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* [PATCH net-next 0/3] introduce skb_for_each_frag()
@ 2021-04-09 18:06 Matteo Croce
  2021-04-09 18:06 ` [PATCH net-next 1/3] skbuff: add helper to walk over the fraglist Matteo Croce
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Matteo Croce @ 2021-04-09 18:06 UTC (permalink / raw)
  To: netdev; +Cc: linux-kernel, David S. Miller, Jakub Kicinski, Julia Lawall

From: Matteo Croce <mcroce@microsoft.com>

Introduce skb_for_each_frag, an helper macro to iterate over the SKB frags.

First patch introduces the helper, the second one is generated with
coccinelle and uses the macro where possible.
Last one is a chunk which have to be applied by hand.

The second patch raises some checkpatch.pl warnings because part of
net/tls/tls_sw.c is indented with spaces.

Build tested with an allmodconfig and a test run.

Matteo Croce (3):
  skbuff: add helper to walk over the fraglist
  net: use skb_for_each_frag() helper where possible
  net: use skb_for_each_frag() in illegal_highdma()

 arch/um/drivers/vector_kern.c                 |  4 +--
 drivers/atm/he.c                              |  2 +-
 drivers/hsi/clients/ssi_protocol.c            |  2 +-
 drivers/infiniband/hw/hfi1/ipoib_tx.c         |  2 +-
 drivers/infiniband/hw/hfi1/vnic_sdma.c        |  2 +-
 drivers/infiniband/ulp/ipoib/ipoib_cm.c       |  2 +-
 drivers/infiniband/ulp/ipoib/ipoib_ib.c       |  4 +--
 drivers/net/ethernet/3com/3c59x.c             |  2 +-
 drivers/net/ethernet/3com/typhoon.c           |  2 +-
 drivers/net/ethernet/adaptec/starfire.c       |  2 +-
 drivers/net/ethernet/aeroflex/greth.c         |  6 ++--
 drivers/net/ethernet/alteon/acenic.c          |  2 +-
 drivers/net/ethernet/amazon/ena/ena_netdev.c  |  2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-desc.c     |  2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-drv.c      |  2 +-
 .../net/ethernet/apm/xgene/xgene_enet_main.c  |  2 +-
 drivers/net/ethernet/atheros/alx/main.c       |  2 +-
 .../net/ethernet/atheros/atl1c/atl1c_main.c   |  2 +-
 .../net/ethernet/atheros/atl1e/atl1e_main.c   |  4 +--
 drivers/net/ethernet/atheros/atlx/atl1.c      |  4 +--
 drivers/net/ethernet/broadcom/bgmac.c         |  2 +-
 drivers/net/ethernet/broadcom/bnx2.c          |  2 +-
 .../net/ethernet/broadcom/bnx2x/bnx2x_cmn.c   |  2 +-
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  6 ++--
 drivers/net/ethernet/broadcom/tg3.c           |  2 +-
 drivers/net/ethernet/cadence/macb_main.c      |  4 +--
 .../ethernet/cavium/thunder/nicvf_queues.c    |  2 +-
 drivers/net/ethernet/chelsio/cxgb3/sge.c      |  4 +--
 drivers/net/ethernet/emulex/benet/be_main.c   |  2 +-
 drivers/net/ethernet/faraday/ftgmac100.c      |  2 +-
 .../net/ethernet/freescale/dpaa/dpaa_eth.c    |  2 +-
 drivers/net/ethernet/freescale/gianfar.c      |  5 ++--
 drivers/net/ethernet/hisilicon/hix5hd2_gmac.c |  4 +--
 drivers/net/ethernet/hisilicon/hns/hns_enet.c |  2 +-
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |  4 +--
 drivers/net/ethernet/huawei/hinic/hinic_rx.c  |  2 +-
 drivers/net/ethernet/huawei/hinic/hinic_tx.c  |  4 +--
 drivers/net/ethernet/ibm/ibmveth.c            |  2 +-
 drivers/net/ethernet/ibm/ibmvnic.c            |  2 +-
 drivers/net/ethernet/intel/e1000/e1000_main.c |  2 +-
 drivers/net/ethernet/intel/e1000e/netdev.c    |  2 +-
 drivers/net/ethernet/intel/fm10k/fm10k_main.c |  2 +-
 drivers/net/ethernet/intel/igb/igb_main.c     |  2 +-
 drivers/net/ethernet/intel/igbvf/netdev.c     |  2 +-
 drivers/net/ethernet/intel/igc/igc_main.c     |  2 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  2 +-
 .../net/ethernet/intel/ixgbevf/ixgbevf_main.c |  2 +-
 drivers/net/ethernet/marvell/mv643xx_eth.c    |  2 +-
 .../net/ethernet/marvell/mvpp2/mvpp2_main.c   |  2 +-
 drivers/net/ethernet/marvell/skge.c           |  2 +-
 drivers/net/ethernet/marvell/sky2.c           | 10 +++----
 drivers/net/ethernet/mediatek/mtk_eth_soc.c   |  4 +--
 .../net/ethernet/mellanox/mlx5/core/en_tx.c   |  2 +-
 drivers/net/ethernet/mellanox/mlxsw/pci.c     |  2 +-
 drivers/net/ethernet/microchip/lan743x_main.c |  2 +-
 drivers/net/ethernet/neterion/s2io.c          |  2 +-
 .../net/ethernet/neterion/vxge/vxge-main.c    |  6 ++--
 drivers/net/ethernet/ni/nixge.c               |  2 +-
 drivers/net/ethernet/pasemi/pasemi_mac.c      |  2 +-
 .../ethernet/qlogic/netxen/netxen_nic_main.c  |  2 +-
 drivers/net/ethernet/qlogic/qed/qed_ll2.c     |  2 +-
 .../net/ethernet/qlogic/qlcnic/qlcnic_io.c    |  2 +-
 drivers/net/ethernet/realtek/8139cp.c         |  2 +-
 drivers/net/ethernet/rocker/rocker_main.c     |  2 +-
 drivers/net/ethernet/sfc/tx.c                 |  2 +-
 drivers/net/ethernet/sun/cassini.c            |  2 +-
 drivers/net/ethernet/sun/niu.c                |  4 +--
 drivers/net/ethernet/sun/sungem.c             |  2 +-
 drivers/net/ethernet/sun/sunhme.c             |  2 +-
 drivers/net/ethernet/sun/sunvnet_common.c     |  4 +--
 .../net/ethernet/synopsys/dwc-xlgmac-desc.c   |  2 +-
 .../net/ethernet/synopsys/dwc-xlgmac-net.c    |  2 +-
 drivers/net/ethernet/ti/am65-cpsw-nuss.c      |  2 +-
 drivers/net/ethernet/ti/netcp_core.c          |  2 +-
 drivers/net/ethernet/via/via-velocity.c       |  2 +-
 drivers/net/ethernet/xilinx/ll_temac_main.c   |  2 +-
 .../net/ethernet/xilinx/xilinx_axienet_main.c |  2 +-
 drivers/net/usb/usbnet.c                      |  2 +-
 drivers/net/vmxnet3/vmxnet3_drv.c             |  4 +--
 drivers/net/wireless/intel/iwlwifi/pcie/tx.c  |  2 +-
 drivers/net/wireless/intel/iwlwifi/queue/tx.c |  2 +-
 drivers/net/xen-netback/netback.c             |  2 +-
 drivers/net/xen-netfront.c                    |  2 +-
 drivers/s390/net/qeth_core_main.c             |  4 +--
 drivers/scsi/fcoe/fcoe_transport.c            |  2 +-
 drivers/staging/octeon/ethernet-tx.c          |  2 +-
 include/linux/skbuff.h                        |  4 +++
 net/appletalk/ddp.c                           |  2 +-
 net/core/datagram.c                           |  4 +--
 net/core/dev.c                                |  2 +-
 net/core/skbuff.c                             | 30 +++++++++----------
 net/ipv4/inet_fragment.c                      |  2 +-
 net/ipv4/tcp_output.c                         |  2 +-
 net/iucv/af_iucv.c                            |  4 +--
 net/kcm/kcmsock.c                             |  3 +-
 net/tls/tls_sw.c                              |  2 +-
 96 files changed, 140 insertions(+), 138 deletions(-)

-- 
2.30.2


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH net-next 1/3] skbuff: add helper to walk over the fraglist
  2021-04-09 18:06 [PATCH net-next 0/3] introduce skb_for_each_frag() Matteo Croce
@ 2021-04-09 18:06 ` Matteo Croce
  2021-04-09 18:06 ` [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible Matteo Croce
  2021-04-09 18:06 ` [PATCH net-next 3/3] net: use skb_for_each_frag() in illegal_highdma() Matteo Croce
  2 siblings, 0 replies; 10+ messages in thread
From: Matteo Croce @ 2021-04-09 18:06 UTC (permalink / raw)
  To: netdev; +Cc: linux-kernel, David S. Miller, Jakub Kicinski, Julia Lawall

From: Matteo Croce <mcroce@microsoft.com>

Add an skb_for_each_frag() macro to iterate on SKB fragments.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
 include/linux/skbuff.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index dbf820a50a39..a8d4ccacdda5 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1528,6 +1528,10 @@ static inline void skb_mark_not_on_list(struct sk_buff *skb)
 	for ((skb) = (first), (next_skb) = (skb) ? (skb)->next : NULL; (skb);  \
 	     (skb) = (next_skb), (next_skb) = (skb) ? (skb)->next : NULL)
 
+/* Iterate through skb fragments. */
+#define skb_for_each_frag(skb, __i) \
+	for (__i = 0; __i < skb_shinfo(skb)->nr_frags; __i++)
+
 static inline void skb_list_del_init(struct sk_buff *skb)
 {
 	__list_del_entry(&skb->list);
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 18:06 [PATCH net-next 0/3] introduce skb_for_each_frag() Matteo Croce
  2021-04-09 18:06 ` [PATCH net-next 1/3] skbuff: add helper to walk over the fraglist Matteo Croce
@ 2021-04-09 18:06 ` Matteo Croce
  2021-04-09 18:54   ` Jakub Kicinski
                     ` (2 more replies)
  2021-04-09 18:06 ` [PATCH net-next 3/3] net: use skb_for_each_frag() in illegal_highdma() Matteo Croce
  2 siblings, 3 replies; 10+ messages in thread
From: Matteo Croce @ 2021-04-09 18:06 UTC (permalink / raw)
  To: netdev; +Cc: linux-kernel, David S. Miller, Jakub Kicinski, Julia Lawall

