Hi, On 12.02.2022 00:38, Sebastian Andrzej Siewior wrote: > Dave suggested a while ago (eleven years by now) "Let's make netif_rx() > work in all contexts and get rid of netif_rx_ni()". Eric agreed and > pointed out that modern devices should use netif_receive_skb() to avoid > the overhead. > In the meantime someone added another variant, netif_rx_any_context(), > which behaves as suggested. > > netif_rx() must be invoked with disabled bottom halves to ensure that > pending softirqs, which were raised within the function, are handled. > netif_rx_ni() can be invoked only from process context (bottom halves > must be enabled) because the function handles pending softirqs without > checking if bottom halves were disabled or not. > netif_rx_any_context() invokes on the former functions by checking > in_interrupts(). > > netif_rx() could be taught to handle both cases (disabled and enabled > bottom halves) by simply disabling bottom halves while invoking > netif_rx_internal(). The local_bh_enable() invocation will then invoke > pending softirqs only if the BH-disable counter drops to zero. > > Eric is concerned about the overhead of BH-disable+enable especially in > regard to the loopback driver. As critical as this driver is, it will > receive a shortcut to avoid the additional overhead which is not needed. > > Add a local_bh_disable() section in netif_rx() to ensure softirqs are > handled if needed. > Provide __netif_rx() which does not disable BH and has a lockdep assert > to ensure that interrupts are disabled. Use this shortcut in the > loopback driver and in drivers/net/*.c. > Make netif_rx_ni() and netif_rx_any_context() invoke netif_rx() so they > can be removed once they are no more users left. > > Link: https://lkml.kernel.org/r/20100415.020246.218622820.davem@xxxxxxxxxxxxx > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> > Reviewed-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> This patch landed in linux-next 20220215 as commit baebdf48c360 ("net: dev: Makes sure netif_rx() can be invoked in any context."). I found that it triggers the following warning on my test systems with USB CDC ethernet gadget: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 876 at kernel/softirq.c:308 __local_bh_disable_ip+0xbc/0xc0 Modules linked in: hci_uart btbcm btintel brcmfmac bluetooth s5p_mfc s5p_csis s5p_fimc s5p_jpeg cfg80211 v4l2_mem2mem videobuf2_dma_contig videobuf2_memops exynos4_is_common videobuf2_v4l2 v4l2_fwnode videobuf2_common v4l2_async videodev ecdh_generic ecc brcmutil mc CPU: 0 PID: 876 Comm: ip Not tainted 5.17.0-rc3-01145-gbaebdf48c360 #11325 Hardware name: Samsung Exynos (Flattened Device Tree) unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x58/0x70 dump_stack_lvl from __warn+0x238/0x23c __warn from warn_slowpath_fmt+0xac/0xb4 warn_slowpath_fmt from __local_bh_disable_ip+0xbc/0xc0 __local_bh_disable_ip from netif_rx+0x1c/0x28c netif_rx from rx_complete+0x12c/0x224 rx_complete from dwc2_hsotg_complete_request+0x94/0x208 dwc2_hsotg_complete_request from dwc2_hsotg_epint+0x9ac/0x1224 dwc2_hsotg_epint from dwc2_hsotg_irq+0x264/0x1020 dwc2_hsotg_irq from __handle_irq_event_percpu+0x74/0x3ac __handle_irq_event_percpu from handle_irq_event_percpu+0xc/0x38 handle_irq_event_percpu from