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		len = skb_frag_size(frag);
 

drivers/net/ethernet/faraday/ftgmac100.c

@@ -773,7 +773,7 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
 	pointer = ftgmac100_next_tx_pointer(priv, pointer);
 
 	/* Add the fragments */
-	for (i = 0; i < nfrags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		len = skb_frag_size(frag);

drivers/net/ethernet/freescale/dpaa/dpaa_eth.c

@@ -2119,7 +2119,7 @@ static int dpaa_a050385_wa_skb(struct net_device *net_dev, struct sk_buff **s)
 	if (!IS_ALIGNED(skb_headlen(skb), DPAA_A050385_ALIGN))
 		goto workaround;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		/* all fragments need to have aligned start addresses */

drivers/net/ethernet/freescale/gianfar.c

@@ -1102,8 +1102,7 @@ static void free_skb_tx_queue(struct gfar_priv_tx_q *tx_queue)
 		dma_unmap_single(priv->dev, be32_to_cpu(txbdp->bufPtr),
 				 be16_to_cpu(txbdp->length), DMA_TO_DEVICE);
 		txbdp->lstatus = 0;
-		for (j = 0; j < skb_shinfo(tx_queue->tx_skbuff[i])->nr_frags;
-		     j++) {
+		skb_for_each_frag(tx_queue->tx_skbuff[i], j) {
 			txbdp++;
 			dma_unmap_page(priv->dev, be32_to_cpu(txbdp->bufPtr),
 				       be16_to_cpu(txbdp->length),
@@ -2250,7 +2249,7 @@ static void gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue)
 		gfar_clear_txbd_status(bdp);
 		bdp = next_txbd(bdp, base, tx_ring_size);
 
-		for (i = 0; i < frags; i++) {
+		skb_for_each_frag(skb, i) {
 			dma_unmap_page(priv->dev, be32_to_cpu(bdp->bufPtr),
 				       be16_to_cpu(bdp->length),
 				       DMA_TO_DEVICE);