From: Matteo Croce <mcroce@microsoft.com>

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                 |  4 +--
 drivers/atm/he.c                              |  2 +-
 drivers/hsi/clients/ssi_protocol.c            |  2 +-
 drivers/infiniband/hw/hfi1/ipoib_tx.c         |  2 +-
 drivers/infiniband/hw/hfi1/vnic_sdma.c        |  2 +-
 drivers/infiniband/ulp/ipoib/ipoib_cm.c       |  2 +-
 drivers/infiniband/ulp/ipoib/ipoib_ib.c       |  4 +--
 drivers/net/ethernet/3com/3c59x.c             |  2 +-
 drivers/net/ethernet/3com/typhoon.c           |  2 +-
 drivers/net/ethernet/adaptec/starfire.c       |  2 +-
 drivers/net/ethernet/aeroflex/greth.c         |  6 ++--
 drivers/net/ethernet/alteon/acenic.c          |  2 +-
 drivers/net/ethernet/amazon/ena/ena_netdev.c  |  2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-desc.c     |  2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-drv.c      |  2 +-
 .../net/ethernet/apm/xgene/xgene_enet_main.c  |  2 +-
 drivers/net/ethernet/atheros/alx/main.c       |  2 +-
 .../net/ethernet/atheros/atl1c/atl1c_main.c   |  2 +-
 .../net/ethernet/atheros/atl1e/atl1e_main.c   |  4 +--
 drivers/net/ethernet/atheros/atlx/atl1.c      |  4 +--
 drivers/net/ethernet/broadcom/bgmac.c         |  2 +-
 drivers/net/ethernet/broadcom/bnx2.c          |  2 +-
 .../net/ethernet/broadcom/bnx2x/bnx2x_cmn.c   |  2 +-
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  6 ++--
 drivers/net/ethernet/broadcom/tg3.c           |  2 +-
 drivers/net/ethernet/cadence/macb_main.c      |  4 +--
 .../ethernet/cavium/thunder/nicvf_queues.c    |  2 +-
 drivers/net/ethernet/chelsio/cxgb3/sge.c      |  4 +--
 drivers/net/ethernet/emulex/benet/be_main.c   |  2 +-
 drivers/net/ethernet/faraday/ftgmac100.c      |  2 +-
 .../net/ethernet/freescale/dpaa/dpaa_eth.c    |  2 +-
 drivers/net/ethernet/freescale/gianfar.c      |  5 ++--
 drivers/net/ethernet/hisilicon/hix5hd2_gmac.c |  4 +--
 drivers/net/ethernet/hisilicon/hns/hns_enet.c |  2 +-
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |  4 +--
 drivers/net/ethernet/huawei/hinic/hinic_rx.c  |  2 +-
 drivers/net/ethernet/huawei/hinic/hinic_tx.c  |  4 +--
 drivers/net/ethernet/ibm/ibmveth.c            |  2 +-
 drivers/net/ethernet/ibm/ibmvnic.c            |  2 +-
 drivers/net/ethernet/intel/e1000/e1000_main.c |  2 +-
 drivers/net/ethernet/intel/e1000e/netdev.c    |  2 +-
 drivers/net/ethernet/intel/fm10k/fm10k_main.c |  2 +-
 drivers/net/ethernet/intel/igb/igb_main.c     |  2 +-
 drivers/net/ethernet/intel/igbvf/netdev.c     |  2 +-
 drivers/net/ethernet/intel/igc/igc_main.c     |  2 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  2 +-
 .../net/ethernet/intel/ixgbevf/ixgbevf_main.c |  2 +-
 drivers/net/ethernet/marvell/mv643xx_eth.c    |  2 +-
 .../net/ethernet/marvell/mvpp2/mvpp2_main.c   |  2 +-
 drivers/net/ethernet/marvell/skge.c           |  2 +-
 drivers/net/ethernet/marvell/sky2.c           | 10 +++----
 drivers/net/ethernet/mediatek/mtk_eth_soc.c   |  4 +--
 .../net/ethernet/mellanox/mlx5/core/en_tx.c   |  2 +-
 drivers/net/ethernet/mellanox/mlxsw/pci.c     |  2 +-
 drivers/net/ethernet/microchip/lan743x_main.c |  2 +-
 drivers/net/ethernet/neterion/s2io.c          |  2 +-
 .../net/ethernet/neterion/vxge/vxge-main.c    |  6 ++--
 drivers/net/ethernet/ni/nixge.c               |  2 +-
 drivers/net/ethernet/pasemi/pasemi_mac.c      |  2 +-
 .../ethernet/qlogic/netxen/netxen_nic_main.c  |  2 +-
 drivers/net/ethernet/qlogic/qed/qed_ll2.c     |  2 +-
 .../net/ethernet/qlogic/qlcnic/qlcnic_io.c    |  2 +-
 drivers/net/ethernet/realtek/8139cp.c         |  2 +-
 drivers/net/ethernet/rocker/rocker_main.c     |  2 +-
 drivers/net/ethernet/sfc/tx.c                 |  2 +-
 drivers/net/ethernet/sun/cassini.c            |  2 +-
 drivers/net/ethernet/sun/niu.c                |  4 +--
 drivers/net/ethernet/sun/sungem.c             |  2 +-
 drivers/net/ethernet/sun/sunhme.c             |  2 +-
 drivers/net/ethernet/sun/sunvnet_common.c     |  4 +--
 .../net/ethernet/synopsys/dwc-xlgmac-desc.c   |  2 +-
 .../net/ethernet/synopsys/dwc-xlgmac-net.c    |  2 +-
 drivers/net/ethernet/ti/am65-cpsw-nuss.c      |  2 +-
 drivers/net/ethernet/ti/netcp_core.c          |  2 +-
 drivers/net/ethernet/via/via-velocity.c       |  2 +-
 drivers/net/ethernet/xilinx/ll_temac_main.c   |  2 +-
 .../net/ethernet/xilinx/xilinx_axienet_main.c |  2 +-
 drivers/net/usb/usbnet.c                      |  2 +-
 drivers/net/vmxnet3/vmxnet3_drv.c             |  4 +--
 drivers/net/wireless/intel/iwlwifi/pcie/tx.c  |  2 +-
 drivers/net/wireless/intel/iwlwifi/queue/tx.c |  2 +-
 drivers/net/xen-netback/netback.c             |  2 +-
 drivers/net/xen-netfront.c                    |  2 +-
 drivers/s390/net/qeth_core_main.c             |  4 +--
 drivers/scsi/fcoe/fcoe_transport.c            |  2 +-
 drivers/staging/octeon/ethernet-tx.c          |  2 +-
 net/appletalk/ddp.c                           |  2 +-
 net/core/datagram.c                           |  4 +--
 net/core/skbuff.c                             | 30 +++++++++----------
 net/ipv4/inet_fragment.c                      |  2 +-
 net/ipv4/tcp_output.c                         |  2 +-
 net/iucv/af_iucv.c                            |  4 +--
 net/kcm/kcmsock.c                             |  3 +-
 net/tls/tls_sw.c                              |  2 +-
 94 files changed, 135 insertions(+), 137 deletions(-)

diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 47a02e60898d..7b3ae1a34dd5 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/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)
diff --git a/drivers/atm/he.c b/drivers/atm/he.c
index 17f44abc9418..2e606e255f7c 100644
--- a/drivers/atm/he.c
+++ b/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 */
diff --git a/drivers/hsi/clients/ssi_protocol.c b/drivers/hsi/clients/ssi_protocol.c
index 96d0eccca3aa..c697efd22cce 100644
--- a/drivers/hsi/clients/ssi_protocol.c
+++ b/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];
diff --git a/drivers/infiniband/hw/hfi1/ipoib_tx.c b/drivers/infiniband/hw/hfi1/ipoib_tx.c
index edd4eeac8dd1..b3f1c529e7ca 100644
--- a/drivers/infiniband/hw/hfi1/ipoib_tx.c
+++ b/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,
diff --git a/drivers/infiniband/hw/hfi1/vnic_sdma.c b/drivers/infiniband/hw/hfi1/vnic_sdma.c
index 7d90b900131b..dbdf3bc2ba2b 100644
--- a/drivers/infiniband/hw/hfi1/vnic_sdma.c
+++ b/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? */
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index d5d592bdab35..5ebb0d8ad864 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/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) {
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 494f413dc3c6..92636ac68a86 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/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],
diff --git a/drivers/net/ethernet/3com/3c59x.c b/drivers/net/ethernet/3com/3c59x.c
index 741c67e546d4..aadf232bd18f 100644
--- a/drivers/net/ethernet/3com/3c59x.c
+++ b/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,
diff --git a/drivers/net/ethernet/3com/typhoon.c b/drivers/net/ethernet/3com/typhoon.c
index 05e15b6e5e2c..f0f0c0135fa7 100644
--- a/drivers/net/ethernet/3com/typhoon.c
+++ b/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;
 
diff --git a/drivers/net/ethernet/adaptec/starfire.c b/drivers/net/ethernet/adaptec/starfire.c
index 555299737b51..7563bd3c4c72 100644
--- a/drivers/net/ethernet/adaptec/starfire.c
+++ b/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]),
diff --git a/drivers/net/ethernet/aeroflex/greth.c b/drivers/net/ethernet/aeroflex/greth.c
index 9c5891bbfe61..2af70152caa7 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/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;
 
diff --git a/drivers/net/ethernet/alteon/acenic.c b/drivers/net/ethernet/alteon/acenic.c
index 1a7e4df9b3e9..6607ba3b5b50 100644
--- a/drivers/net/ethernet/alteon/acenic.c
+++ b/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;
 
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 881f88754bf6..131f6fdc1786 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/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);
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-desc.c b/drivers/net/ethernet/amd/xgbe/xgbe-desc.c
index 230726d7b74f..9e496fe32ec6 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-desc.c
+++ b/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);
 