handle_irq_event+0x38/0x5c handle_irq_event from handle_fasteoi_irq+0xc4/0x180 handle_fasteoi_irq from generic_handle_domain_irq+0x44/0x88 generic_handle_domain_irq from gic_handle_irq+0x88/0xac gic_handle_irq from generic_handle_arch_irq+0x58/0x78 generic_handle_arch_irq from __irq_svc+0x54/0x88 Exception stack(0xc3fb58e0 to 0xc3fb5928) 58e0: 00000000 c0f33a98 00000001 00000cbb 60000013 c2dc8730 c2dc875c 00000cc0 5900: c2d2cc00 00000001 00000000 00000000 00000001 c3fb5930 c0b7dbc4 c0b890d4 5920: 20000013 ffffffff __irq_svc from _raw_spin_unlock_irqrestore+0x2c/0x60 _raw_spin_unlock_irqrestore from rx_fill+0x6c/0xa0 rx_fill from eth_open+0x60/0x74 eth_open from __dev_open+0xf0/0x174 __dev_open from __dev_change_flags+0x16c/0x1b8 __dev_change_flags from dev_change_flags+0x14/0x44 dev_change_flags from do_setlink+0x33c/0xa3c do_setlink from __rtnl_newlink+0x524/0x80c __rtnl_newlink from rtnl_newlink+0x44/0x60 rtnl_newlink from rtnetlink_rcv_msg+0x14c/0x4ec rtnetlink_rcv_msg from netlink_rcv_skb+0xdc/0x110 netlink_rcv_skb from netlink_unicast+0x1ac/0x244 netlink_unicast from netlink_sendmsg+0x328/0x448 netlink_sendmsg from ____sys_sendmsg+0x1c4/0x220 ____sys_sendmsg from ___sys_sendmsg+0x68/0x94 ___sys_sendmsg from __sys_sendmsg+0x4c/0x88 __sys_sendmsg from ret_fast_syscall+0x0/0x1c Exception stack(0xc3fb5fa8 to 0xc3fb5ff0) 5fa0: beacb6dc beac3624 00000003 beac3630 00000000 00000000 5fc0: beacb6dc beac3624 00000000 00000128 0054e304 386d3fd2 0054e000 beac3630 5fe0: 0000006c beac35e0 00517f80 b6ea2ab8 irq event stamp: 3260 hardirqs last enabled at (3259): [<c0b89104>] _raw_spin_unlock_irqrestore+0x5c/0x60 hardirqs last disabled at (3260): [<c0100aec>] __irq_svc+0x4c/0x88 softirqs last enabled at (3250): [<c0982a90>] __dev_change_flags+0x80/0x1b8 softirqs last disabled at (3248): [<c0982690>] dev_set_rx_mode+0x0/0x40 ---[ end trace 0000000000000000 ]--- ------------[ cut here ]------------ WARNING: CPU: 0 PID: 876 at kernel/softirq.c:362 __local_bh_enable_ip+0x200/0x204 Modules linked in: hci_uart btbcm btintel brcmfmac bluetooth s5p_mfc s5p_csis s5p_fimc s5p_jpeg cfg80211 v4l2_mem2mem videobuf2_dma_contig videobuf2_memops exynos4_is_common videobuf2_v4l2 v4l2_fwnode videobuf2_common v4l2_async videodev ecdh_generic ecc brcmutil mc CPU: 0 PID: 876 Comm: ip Tainted: G W 5.17.0-rc3-01145-gbaebdf48c360 #11325 Hardware name: Samsung Exynos (Flattened Device Tree) unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x58/0x70 dump_stack_lvl from __warn+0x238/0x23c __warn from warn_slowpath_fmt+0xac/0xb4 warn_slowpath_fmt from __local_bh_enable_ip+0x200/0x204 __local_bh_enable_ip from netif_rx+0x9c/0x28c netif_rx from rx_complete+0x12c/0x224 rx_complete from dwc2_hsotg_complete_request+0x94/0x208 dwc2_hsotg_complete_request from dwc2_hsotg_epint+0x9ac/0x1224 dwc2_hsotg_epint from dwc2_hsotg_irq+0x264/0x1020 dwc2_hsotg_irq from __handle_irq_event_percpu+0x74/0x3ac __handle_irq_event_percpu from handle_irq_event_percpu+0xc/0x38 handle_irq_event_percpu from handle_irq_event+0x38/0x5c handle_irq_event from handle_fasteoi_irq+0xc4/0x180 handle_fasteoi_irq from generic_handle_domain_irq+0x44/0x88 generic_handle_domain_irq from gic_handle_irq+0x88/0xac gic_handle_irq from generic_handle_arch_irq+0x58/0x78 generic_handle_arch_irq