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index 4f714f874c4f..903947971d19 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/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++;
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index 5f1fc6582d74..82181da38683 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/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);
diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c
index 9e02f8864593..d38f4c5c34f3 100644
--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/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)
diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
index d54375b255dc..2de73fc38c44 100644
--- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+++ b/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);
diff --git a/drivers/net/ethernet/atheros/atl1e/atl1e_main.c b/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
index ff9f96de74b8..df96bba727fa 100644
--- a/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
+++ b/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;
diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
index eaf96d002fa5..fd893d8ba4fc 100644
--- a/drivers/net/ethernet/atheros/atlx/atl1.c
+++ b/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;
diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 075f6e146b29..1d72b8f2577d 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/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);
 
diff --git a/drivers/net/ethernet/broadcom/bnx2.c b/drivers/net/ethernet/broadcom/bnx2.c
index 3e8a179f39db..c2800641f32d 100644
--- a/drivers/net/ethernet/broadcom/bnx2.c
+++ b/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);
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 1a6ec1a12d53..208c75691388 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/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,
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 6f13642121c4..5495cf8f4db3 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/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),
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index d2381929931b..e167131697fc 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/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;
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index f56f3dbbc015..2c2e2de60894 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/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);
 	}
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index f782e6af45e9..dce6ca7694f0 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/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);
diff --git a/drivers/net/ethernet/chelsio/cxgb3/sge.c b/drivers/net/ethernet/chelsio/cxgb3/sge.c
index 1cc3c51eff71..b0e107363ec4 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/sge.c
+++ b/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);
 }
diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index b6eba29d8e99..ad4acfd36d8d 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/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);
 
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 04421aec2dfd..711af29d9a6a 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/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);
diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index 177c020bf34a..b3aa4c9dc03a 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/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 */
diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 1cf8ef717453..bbe91cf9fc1d 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/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);
diff --git a/drivers/net/ethernet/hisilicon/hix5hd2_gmac.c b/drivers/net/ethernet/hisilicon/hix5hd2_gmac.c
index 8b2bf85039f1..eb1999309bad 100644
--- a/drivers/net/ethernet/hisilicon/hix5hd2_gmac.c
+++ b/drivers/net/ethernet/hisilicon/hix5hd2_gmac.c
@@ -577,7 +577,7 @@ static void hix5hd2_clean_sg_desc(struct hix5hd2_priv *priv,
 	len = le32_to_cpu(desc->linear_len);
 	dma_unmap_single(priv->dev, addr, len, DMA_TO_DEVICE);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		addr = le32_to_cpu(desc->frags[i].addr);
 		len = le32_to_cpu(desc->frags[i].size);
 		dma_unmap_page(priv->dev, addr, len, DMA_TO_DEVICE);
@@ -717,7 +717,7 @@ static int hix5hd2_fill_sg_desc(struct hix5hd2_priv *priv,
 	desc->linear_addr = cpu_to_le32(addr);
 	desc->linear_len = 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];
 		int len = skb_frag_size(frag);
 
diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index 5e349c0bdecc..de5bc35b7363 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -252,7 +252,7 @@ static int hns_nic_maybe_stop_tso(
 	buf_num = (size + BD_MAX_SEND_SIZE - 1) / BD_MAX_SEND_SIZE;
 
 	frag_num = skb_shinfo(skb)->nr_frags;
-	for (i = 0; i < frag_num; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 		size = skb_frag_size(frag);
 		buf_num += (size + BD_MAX_SEND_SIZE - 1) / BD_MAX_SEND_SIZE;
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 25afe5a3348c..f0fc115b48d2 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -1257,7 +1257,7 @@ static unsigned int hns3_skb_bd_num(struct sk_buff *skb, unsigned int *bd_size,
 			return bd_num;
 	}
 
-	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];
 		size = skb_frag_size(frag);
 		if (!size)
@@ -1507,7 +1507,7 @@ static int hns3_fill_skb_to_desc(struct hns3_enet_ring *ring,
 		bd_num += ret;
 	}
 
-	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];
 
 		size = skb_frag_size(frag);
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_rx.c b/drivers/net/ethernet/huawei/hinic/hinic_rx.c
index cce08647b9b2..62a349ea3c4c 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_rx.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_rx.c
@@ -336,7 +336,7 @@ static void hinic_copy_lp_data(struct hinic_dev *nic_dev,
 	frag_len = (int)skb_headlen(skb);
 	memcpy(lb_buf + pkt_offset, skb->data, frag_len);
 	pkt_offset += frag_len;
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag_data = skb_frag_address(&skb_shinfo(skb)->frags[i]);
 		frag_len = (int)skb_frag_size(&skb_shinfo(skb)->frags[i]);
 		memcpy((lb_buf + pkt_offset), frag_data, frag_len);
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_tx.c b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
index 710c4ff7bc0e..f30f6ff3bbfd 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_tx.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
@@ -149,7 +149,7 @@ static int tx_map_skb(struct hinic_dev *nic_dev, struct sk_buff *skb,
 
 	hinic_set_sge(&sges[0], dma_addr, skb_headlen(skb));
 
-	for (i = 0 ; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 
 		dma_addr = skb_frag_dma_map(&pdev->dev, frag, 0,
@@ -189,7 +189,7 @@ static void tx_unmap_skb(struct hinic_dev *nic_dev, struct sk_buff *skb,
 	struct pci_dev *pdev = hwif->pdev;
 	int i;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags ; i++)
+	skb_for_each_frag(skb, i)
 		dma_unmap_page(&pdev->dev, hinic_sge_to_dma(&sges[i + 1]),
 			       sges[i + 1].len, DMA_TO_DEVICE);
 
diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 7fea9ae60f13..92e6cb9b5a3f 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1132,7 +1132,7 @@ static netdev_tx_t ibmveth_start_xmit(struct sk_buff *skb,
 	descs[0].fields.address = dma_addr;
 
 	/* Map the frags */
-	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];
 
 		dma_addr = skb_frag_dma_map(&adapter->vdev->dev, frag, 0,
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 473411542911..c884a7b83c81 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1675,7 +1675,7 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		cur = skb_headlen(skb);
 
 		/* Copy the frags */
-		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];
 
 			memcpy(dst + cur, skb_frag_address(frag),
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 042de276e632..0dd697b359c9 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -3193,7 +3193,7 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
 		count++;
 
 	nr_frags = skb_shinfo(skb)->nr_frags;
-	for (f = 0; f < nr_frags; f++)
+	skb_for_each_frag(skb, f)
 		count += TXD_USE_COUNT(skb_frag_size(&skb_shinfo(skb)->frags[f]),
 				       max_txd_pwr);
 	if (adapter->pcix_82544)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 88e9035b75cf..3a5443330b4a 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5870,7 +5870,7 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
 	count += DIV_ROUND_UP(len, adapter->tx_fifo_limit);
 
 	nr_frags = skb_shinfo(skb)->nr_frags;
-	for (f = 0; f < nr_frags; f++)
+	skb_for_each_frag(skb, f)
 		count += DIV_ROUND_UP(skb_frag_size(&skb_shinfo(skb)->frags[f]),
 				      adapter->tx_fifo_limit);
 
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index 3362f26d7f99..f103e9b406e4 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
@@ -1055,7 +1055,7 @@ netdev_tx_t fm10k_xmit_frame_ring(struct sk_buff *skb,
 	 *       + 2 desc gap to keep tail from touching head
 	 * otherwise try next time
 	 */
-	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];
 
 		count += TXD_USE_COUNT(skb_frag_size(frag));
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index c9e8c65a3cfe..4103252f5a9b 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6324,7 +6324,7 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 	 *       + 1 desc for context descriptor,
 	 * otherwise try next time
 	 */
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+	skb_for_each_frag(skb, f)
 		count += TXD_USE_COUNT(skb_frag_size(
 						&skb_shinfo(skb)->frags[f]));
 
diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c
index fb3fbcb13331..12a54a33e836 100644
--- a/drivers/net/ethernet/intel/igbvf/netdev.c
+++ b/drivers/net/ethernet/intel/igbvf/netdev.c
@@ -2165,7 +2165,7 @@ static inline int igbvf_tx_map_adv(struct igbvf_adapter *adapter,
 	if (dma_mapping_error(&pdev->dev, buffer_info->dma))
 		goto dma_error;
 
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) {
+	skb_for_each_frag(skb, f) {
 		const skb_frag_t *frag;
 
 		count++;
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 10765491e357..f8613de9b1d2 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -1348,7 +1348,7 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb,
 	 *	+ 1 desc for context descriptor,
 	 * otherwise try next time
 	 */
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+	skb_for_each_frag(skb, f)
 		count += TXD_USE_COUNT(skb_frag_size(
 						&skb_shinfo(skb)->frags[f]));
 
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 7ba1c2985ef7..1b7fc29044f5 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -8602,7 +8602,7 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
 	 *       + 1 desc for context descriptor,
 	 * otherwise try next time
 	 */
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+	skb_for_each_frag(skb, f)
 		count += TXD_USE_COUNT(skb_frag_size(
 						&skb_shinfo(skb)->frags[f]));
 
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index ba2ed8a43d2d..904304305684 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -4127,7 +4127,7 @@ static int ixgbevf_xmit_frame_ring(struct sk_buff *skb,
 	 * otherwise try next time
 	 */
 #if PAGE_SIZE > IXGBE_MAX_DATA_PER_TXD
-	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];
 
 		count += TXD_USE_COUNT(skb_frag_size(frag));
diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
index ca1681aa951a..4a8a2ae7d4b9 100644
--- a/drivers/net/ethernet/marvell/mv643xx_eth.c
+++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
@@ -656,7 +656,7 @@ static inline unsigned int has_tiny_unaligned_frags(struct sk_buff *skb)
 {
 	int frag;
 
-	for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
+	skb_for_each_frag(skb, frag) {
 		const skb_frag_t *fragp = &skb_shinfo(skb)->frags[frag];
 
 		if (skb_frag_size(fragp) <= 8 && skb_frag_off(fragp) & 7)
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index ec706d614cac..72c0aece18eb 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -4129,7 +4129,7 @@ static int mvpp2_tx_frag_process(struct mvpp2_port *port, struct sk_buff *skb,
 	int i;
 	dma_addr_t buf_dma_addr;
 
-	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];
 		void *addr = skb_frag_address(frag);
 
diff --git a/drivers/net/ethernet/marvell/skge.c b/drivers/net/ethernet/marvell/skge.c
index d4bb27ba1419..f9e3952ed1e8 100644
--- a/drivers/net/ethernet/marvell/skge.c
+++ b/drivers/net/ethernet/marvell/skge.c
@@ -2786,7 +2786,7 @@ static netdev_tx_t skge_xmit_frame(struct sk_buff *skb,
 		struct skge_tx_desc *tf = td;
 
 		control |= BMU_STFWD;
-		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];
 
 			map = skb_frag_dma_map(&hw->pdev->dev, frag, 0,
diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
index 68c154d715d6..f5dfc86026c2 100644
--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -1199,7 +1199,7 @@ static void sky2_rx_submit(struct sky2_port *sky2,
 
 	sky2_rx_add(sky2, OP_PACKET, re->data_addr, sky2->rx_data_size);
 
-	for (i = 0; i < skb_shinfo(re->skb)->nr_frags; i++)
+	skb_for_each_frag(re->skb, i)
 		sky2_rx_add(sky2, OP_BUFFER, re->frag_addr[i], PAGE_SIZE);
 }
 
@@ -1217,7 +1217,7 @@ static int sky2_rx_map_skb(struct pci_dev *pdev, struct rx_ring_info *re,
 
 	dma_unmap_len_set(re, data_size, size);
 
-	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];
 
 		re->frag_addr[i] = skb_frag_dma_map(&pdev->dev, frag, 0,
@@ -1254,7 +1254,7 @@ static void sky2_rx_unmap_skb(struct pci_dev *pdev, struct rx_ring_info *re)
 	dma_unmap_single(&pdev->dev, re->data_addr,
 			 dma_unmap_len(re, data_size), DMA_FROM_DEVICE);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+	skb_for_each_frag(skb, i)
 		dma_unmap_page(&pdev->dev, re->frag_addr[i],
 			       skb_frag_size(&skb_shinfo(skb)->frags[i]),
 			       DMA_FROM_DEVICE);
@@ -1932,7 +1932,7 @@ static netdev_tx_t sky2_xmit_frame(struct sk_buff *skb,
 	le->opcode = mss ? (OP_LARGESEND | HW_OWNER) : (OP_PACKET | HW_OWNER);
 
 
-	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 = skb_frag_dma_map(&hw->pdev->dev, frag, 0,
@@ -2498,7 +2498,7 @@ 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) {
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 810def064f11..eca33743aefe 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -972,7 +972,7 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
 	txd_pdma = qdma_to_pdma(ring, txd);
 	nr_frags = skb_shinfo(skb)->nr_frags;
 
-	for (i = 0; i < nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		unsigned int offset = 0;
 		int frag_size = skb_frag_size(frag);
@@ -1089,7 +1089,7 @@ static inline int mtk_cal_txd_req(struct sk_buff *skb)
 
 	nfrags = 1;
 	if (skb_is_gso(skb)) {
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			frag = &skb_shinfo(skb)->frags[i];
 			nfrags += DIV_ROUND_UP(skb_frag_size(frag),
 						MTK_TX_DMA_BUF_LEN);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 8ba62671f5f1..9aa45fe5c74d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -320,7 +320,7 @@ mlx5e_txwqe_build_dsegs(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 		dseg++;
 	}
 
-	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];
 		int fsz = skb_frag_size(frag);
 
diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
index 8e8456811384..0a6842f8e285 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/pci.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c
@@ -1692,7 +1692,7 @@ static int mlxsw_pci_skb_transmit(void *bus_priv, struct sk_buff *skb,
 	if (err)
 		goto unlock;
 
-	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];
 
 		err = mlxsw_pci_wqe_frag_map(mlxsw_pci, wqe, i + 1,
diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index e7ab5f3f73fd..2d63b42a3fca 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -1640,7 +1640,7 @@ static netdev_tx_t lan743x_tx_xmit_frame(struct lan743x_tx *tx,
 	if (nr_frags <= 0)
 		goto finish;
 
-	for (j = 0; j < nr_frags; j++) {
+	skb_for_each_frag(skb, j) {
 		const skb_frag_t *frag = &(skb_shinfo(skb)->frags[j]);
 
 		if (lan743x_tx_frame_add_fragment(tx, frag, frame_length)) {
diff --git a/drivers/net/ethernet/neterion/s2io.c b/drivers/net/ethernet/neterion/s2io.c
index 9cfcd5500462..e1ad58ef5fbc 100644
--- a/drivers/net/ethernet/neterion/s2io.c
+++ b/drivers/net/ethernet/neterion/s2io.c
@@ -4132,7 +4132,7 @@ static netdev_tx_t s2io_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	frg_cnt = skb_shinfo(skb)->nr_frags;
 	/* For fragmented SKB. */
-	for (i = 0; i < frg_cnt; i++) {
+	skb_for_each_frag(skb, i) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		/* A '0' length fragment will be ignored */
 		if (!skb_frag_size(frag))
diff --git a/drivers/net/ethernet/neterion/vxge/vxge-main.c b/drivers/net/ethernet/neterion/vxge/vxge-main.c
index 87892bd992b1..71991116fa94 100644
--- a/drivers/net/ethernet/neterion/vxge/vxge-main.c
+++ b/drivers/net/ethernet/neterion/vxge/vxge-main.c
@@ -589,7 +589,7 @@ vxge_xmit_compl(struct __vxge_hw_fifo *fifo_hw, void *dtr,
 		dma_unmap_single(&fifo->pdev->dev, txd_priv->dma_buffers[i++],
 				 skb_headlen(skb), DMA_TO_DEVICE);
 
-		for (j = 0; j < frg_cnt; j++) {
+		skb_for_each_frag(skb, j) {
 			dma_unmap_page(&fifo->pdev->dev,
 				       txd_priv->dma_buffers[i++],
 				       skb_frag_size(frag), DMA_TO_DEVICE);
@@ -922,7 +922,7 @@ vxge_xmit(struct sk_buff *skb, struct net_device *dev)
 		first_frg_len);
 
 	frag = &skb_shinfo(skb)->frags[0];
-	for (i = 0; i < frg_cnt; i++) {
+	skb_for_each_frag(skb, i) {
 		/* ignore 0 length fragment */
 		if (!skb_frag_size(frag))
 			continue;
@@ -1052,7 +1052,7 @@ vxge_tx_term(void *dtrh, enum vxge_hw_txdl_state state, void *userdata)
 	dma_unmap_single(&fifo->pdev->dev, txd_priv->dma_buffers[i++],
 			 skb_headlen(skb), DMA_TO_DEVICE);
 
-	for (j = 0; j < frg_cnt; j++) {
+	skb_for_each_frag(skb, j) {
 		dma_unmap_page(&fifo->pdev->dev, txd_priv->dma_buffers[i++],
 			       skb_frag_size(frag), DMA_TO_DEVICE);
 		frag += 1;
diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c
index a6861df9904f..980a57e373d3 100644
--- a/drivers/net/ethernet/ni/nixge.c
+++ b/drivers/net/ethernet/ni/nixge.c
@@ -536,7 +536,7 @@ static netdev_tx_t nixge_start_xmit(struct sk_buff *skb,
 	tx_skb->size = skb_headlen(skb);
 	tx_skb->mapped_as_page = false;
 
-	for (ii = 0; ii < num_frag; ii++) {
+	skb_for_each_frag(skb, ii) {
 		++priv->tx_bd_tail;
 		priv->tx_bd_tail %= TX_BD_NUM;
 		cur_p = &priv->tx_bd_v[priv->tx_bd_tail];
diff --git a/drivers/net/ethernet/pasemi/pasemi_mac.c b/drivers/net/ethernet/pasemi/pasemi_mac.c
index 040a15a828b4..fbf3a227fe03 100644
--- a/drivers/net/ethernet/pasemi/pasemi_mac.c
+++ b/drivers/net/ethernet/pasemi/pasemi_mac.c
@@ -1450,7 +1450,7 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
 	if (pci_dma_mapping_error(mac->dma_pdev, map[0]))
 		goto out_err_nolock;
 
-	for (i = 0; i < nfrags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
 		map[i + 1] = skb_frag_dma_map(&mac->dma_pdev->dev, frag, 0,
diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
index 7e6bac85495d..39ae5af77220 100644
--- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
+++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
@@ -1986,7 +1986,7 @@ netxen_map_tx_skb(struct pci_dev *pdev,
 	nf->dma = map;
 	nf->length = skb_headlen(skb);
 
-	for (i = 0; i < nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 		nf = &pbuf->frag_array[i+1];
 
diff --git a/drivers/net/ethernet/qlogic/qed/qed_ll2.c b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
index 49783f365079..8ac7d8b8ac24 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_ll2.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
@@ -2666,7 +2666,7 @@ static int qed_ll2_start_xmit(struct qed_dev *cdev, struct sk_buff *skb,
 	if (rc)
 		goto err;
 
-	for (i = 0; i < nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 
 		mapping = skb_frag_dma_map(&cdev->pdev->dev, frag, 0,
diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c
index bdf15d2a6431..a6b6845e2a2f 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c
@@ -595,7 +595,7 @@ static int qlcnic_map_tx_skb(struct pci_dev *pdev, struct sk_buff *skb,
 	nf->dma = map;
 	nf->length = skb_headlen(skb);
 
-	for (i = 0; i < nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 		nf = &pbuf->frag_array[i+1];
 		map = skb_frag_dma_map(&pdev->dev, frag, 0, skb_frag_size(frag),
diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c
index 4e44313b7651..787ca2b76912 100644
--- a/drivers/net/ethernet/realtek/8139cp.c
+++ b/drivers/net/ethernet/realtek/8139cp.c
@@ -816,7 +816,7 @@ static netdev_tx_t cp_start_xmit (struct sk_buff *skb,
 
 		cp->tx_skb[entry] = skb;
 
-		for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
+		skb_for_each_frag(skb, frag) {
 			const skb_frag_t *this_frag = &skb_shinfo(skb)->frags[frag];
 			u32 len;
 			dma_addr_t mapping;
diff --git a/drivers/net/ethernet/rocker/rocker_main.c b/drivers/net/ethernet/rocker/rocker_main.c
index 3473d296b2e2..758481bd3df1 100644
--- a/drivers/net/ethernet/rocker/rocker_main.c
+++ b/drivers/net/ethernet/rocker/rocker_main.c
@@ -1910,7 +1910,7 @@ static netdev_tx_t rocker_port_xmit(struct sk_buff *skb, struct net_device *dev)
 			goto unmap_frags;
 	}
 
-	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];
 
 		err = rocker_tx_desc_frag_map_put(rocker_port, desc_info,
diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 0c6650d2e239..4ef172df08b9 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -203,7 +203,7 @@ static void efx_skb_copy_bits_to_pio(struct efx_nic *efx, struct sk_buff *skb,
 	efx_memcpy_toio_aligned(efx, piobuf, skb->data, skb_headlen(skb),
 				copy_buf);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 		u8 *vaddr;
 
diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index 54f45d8c79a7..8924388389c1 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -2796,7 +2796,7 @@ static inline int cas_xmit_tx_ringN(struct cas *cp, int ring,
 	}
 	entry = TX_DESC_NEXT(ring, entry);
 
-	for (frag = 0; frag < nr_frags; frag++) {
+	skb_for_each_frag(skb, frag) {
 		const skb_frag_t *fragp = &skb_shinfo(skb)->frags[frag];
 
 		len = skb_frag_size(fragp);
diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index 707ccdd03b19..920c29955172 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -3565,7 +3565,7 @@ static int release_tx_packet(struct niu *np, struct tx_ring_info *rp, int idx)
 		len -= MAX_TX_DESC_LEN;
 	} while (len > 0);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		tb = &rp->tx_buffs[idx];
 		BUG_ON(tb->skb != NULL);
 		np->ops->unmap_page(np->device, tb->mapping,
@@ -6688,7 +6688,7 @@ static netdev_tx_t niu_start_xmit(struct sk_buff *skb,
 		len -= this_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);
diff --git a/drivers/net/ethernet/sun/sungem.c b/drivers/net/ethernet/sun/sungem.c
index 9790656cf970..76cd9569de18 100644
--- a/drivers/net/ethernet/sun/sungem.c
+++ b/drivers/net/ethernet/sun/sungem.c
@@ -1054,7 +1054,7 @@ static netdev_tx_t gem_start_xmit(struct sk_buff *skb,
 					     first_len, DMA_TO_DEVICE);
 		entry = NEXT_TX(entry);
 
-		for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
+		skb_for_each_frag(skb, frag) {
 			const skb_frag_t *this_frag = &skb_shinfo(skb)->frags[frag];
 			u32 len;
 			dma_addr_t mapping;
diff --git a/drivers/net/ethernet/sun/sunhme.c b/drivers/net/ethernet/sun/sunhme.c
index 54b53dbdb33c..8faed52e5304 100644
--- a/drivers/net/ethernet/sun/sunhme.c
+++ b/drivers/net/ethernet/sun/sunhme.c
@@ -2339,7 +2339,7 @@ static netdev_tx_t happy_meal_start_xmit(struct sk_buff *skb,
 			goto out_dma_error;
 		entry = NEXT_TX(entry);
 
-		for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
+		skb_for_each_frag(skb, frag) {
 			const skb_frag_t *this_frag = &skb_shinfo(skb)->frags[frag];
 			u32 len, mapping, this_txflags;
 
diff --git a/drivers/net/ethernet/sun/sunvnet_common.c b/drivers/net/ethernet/sun/sunvnet_common.c
index 80fde5f06fce..15056f84b4ae 100644
--- a/drivers/net/ethernet/sun/sunvnet_common.c
+++ b/drivers/net/ethernet/sun/sunvnet_common.c
@@ -1080,7 +1080,7 @@ static inline int vnet_skb_map(struct ldc_channel *lp, struct sk_buff *skb,
 		return err;
 	nc = err;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 		u8 *vaddr;
 
@@ -1121,7 +1121,7 @@ static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, int ncookies)
 
 	/* make sure we have enough cookies and alignment in every frag */
 	docopy = skb_shinfo(skb)->nr_frags >= ncookies;
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 
 		docopy |= skb_frag_off(f) & 7;
diff --git a/drivers/net/ethernet/synopsys/dwc-xlgmac-desc.c b/drivers/net/ethernet/synopsys/dwc-xlgmac-desc.c
index 589797bad1f9..360b3f1458d5 100644
--- a/drivers/net/ethernet/synopsys/dwc-xlgmac-desc.c
+++ b/drivers/net/ethernet/synopsys/dwc-xlgmac-desc.c
@@ -576,7 +576,7 @@ static int xlgmac_map_tx_skb(struct xlgmac_channel *channel,
 		desc_data = XLGMAC_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);
 
diff --git a/drivers/net/ethernet/synopsys/dwc-xlgmac-net.c b/drivers/net/ethernet/synopsys/dwc-xlgmac-net.c
index 26d178f8616b..c50223b77b1e 100644
--- a/drivers/net/ethernet/synopsys/dwc-xlgmac-net.c
+++ b/drivers/net/ethernet/synopsys/dwc-xlgmac-net.c
@@ -177,7 +177,7 @@ static void xlgmac_prep_tx_pkt(struct xlgmac_pdata *pdata,
 		len -= min_t(unsigned int, len, XLGMAC_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; ) {
 			pkt_info->desc_count++;
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 638d7b03be4b..31038cd4c251 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -1183,7 +1183,7 @@ static netdev_tx_t am65_cpsw_nuss_ndo_slave_xmit(struct sk_buff *skb,
 
 	/* Handle the case where skb is fragmented in pages */
 	cur_desc = first_desc;
-	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];
 		u32 frag_size = skb_frag_size(frag);
 
diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
index d7a144b4a09f..512e4455b5ee 100644
--- a/drivers/net/ethernet/ti/netcp_core.c
+++ b/drivers/net/ethernet/ti/netcp_core.c
@@ -1113,7 +1113,7 @@ netcp_tx_map_skb(struct sk_buff *skb, struct netcp_intf *netcp)
 	pdesc = desc;
 
 	/* Handle the case where skb is fragmented in pages */
-	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];
 		struct page *page = skb_frag_page(frag);
 		u32 page_offset = skb_frag_off(frag);
diff --git a/drivers/net/ethernet/via/via-velocity.c b/drivers/net/ethernet/via/via-velocity.c
index fecc4d7b00b0..02c869bcecc4 100644
--- a/drivers/net/ethernet/via/via-velocity.c
+++ b/drivers/net/ethernet/via/via-velocity.c
@@ -2576,7 +2576,7 @@ static netdev_tx_t velocity_xmit(struct sk_buff *skb,
 	td_ptr->td_buf[0].size = cpu_to_le16(pktlen);
 
 	/* Handle fragments */
-	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];
 
 		tdinfo->skb_dma[i + 1] = skb_frag_dma_map(vptr->dev,
diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 030185301014..2eb5c83b54ba 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -878,7 +878,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	cur_p->phys = cpu_to_be32(skb_dma_addr);
 	ptr_to_txbd((void *)skb, cur_p);
 
-	for (ii = 0; ii < num_frag; ii++) {
+	skb_for_each_frag(skb, ii) {
 		if (++lp->tx_bd_tail >= lp->tx_bd_num)
 			lp->tx_bd_tail = 0;
 
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 92cf9051d557..cfc74371a7ea 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -772,7 +772,7 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	desc_set_phys_addr(lp, phys, cur_p);
 	cur_p->cntrl = skb_headlen(skb) | XAXIDMA_BD_CTRL_TXSOF_MASK;
 
-	for (ii = 0; ii < num_frag; ii++) {
+	skb_for_each_frag(skb, ii) {
 		if (++lp->tx_bd_tail >= lp->tx_bd_num)
 			lp->tx_bd_tail = 0;
 		cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index ecf62849f4c1..465b9926d3da 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1321,7 +1321,7 @@ static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
 	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
 	total_len += skb_headlen(skb);
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 
 		total_len += skb_frag_size(f);
diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 6e87f1fc4874..cc06b9257a15 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -747,7 +747,7 @@ vmxnet3_map_pkt(struct sk_buff *skb, struct vmxnet3_tx_ctx *ctx,
 		buf_offset += buf_size;
 	}
 
-	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];
 		u32 buf_size;
 
@@ -990,7 +990,7 @@ static int txd_estimate(const struct sk_buff *skb)
 	int count = VMXNET3_TXD_NEEDED(skb_headlen(skb)) + 1;
 	int i;
 
-	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];
 
 		count += VMXNET3_TXD_NEEDED(skb_frag_size(frag));
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
index 381e8f90b6f2..2b9dbf59ff05 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
@@ -1277,7 +1277,7 @@ static int iwl_fill_data_tbs(struct iwl_trans *trans, struct sk_buff *skb,
 	}
 
 	/* set up the remaining entries to point to the data */
-	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];
 		dma_addr_t tb_phys;
 		int tb_idx;
diff --git a/drivers/net/wireless/intel/iwlwifi/queue/tx.c b/drivers/net/wireless/intel/iwlwifi/queue/tx.c
index 833f43d1ca7a..7629764c44fb 100644
--- a/drivers/net/wireless/intel/iwlwifi/queue/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/queue/tx.c
@@ -544,7 +544,7 @@ static int iwl_txq_gen2_tx_add_frags(struct iwl_trans *trans,
 {
 	int i;
 
-	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];
 		dma_addr_t tb_phys;
 		unsigned int fragsz = skb_frag_size(frag);
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 39a01c2a3058..85981635b8e5 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1086,7 +1086,7 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s
 	}
 
 	/* Release all the original (foreign) frags. */
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+	skb_for_each_frag(skb, f)
 		skb_frag_unref(skb, f);
 	uarg = skb_shinfo(skb)->destructor_arg;
 	/* increase inflight counter to offset decrement in callback */
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 44275908d61a..8388d48e2fda 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -744,7 +744,7 @@ static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev
 	tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
 
 	/* Requests for all the frags. */
-	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];
 		tx = xennet_make_txreqs(queue, tx, skb, skb_frag_page(frag),
 					skb_frag_off(frag),
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 6954d4e831a3..b069f67625bc 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -3939,7 +3939,7 @@ static int qeth_get_elements_for_frags(struct sk_buff *skb)
 {
 	int cnt, elements = 0;
 
-	for (cnt = 0; cnt < skb_shinfo(skb)->nr_frags; cnt++) {
+	skb_for_each_frag(skb, cnt) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[cnt];
 
 		elements += qeth_get_elements_for_range(
@@ -4152,7 +4152,7 @@ static unsigned int qeth_fill_buffer(struct qeth_qdio_out_buffer *buf,
 	}
 
 	/* map page frags into buffer element(s) */
-	for (cnt = 0; cnt < skb_shinfo(skb)->nr_frags; cnt++) {
+	skb_for_each_frag(skb, cnt) {
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[cnt];
 
 		data = skb_frag_address(frag);
diff --git a/drivers/scsi/fcoe/fcoe_transport.c b/drivers/scsi/fcoe/fcoe_transport.c
index b927b3d84523..6a1d3d31b9a3 100644
--- a/drivers/scsi/fcoe/fcoe_transport.c
+++ b/drivers/scsi/fcoe/fcoe_transport.c
@@ -317,7 +317,7 @@ u32 fcoe_fc_crc(struct fc_frame *fp)
 
 	crc = crc32(~0, skb->data, skb_headlen(skb));
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		frag = &skb_shinfo(skb)->frags[i];
 		off = skb_frag_off(frag);
 		len = skb_frag_size(frag);
diff --git a/drivers/staging/octeon/ethernet-tx.c b/drivers/staging/octeon/ethernet-tx.c
index 9c71ad5af7b9..c8e0fb76bdf4 100644
--- a/drivers/staging/octeon/ethernet-tx.c
+++ b/drivers/staging/octeon/ethernet-tx.c
@@ -269,7 +269,7 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
 		hw_buffer.s.pool = 0;
 		hw_buffer.s.size = skb_headlen(skb);
 		CVM_OCT_SKB_CB(skb)[0] = hw_buffer.u64;
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			skb_frag_t *fs = skb_shinfo(skb)->frags + i;
 
 			hw_buffer.s.addr =
diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index ebda397fa95a..7438211cb9c0 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -949,7 +949,7 @@ static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
 	}
 
 	/* checksum stuff in frags */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		WARN_ON(start > offset + len);
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 15ab9ffb27fe..8cd7bbf717df 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -432,7 +432,7 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
 	}
 
 	/* Copy paged appendix. Hmm... why does this look so complicated? */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
@@ -564,7 +564,7 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
 	}
 
 	/* Copy paged appendix. Hmm... why does this look so complicated? */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3ad9e8425ab2..062bbfeacc43 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1623,7 +1623,7 @@ struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
 			n = NULL;
 			goto out;
 		}
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_for_each_frag(skb, i) {
 			skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
 			skb_frag_ref(skb, i);
 		}
@@ -1698,7 +1698,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 			goto nofrags;
 		if (skb_zcopy(skb))
 			refcount_inc(&skb_uarg(skb)->refcnt);
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+		skb_for_each_frag(skb, i)
 			skb_frag_ref(skb, i);
 
 		if (skb_has_frag_list(skb))
@@ -2126,7 +2126,7 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta)
 
 	/* Estimate size of pulled pages. */
 	eat = delta;
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
 
 		if (size >= eat)
@@ -2191,7 +2191,7 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta)
 pull_pages:
 	eat = delta;
 	k = 0;
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
 
 		if (size <= eat) {
@@ -2259,7 +2259,7 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
 		to     += copy;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 
@@ -2447,7 +2447,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
 	/*
 	 * then map the fragments
 	 */
-	for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
+	skb_for_each_frag(skb, seg) {
 		const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
 
 		if (__splice_segment(skb_frag_page(f),
@@ -2562,7 +2562,7 @@ static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
 	offset -= skb_headlen(skb);
 
 	/* Find where we are in frag list */
-	for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
+	skb_for_each_frag(skb, fragidx) {
 		skb_frag_t *frag  = &skb_shinfo(skb)->frags[fragidx];
 
 		if (offset < skb_frag_size(frag))
@@ -2661,7 +2661,7 @@ int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
 		from += copy;
 	}
 
-	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];
 		int end;
 
@@ -2740,7 +2740,7 @@ __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
 		pos	= copy;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
@@ -2840,7 +2840,7 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
 		pos	= copy;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 
 		WARN_ON(start > offset + len);
@@ -3072,7 +3072,7 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
 	}
 	skb_zerocopy_clone(to, from, GFP_ATOMIC);
 
-	for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
+	skb_for_each_frag(from, i) {
 		int size;
 
 		if (!len)
@@ -3292,7 +3292,7 @@ static inline void skb_split_inside_header(struct sk_buff *skb,
 	skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
 					 pos - len);
 	/* And move data appendix as is. */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+	skb_for_each_frag(skb, i)
 		skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
 
 	skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
@@ -4419,7 +4419,7 @@ __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len,
 		offset += copy;
 	}
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int end;
 
 		WARN_ON(start > offset + len);
@@ -5329,7 +5329,7 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 	/* if the skb is not cloned this does nothing
 	 * since we set nr_frags to 0.
 	 */
-	for (i = 0; i < from_shinfo->nr_frags; i++)
+	skb_for_each_frag(from, i)
 		__skb_frag_ref(&from_shinfo->frags[i]);
 
 	to->truesize += delta;
@@ -6053,7 +6053,7 @@ static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
 			kfree(data);
 			return -ENOMEM;
 		}
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+		skb_for_each_frag(skb, i)
 			skb_frag_ref(skb, i);
 		if (skb_has_frag_list(skb))
 			skb_clone_fraglist(skb);
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 05cd198d7a6b..4837411c7374 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -487,7 +487,7 @@ void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 			return NULL;
 		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 		skb_frag_list_init(head);
-		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
+		skb_for_each_frag(head, i)
 			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 		clone->data_len = head->data_len - plen;
 		clone->len = clone->data_len;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index bde781f46b41..5de00477eaf9 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1644,7 +1644,7 @@ static int __pskb_trim_head(struct sk_buff *skb, int len)
 	eat = len;
 	k = 0;
 	shinfo = skb_shinfo(skb);
-	for (i = 0; i < shinfo->nr_frags; i++) {
+	skb_for_each_frag(skb, i) {
 		int size = skb_frag_size(&shinfo->frags[i]);
 
 		if (size <= eat) {
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 0fdb389c3390..33b0e96a2b91 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1079,7 +1079,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
 			/* skip iucv_array lying in the headroom */
 			iba[0].address = (u32)(addr_t)skb->data;
 			iba[0].length = (u32)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];
 
 				iba[i + 1].address =
@@ -1181,7 +1181,7 @@ static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
 
 			iba[0].address = (u32)(addr_t)skb->data;
 			iba[0].length = (u32)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];
 
 				iba[i + 1].address =
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 6201965bd822..e1e149539ddb 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -630,8 +630,7 @@ static int kcm_write_msgs(struct kcm_sock *kcm)
 			goto out;
 		}
 
-		for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags;
-		     fragidx++) {
+		skb_for_each_frag(skb, fragidx) {
 			skb_frag_t *frag;
 
 			frag_offset = 0;
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 1dcb34dfd56b..661f4084080b 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -63,7 +63,7 @@ static int __skb_nsg(struct sk_buff *skb, int offset, int len,
                 offset += chunk;
         }
 
-        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+        skb_for_each_frag(skb, i) {
                 int end;
 
                 WARN_ON(start > offset + len);
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH net-next 3/3] net: use skb_for_each_frag() in illegal_highdma()
  2021-04-09 18:06 [PATCH net-next 0/3] introduce skb_for_each_frag() Matteo Croce
  2021-04-09 18:06 ` [PATCH net-next 1/3] skbuff: add helper to walk over the fraglist Matteo Croce
  2021-04-09 18:06 ` [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible Matteo Croce
@ 2021-04-09 18:06 ` Matteo Croce
  2 siblings, 0 replies; 10+ messages in thread
From: Matteo Croce @ 2021-04-09 18:06 UTC (permalink / raw)
  To: netdev; +Cc: linux-kernel, David S. Miller, Jakub Kicinski, Julia Lawall

From: Matteo Croce <mcroce@microsoft.com>

Coccinelle failed with the following error:

 EXN: Failure("no position information") in net/core/dev.c

Apply it by hand as it's trivial.

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 33ff4a944109..98deb4852151 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3505,7 +3505,7 @@ static int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 	int i;
 
 	if (!(dev->features & NETIF_F_HIGHDMA)) {
-		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 (PageHighMem(skb_frag_page(frag)))
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 18:06 ` [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible Matteo Croce
@ 2021-04-09 18:54   ` Jakub Kicinski
  2021-04-09 20:44     ` Matteo Croce
  2021-04-09 21:21   ` kernel test robot
  2021-04-10  0:27   ` kernel test robot
  2 siblings, 1 reply; 10+ messages in thread
From: Jakub Kicinski @ 2021-04-09 18:54 UTC (permalink / raw)
  To: Matteo Croce; +Cc: netdev, linux-kernel, David S. Miller, Julia Lawall

On Fri,  9 Apr 2021 20:06:04 +0200 Matteo Croce wrote:
> From: Matteo Croce <mcroce@microsoft.com>
> 
> 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:

Bunch of set but not used warnings here. Please make sure the code
builds cleanly allmodconfig, W=1 C=1 before posting.

What pops to mind (although quite nit picky) is the question if the
assembly changes much between driver which used to cache nr_frags and
now always going skb_shinfo(skb)->nr_frags? It's a relatively common
pattern.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 18:54   ` Jakub Kicinski
@ 2021-04-09 20:44     ` Matteo Croce
  2021-04-09 21:28       ` Jakub Kicinski
  0 siblings, 1 reply; 10+ messages in thread
From: Matteo Croce @ 2021-04-09 20:44 UTC (permalink / raw)
  To: Jakub Kicinski; +Cc: netdev, linux-kernel, David S. Miller, Julia Lawall

On Fri, Apr 9, 2021 at 8:54 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Fri,  9 Apr 2021 20:06:04 +0200 Matteo Croce wrote:
> > From: Matteo Croce <mcroce@microsoft.com>
> >
> > 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:
>
> Bunch of set but not used warnings here. Please make sure the code
> builds cleanly allmodconfig, W=1 C=1 before posting.
>

Will do.

> What pops to mind (although quite nit picky) is the question if the
> assembly changes much between driver which used to cache nr_frags and
> now always going skb_shinfo(skb)->nr_frags? It's a relatively common
> pattern.

Since skb_shinfo() is a macro and skb_end_pointer() a static inline,
it should be the same, but I was curious to check so, this is a diff
between the following snippet before and afer the macro:

int frags = skb_shinfo(skb)->nr_frags;
int i;
for (i = 0; i < frags; i++)
    kfree(skb->frags[i]);

 1 file changed, 8 insertions(+), 7 deletions(-)

--- ins1.s 2021-04-09 22:35:59.384523865 +0200
+++ ins2.s 2021-04-09 22:36:08.132594737 +0200
@@ -1,26 +1,27 @@
 iter:
         movsx   rax, DWORD PTR [rdi+16]
         mov     rdx, QWORD PTR [rdi+8]
         mov     eax, DWORD PTR [rdx+rax]
         test    eax, eax
         jle     .L6
         push    rbp
-        sub     eax, 1
+        mov     rbp, rdi
         push    rbx
-        lea     rbp, [rdi+32+rax*8]
-        lea     rbx, [rdi+24]
+        xor     ebx, ebx
         sub     rsp, 8
 .L3:
-        mov     rdi, QWORD PTR [rbx]
-        add     rbx, 8
+        mov     rdi, QWORD PTR [rbp+24+rbx*8]
+        add     rbx, 1
         call    kfree
-        cmp     rbx, rbp
-        jne     .L3
+        movsx   rax, DWORD PTR [rbp+16]
+        mov     rdx, QWORD PTR [rbp+8]
+        cmp     DWORD PTR [rdx+rax], ebx
+        jg      .L3
         add     rsp, 8
         xor     eax, eax
         pop     rbx
         pop     rbp
         ret
 .L6:
         xor     eax, eax
         ret

-- 
per aspera ad upstream

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 18:06 ` [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible Matteo Croce
  2021-04-09 18:54   ` Jakub Kicinski
@ 2021-04-09 21:21   ` kernel test robot
  2021-04-10  0:27   ` kernel test robot
  2 siblings, 0 replies; 10+ messages in thread
From: kernel test robot @ 2021-04-09 21:21 UTC (permalink / raw)
  To: Matteo Croce, netdev
  Cc: kbuild-all, linux-kernel, Jakub Kicinski, Julia Lawall

[-- Attachment #1: Type: text/plain, Size: 8641 bytes --]

Hi Matteo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Matteo-Croce/introduce-skb_for_each_frag/20210410-020828
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 4438669eb703d1a7416c2b19a8a15b0400b36738
config: xtensa-allyesconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/9a46b324d3f1ca289db31c0011a6bbfd5ae06918
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matteo-Croce/introduce-skb_for_each_frag/20210410-020828
        git checkout 9a46b324d3f1ca289db31c0011a6bbfd5ae06918
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c: In function 'netxen_map_tx_skb':
>> drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c:1975:9: warning: variable 'nr_frags' set but not used [-Wunused-but-set-variable]
    1975 |  int i, nr_frags;
         |         ^~~~~~~~
--
   drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c: In function 'qlcnic_map_tx_skb':
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c:584:9: warning: variable 'nr_frags' set but not used [-Wunused-but-set-variable]
     584 |  int i, nr_frags;
         |         ^~~~~~~~


vim +/nr_frags +1975 drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c

cd1f8160e015cd drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2008-07-21  1968  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1969  static int
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1970  netxen_map_tx_skb(struct pci_dev *pdev,
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1971  		struct sk_buff *skb, struct netxen_cmd_buffer *pbuf)
6f70340698333f drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-01-14  1972  {
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1973  	struct netxen_skb_frag *nf;
d7840976e39156 drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Matthew Wilcox (Oracle  2019-07-22  1974) 	skb_frag_t *frag;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23 @1975  	int i, nr_frags;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1976  	dma_addr_t map;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1977  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1978  	nr_frags = skb_shinfo(skb)->nr_frags;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1979  	nf = &pbuf->frag_array[0];
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1980  
297af515d75f5c drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Christophe JAILLET      2021-01-13  1981  	map = dma_map_single(&pdev->dev, skb->data, skb_headlen(skb),
297af515d75f5c drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Christophe JAILLET      2021-01-13  1982  			     DMA_TO_DEVICE);
297af515d75f5c drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Christophe JAILLET      2021-01-13  1983  	if (dma_mapping_error(&pdev->dev, map))
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1984  		goto out_err;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1985  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1986  	nf->dma = map;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1987  	nf->length = skb_headlen(skb);
6f70340698333f drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-01-14  1988  
9a46b324d3f1ca drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Matteo Croce            2021-04-09  1989  	skb_for_each_frag(skb, i) {
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1990  		frag = &skb_shinfo(skb)->frags[i];
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1991  		nf = &pbuf->frag_array[i+1];
6f70340698333f drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-01-14  1992  
9e903e085262ff drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Eric Dumazet            2011-10-18  1993  		map = skb_frag_dma_map(&pdev->dev, frag, 0, skb_frag_size(frag),
5d6bcdfe38ce88 drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Ian Campbell            2011-10-06  1994  				       DMA_TO_DEVICE);
5d6bcdfe38ce88 drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Ian Campbell            2011-10-06  1995  		if (dma_mapping_error(&pdev->dev, map))
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1996  			goto unwind;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1997  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  1998  		nf->dma = map;
9e903e085262ff drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Eric Dumazet            2011-10-18  1999  		nf->length = skb_frag_size(frag);
6f70340698333f drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-01-14  2000  	}
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2001  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2002  	return 0;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2003  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2004  unwind:
cf503e8f458cec drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-09-03  2005  	while (--i >= 0) {
cf503e8f458cec drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-09-03  2006  		nf = &pbuf->frag_array[i+1];
297af515d75f5c drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Christophe JAILLET      2021-01-13  2007  		dma_unmap_page(&pdev->dev, nf->dma, nf->length, DMA_TO_DEVICE);
a05948f296ce10 drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Eric Dumazet            2013-01-22  2008  		nf->dma = 0ULL;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2009  	}
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2010  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2011  	nf = &pbuf->frag_array[0];
297af515d75f5c drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Christophe JAILLET      2021-01-13  2012  	dma_unmap_single(&pdev->dev, nf->dma, skb_headlen(skb), DMA_TO_DEVICE);
a05948f296ce10 drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c Eric Dumazet            2013-01-22  2013  	nf->dma = 0ULL;
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2014  
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2015  out_err:
ce644ed4db3ee1 drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-08-23  2016  	return -ENOMEM;
6f70340698333f drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-01-14  2017  }
6f70340698333f drivers/net/netxen/netxen_nic_main.c                 Dhananjay Phadke        2009-01-14  2018  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 67334 bytes --]

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 20:44     ` Matteo Croce
@ 2021-04-09 21:28       ` Jakub Kicinski
  2021-04-10  0:53         ` Matteo Croce
  0 siblings, 1 reply; 10+ messages in thread
From: Jakub Kicinski @ 2021-04-09 21:28 UTC (permalink / raw)
  To: Matteo Croce; +Cc: netdev, linux-kernel, David S. Miller, Julia Lawall

On Fri, 9 Apr 2021 22:44:50 +0200 Matteo Croce wrote:
> > What pops to mind (although quite nit picky) is the question if the
> > assembly changes much between driver which used to cache nr_frags and
> > now always going skb_shinfo(skb)->nr_frags? It's a relatively common
> > pattern.  
> 
> Since skb_shinfo() is a macro and skb_end_pointer() a static inline,
> it should be the same, but I was curious to check so, this is a diff
> between the following snippet before and afer the macro:
> 
> int frags = skb_shinfo(skb)->nr_frags;
> int i;
> for (i = 0; i < frags; i++)
>     kfree(skb->frags[i]);
> 
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> --- ins1.s 2021-04-09 22:35:59.384523865 +0200
> +++ ins2.s 2021-04-09 22:36:08.132594737 +0200
> @@ -1,26 +1,27 @@
>  iter:
>          movsx   rax, DWORD PTR [rdi+16]
>          mov     rdx, QWORD PTR [rdi+8]
>          mov     eax, DWORD PTR [rdx+rax]
>          test    eax, eax
>          jle     .L6
>          push    rbp
> -        sub     eax, 1
> +        mov     rbp, rdi
>          push    rbx
> -        lea     rbp, [rdi+32+rax*8]
> -        lea     rbx, [rdi+24]
> +        xor     ebx, ebx
>          sub     rsp, 8
>  .L3:
> -        mov     rdi, QWORD PTR [rbx]
> -        add     rbx, 8
> +        mov     rdi, QWORD PTR [rbp+24+rbx*8]
> +        add     rbx, 1
>          call    kfree
> -        cmp     rbx, rbp
> -        jne     .L3
> +        movsx   rax, DWORD PTR [rbp+16]
> +        mov     rdx, QWORD PTR [rbp+8]
> +        cmp     DWORD PTR [rdx+rax], ebx
> +        jg      .L3
>          add     rsp, 8
>          xor     eax, eax
>          pop     rbx
>          pop     rbp
>          ret
>  .L6:
>          xor     eax, eax
>      for (i = 0; i < frags; i++)    ret
> 

So looks like before compiler generated:

	end = &frags[nfrags]
	for (ptr = &frag[0]; ptr < end; ptr++)

and now it has to use the actual value of i, read nfrags in the loop
each time and compare it to i.

That makes sense, since it can't prove kfree() doesn't change nr_frags.

IDK if we care, but at least commit message should mention this.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 18:06 ` [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible Matteo Croce
  2021-04-09 18:54   ` Jakub Kicinski
  2021-04-09 21:21   ` kernel test robot
@ 2021-04-10  0:27   ` kernel test robot
  2 siblings, 0 replies; 10+ messages in thread
From: kernel test robot @ 2021-04-10  0:27 UTC (permalink / raw)
  To: Matteo Croce, netdev
  Cc: kbuild-all, linux-kernel, Jakub Kicinski, Julia Lawall

[-- Attachment #1: Type: text/plain, Size: 6604 bytes --]

Hi Matteo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Matteo-Croce/introduce-skb_for_each_frag/20210410-020828
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 4438669eb703d1a7416c2b19a8a15b0400b36738
config: um-allmodconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/9a46b324d3f1ca289db31c0011a6bbfd5ae06918
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matteo-Croce/introduce-skb_for_each_frag/20210410-020828
        git checkout 9a46b324d3f1ca289db31c0011a6bbfd5ae06918
        # save the attached .config to linux build tree
        make W=1 ARCH=um 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   cc1: warning: arch/um/include/uapi: No such file or directory [-Wmissing-include-dirs]
   arch/um/drivers/vector_kern.c: In function 'get_bpf_flash':
   arch/um/drivers/vector_kern.c:145:18: warning: ordered comparison of pointer with integer zero [-Wextra]
     145 |    return (allow > 0);
         |                  ^
   arch/um/drivers/vector_kern.c: In function 'prep_skb':
>> arch/um/drivers/vector_kern.c:627:11: warning: variable 'nr_frags' set but not used [-Wunused-but-set-variable]
     627 |  int err, nr_frags, frag;
         |           ^~~~~~~~
   arch/um/drivers/vector_kern.c: In function 'vector_parse':
   arch/um/drivers/vector_kern.c:719:9: warning: variable 'len' set but not used [-Wunused-but-set-variable]
     719 |  int n, len, err;
         |         ^~~


vim +/nr_frags +627 arch/um/drivers/vector_kern.c

49da7e64f33e80 Anton Ivanov 2017-11-20  609  
49da7e64f33e80 Anton Ivanov 2017-11-20  610  /*
49da7e64f33e80 Anton Ivanov 2017-11-20  611   * We do not use the RX queue as a proper wraparound queue for now
49da7e64f33e80 Anton Ivanov 2017-11-20  612   * This is not necessary because the consumption via netif_rx()
49da7e64f33e80 Anton Ivanov 2017-11-20  613   * happens in-line. While we can try using the return code of
49da7e64f33e80 Anton Ivanov 2017-11-20  614   * netif_rx() for flow control there are no drivers doing this today.
49da7e64f33e80 Anton Ivanov 2017-11-20  615   * For this RX specific use we ignore the tail/head locks and
49da7e64f33e80 Anton Ivanov 2017-11-20  616   * just read into a prepared queue filled with skbuffs.
49da7e64f33e80 Anton Ivanov 2017-11-20  617   */
49da7e64f33e80 Anton Ivanov 2017-11-20  618  
49da7e64f33e80 Anton Ivanov 2017-11-20  619  static struct sk_buff *prep_skb(
49da7e64f33e80 Anton Ivanov 2017-11-20  620  	struct vector_private *vp,
49da7e64f33e80 Anton Ivanov 2017-11-20  621  	struct user_msghdr *msg)
49da7e64f33e80 Anton Ivanov 2017-11-20  622  {
49da7e64f33e80 Anton Ivanov 2017-11-20  623  	int linear = vp->max_packet + vp->headroom + SAFETY_MARGIN;
49da7e64f33e80 Anton Ivanov 2017-11-20  624  	struct sk_buff *result;
49da7e64f33e80 Anton Ivanov 2017-11-20  625  	int iov_index = 0, len;
49da7e64f33e80 Anton Ivanov 2017-11-20  626  	struct iovec *iov = msg->msg_iov;
49da7e64f33e80 Anton Ivanov 2017-11-20 @627  	int err, nr_frags, frag;
49da7e64f33e80 Anton Ivanov 2017-11-20  628  	skb_frag_t *skb_frag;
49da7e64f33e80 Anton Ivanov 2017-11-20  629  
49da7e64f33e80 Anton Ivanov 2017-11-20  630  	if (vp->req_size <= linear)
49da7e64f33e80 Anton Ivanov 2017-11-20  631  		len = linear;
49da7e64f33e80 Anton Ivanov 2017-11-20  632  	else
49da7e64f33e80 Anton Ivanov 2017-11-20  633  		len = vp->req_size;
49da7e64f33e80 Anton Ivanov 2017-11-20  634  	result = alloc_skb_with_frags(
49da7e64f33e80 Anton Ivanov 2017-11-20  635  		linear,
49da7e64f33e80 Anton Ivanov 2017-11-20  636  		len - vp->max_packet,
49da7e64f33e80 Anton Ivanov 2017-11-20  637  		3,
49da7e64f33e80 Anton Ivanov 2017-11-20  638  		&err,
49da7e64f33e80 Anton Ivanov 2017-11-20  639  		GFP_ATOMIC
49da7e64f33e80 Anton Ivanov 2017-11-20  640  	);
49da7e64f33e80 Anton Ivanov 2017-11-20  641  	if (vp->header_size > 0)
49da7e64f33e80 Anton Ivanov 2017-11-20  642  		iov_index++;
49da7e64f33e80 Anton Ivanov 2017-11-20  643  	if (result == NULL) {
49da7e64f33e80 Anton Ivanov 2017-11-20  644  		iov[iov_index].iov_base = NULL;
49da7e64f33e80 Anton Ivanov 2017-11-20  645  		iov[iov_index].iov_len = 0;
49da7e64f33e80 Anton Ivanov 2017-11-20  646  		goto done;
49da7e64f33e80 Anton Ivanov 2017-11-20  647  	}
49da7e64f33e80 Anton Ivanov 2017-11-20  648  	skb_reserve(result, vp->headroom);
49da7e64f33e80 Anton Ivanov 2017-11-20  649  	result->dev = vp->dev;
49da7e64f33e80 Anton Ivanov 2017-11-20  650  	skb_put(result, vp->max_packet);
49da7e64f33e80 Anton Ivanov 2017-11-20  651  	result->data_len = len - vp->max_packet;
49da7e64f33e80 Anton Ivanov 2017-11-20  652  	result->len += len - vp->max_packet;
49da7e64f33e80 Anton Ivanov 2017-11-20  653  	skb_reset_mac_header(result);
49da7e64f33e80 Anton Ivanov 2017-11-20  654  	result->ip_summed = CHECKSUM_NONE;
49da7e64f33e80 Anton Ivanov 2017-11-20  655  	iov[iov_index].iov_base = result->data;
49da7e64f33e80 Anton Ivanov 2017-11-20  656  	iov[iov_index].iov_len = vp->max_packet;
49da7e64f33e80 Anton Ivanov 2017-11-20  657  	iov_index++;
49da7e64f33e80 Anton Ivanov 2017-11-20  658  
49da7e64f33e80 Anton Ivanov 2017-11-20  659  	nr_frags = skb_shinfo(result)->nr_frags;
9a46b324d3f1ca Matteo Croce 2021-04-09  660  	skb_for_each_frag(result, frag) {
49da7e64f33e80 Anton Ivanov 2017-11-20  661  		skb_frag = &skb_shinfo(result)->frags[frag];
49da7e64f33e80 Anton Ivanov 2017-11-20  662  		iov[iov_index].iov_base = skb_frag_address_safe(skb_frag);
49da7e64f33e80 Anton Ivanov 2017-11-20  663  		if (iov[iov_index].iov_base != NULL)
49da7e64f33e80 Anton Ivanov 2017-11-20  664  			iov[iov_index].iov_len = skb_frag_size(skb_frag);
49da7e64f33e80 Anton Ivanov 2017-11-20  665  		else
49da7e64f33e80 Anton Ivanov 2017-11-20  666  			iov[iov_index].iov_len = 0;
49da7e64f33e80 Anton Ivanov 2017-11-20  667  		iov_index++;
49da7e64f33e80 Anton Ivanov 2017-11-20  668  	}
49da7e64f33e80 Anton Ivanov 2017-11-20  669  done:
49da7e64f33e80 Anton Ivanov 2017-11-20  670  	msg->msg_iovlen = iov_index;
49da7e64f33e80 Anton Ivanov 2017-11-20  671  	return result;
49da7e64f33e80 Anton Ivanov 2017-11-20  672  }
49da7e64f33e80 Anton Ivanov 2017-11-20  673  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 24381 bytes --]

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible
  2021-04-09 21:28       ` Jakub Kicinski
@ 2021-04-10  0:53         ` Matteo Croce
  0 siblings, 0 replies; 10+ messages in thread
From: Matteo Croce @ 2021-04-10  0:53 UTC (permalink / raw)
  To: Jakub Kicinski; +Cc: netdev, linux-kernel, David S. Miller, Julia Lawall

On Fri, Apr 9, 2021 at 11:28 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Fri, 9 Apr 2021 22:44:50 +0200 Matteo Croce wrote:
> > > What pops to mind (although quite nit picky) is the question if the
> > > assembly changes much between driver which used to cache nr_frags and
> > > now always going skb_shinfo(skb)->nr_frags? It's a relatively common
> > > pattern.
> >
> > Since skb_shinfo() is a macro and skb_end_pointer() a static inline,
> > it should be the same, but I was curious to check so, this is a diff
> > between the following snippet before and afer the macro:
> >
> > int frags = skb_shinfo(skb)->nr_frags;
> > int i;
> > for (i = 0; i < frags; i++)
> >     kfree(skb->frags[i]);
> >
> >  1 file changed, 8 insertions(+), 7 deletions(-)
> >
> > --- ins1.s 2021-04-09 22:35:59.384523865 +0200
> > +++ ins2.s 2021-04-09 22:36:08.132594737 +0200
> > @@ -1,26 +1,27 @@
> >  iter:
> >          movsx   rax, DWORD PTR [rdi+16]
> >          mov     rdx, QWORD PTR [rdi+8]
> >          mov     eax, DWORD PTR [rdx+rax]
> >          test    eax, eax
> >          jle     .L6
> >          push    rbp
> > -        sub     eax, 1
> > +        mov     rbp, rdi
> >          push    rbx
> > -        lea     rbp, [rdi+32+rax*8]
> > -        lea     rbx, [rdi+24]
> > +        xor     ebx, ebx
> >          sub     rsp, 8
> >  .L3:
> > -        mov     rdi, QWORD PTR [rbx]
> > -        add     rbx, 8
> > +        mov     rdi, QWORD PTR [rbp+24+rbx*8]
> > +        add     rbx, 1
> >          call    kfree
> > -        cmp     rbx, rbp
> > -        jne     .L3
> > +        movsx   rax, DWORD PTR [rbp+16]
> > +        mov     rdx, QWORD PTR [rbp+8]
> > +        cmp     DWORD PTR [rdx+rax], ebx
> > +        jg      .L3
> >          add     rsp, 8
> >          xor     eax, eax
> >          pop     rbx
> >          pop     rbp
> >          ret
> >  .L6:
> >          xor     eax, eax
> >      for (i = 0; i < frags; i++)    ret
> >
>
> So looks like before compiler generated:
>
>         end = &frags[nfrags]
>         for (ptr = &frag[0]; ptr < end; ptr++)
>
> and now it has to use the actual value of i, read nfrags in the loop
> each time and compare it to i.
>
> That makes sense, since it can't prove kfree() doesn't change nr_frags.
>
> IDK if we care, but at least commit message should mention this.

Anyway, the chunks using a local nr_frags are too few and not worth it.
I think you're right and that's better to use the cached value, I see
the instructions here being ligther.
Drop the series, I will make a new one which only acts where
skb_shinfo(skb) is accessed.

Thanks,
-- 
per aspera ad upstream

^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2021-04-10  0:54 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-09 18:06 [PATCH net-next 0/3] introduce skb_for_each_frag() Matteo Croce
2021-04-09 18:06 ` [PATCH net-next 1/3] skbuff: add helper to walk over the fraglist Matteo Croce
2021-04-09 18:06 ` [PATCH net-next 2/3] net: use skb_for_each_frag() helper where possible Matteo Croce
2021-04-09 18:54   ` Jakub Kicinski
2021-04-09 20:44     ` Matteo Croce
2021-04-09 21:28       ` Jakub Kicinski
2021-04-10  0:53         ` Matteo Croce
2021-04-09 21:21   ` kernel test robot
2021-04-10  0:27   ` kernel test robot
2021-04-09 18:06 ` [PATCH net-next 3/3] net: use skb_for_each_frag() in illegal_highdma() Matteo Croce

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