from __irq_svc+0x54/0x88 Exception stack(0xc3fb58e0 to 0xc3fb5928) 58e0: 00000000 c0f33a98 00000001 00000cbb 60000013 c2dc8730 c2dc875c 00000cc0 5900: c2d2cc00 00000001 00000000 00000000 00000001 c3fb5930 c0b7dbc4 c0b890d4 5920: 20000013 ffffffff __irq_svc from _raw_spin_unlock_irqrestore+0x2c/0x60 _raw_spin_unlock_irqrestore from rx_fill+0x6c/0xa0 rx_fill from eth_open+0x60/0x74 eth_open from __dev_open+0xf0/0x174 __dev_open from __dev_change_flags+0x16c/0x1b8 __dev_change_flags from dev_change_flags+0x14/0x44 dev_change_flags from do_setlink+0x33c/0xa3c do_setlink from __rtnl_newlink+0x524/0x80c __rtnl_newlink from rtnl_newlink+0x44/0x60 rtnl_newlink from rtnetlink_rcv_msg+0x14c/0x4ec rtnetlink_rcv_msg from netlink_rcv_skb+0xdc/0x110 netlink_rcv_skb from netlink_unicast+0x1ac/0x244 netlink_unicast from netlink_sendmsg+0x328/0x448 netlink_sendmsg from ____sys_sendmsg+0x1c4/0x220 ____sys_sendmsg from ___sys_sendmsg+0x68/0x94 ___sys_sendmsg from __sys_sendmsg+0x4c/0x88 __sys_sendmsg from ret_fast_syscall+0x0/0x1c Exception stack(0xc3fb5fa8 to 0xc3fb5ff0) 5fa0: beacb6dc beac3624 00000003 beac3630 00000000 00000000 5fc0: beacb6dc beac3624 00000000 00000128 0054e304 386d3fd2 0054e000 beac3630 5fe0: 0000006c beac35e0 00517f80 b6ea2ab8 irq event stamp: 3261 hardirqs last enabled at (3259): [<c0b89104>] _raw_spin_unlock_irqrestore+0x5c/0x60 hardirqs last disabled at (3260): [<c0100aec>] __irq_svc+0x4c/0x88 softirqs last enabled at (3250): [<c0982a90>] __dev_change_flags+0x80/0x1b8 softirqs last disabled at (3261): [<c097b808>] netif_rx+0x0/0x28c ---[ end trace 0000000000000000 ]--- The above log comes from Samsung Exynos4210-based Trats board (ARM32 bit), but similar are triggered on other boards too. > --- > drivers/net/amt.c | 4 +-- > drivers/net/geneve.c | 4 +-- > drivers/net/gtp.c | 2 +- > drivers/net/loopback.c | 4 +-- > drivers/net/macsec.c | 6 ++-- > drivers/net/macvlan.c | 4 +-- > drivers/net/mhi_net.c | 2 +- > drivers/net/ntb_netdev.c | 2 +- > drivers/net/rionet.c | 2 +- > drivers/net/sb1000.c | 2 +- > drivers/net/veth.c | 2 +- > drivers/net/vrf.c | 2 +- > drivers/net/vxlan.c | 2 +- > include/linux/netdevice.h | 14 ++++++-- > include/trace/events/net.h | 14 -------- > net/core/dev.c | 67 +++++++++++++++++--------------------- > 16 files changed, 60 insertions(+), 73 deletions(-) > > diff --git a/drivers/net/amt.c b/drivers/net/amt.c > index f1a36d7e2151c..10455c9b9da0e 100644 > --- a/drivers/net/amt.c > +++ b/drivers/net/amt.c > @@ -2373,7 +2373,7 @@ static bool amt_membership_query_handler(struct amt_dev *amt, > skb->pkt_type = PACKET_MULTICAST; > skb->ip_summed = CHECKSUM_NONE; > len = skb->len; > - if (netif_rx(skb) == NET_RX_SUCCESS) { > + if (__netif_rx(skb) == NET_RX_SUCCESS) { > amt_update_gw_status(amt, AMT_STATUS_RECEIVED_QUERY, true); > dev_sw_netstats_rx_add(amt->dev, len); > } else { > @@ -2470,7 +2470,7 @@ static bool amt_update_handler(struct amt_dev *amt, struct sk_buff *skb) > skb->pkt_type = PACKET_MULTICAST; > skb->ip_summed = CHECKSUM_NONE; > len = skb->len; > - if (netif_rx(skb) == NET_RX_SUCCESS) { > + if (__netif_rx(skb) == NET_RX_SUCCESS) { > amt_update_relay_status(tunnel, AMT_STATUS_RECEIVED_UPDATE, > true); > dev_sw_netstats_rx_add(amt->dev, len); > diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c > index c1fdd721a730d..a895ff756093a 100644 > --- a/drivers/net/geneve.c > +++ b/drivers/net/geneve.c > @@ -925,7 +925,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, > } > > skb->protocol = eth_type_trans(skb, geneve->dev); > - netif_rx(skb); > + __netif_rx(skb); > dst_release(&rt->dst); > return -EMSGSIZE; > } > @@ -1021,7 +1021,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, > } > > skb->protocol = eth_type_trans(skb, geneve->dev); > - netif_rx(skb); > + __netif_rx(skb); > dst_release(dst); > return -EMSGSIZE; > } > diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c > index 24e5c54d06c15..bf087171bcf04 100644 > --- a/drivers/net/gtp.c > +++ b/drivers/net/gtp.c > @@ -207,7 +207,7 @@ static int gtp_rx(struct pdp_ctx *pctx, struct sk_buff *skb, > > dev_sw_netstats_rx_add(pctx->dev, skb->len); > > - netif_rx(skb); > + __netif_rx(skb); > return 0; > > err: > diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c > index ed0edf5884ef8..d05f86fe78c95 100644 > --- a/drivers/net/loopback.c > +++ b/drivers/net/loopback.c > @@ -78,7 +78,7 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb, > > skb_orphan(skb); > > - /* Before queueing this packet to netif_rx(), > + /* Before queueing this packet to __netif_rx(), > * make sure dst is refcounted. > */ > skb_dst_force(skb); > @@ -86,7 +86,7 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb, > skb->protocol = eth_type_trans(skb, dev); > > len = skb->len; > - if (likely(netif_rx(skb) == NET_RX_SUCCESS)) > + if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) > dev_lstats_add(dev, len); > > return NETDEV_TX_OK; > diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c > index 3d08743317634..832f09ac075e7 100644 > --- a/drivers/net/macsec.c > +++ b/drivers/net/macsec.c > @@ -1033,7 +1033,7 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb) > else > nskb->pkt_type = PACKET_MULTICAST; > > - netif_rx(nskb); > + __netif_rx(nskb); > } > continue; > } > @@ -1056,7 +1056,7 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb) > > nskb->dev = ndev; > > - if (netif_rx(nskb) == NET_RX_SUCCESS) { > + if (__netif_rx(nskb) == NET_RX_SUCCESS) { > u64_stats_update_begin(&secy_stats->syncp); > secy_stats->stats.InPktsUntagged++; > u64_stats_update_end(&secy_stats->syncp); > @@ -1288,7 +1288,7 @@ static rx_handler_result_t macsec_handle_frame(struct sk_buff **pskb) > > macsec_reset_skb(nskb, macsec->secy.netdev); > > - ret = netif_rx(nskb); > + ret = __netif_rx(nskb); > if (ret == NET_RX_SUCCESS) { > u64_stats_update_begin(&secy_stats->syncp); > secy_stats->stats.InPktsUnknownSCI++; > diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c > index 6ef5f77be4d0a..d87c06c317ede 100644 > --- a/drivers/net/macvlan.c > +++ b/drivers/net/macvlan.c > @@ -410,7 +410,7 @@ static void macvlan_forward_source_one(struct sk_buff *skb, > if (ether_addr_equal_64bits(eth_hdr(skb)->h_dest, dev->dev_addr)) > nskb->pkt_type = PACKET_HOST; > > - ret = netif_rx(nskb); > + ret = __netif_rx(nskb); > macvlan_count_rx(vlan, len, ret == NET_RX_SUCCESS, false); > } > > @@ -468,7 +468,7 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb) > /* forward to original port. */ > vlan = src; > ret = macvlan_broadcast_one(skb, vlan, eth, 0) ?: > - netif_rx(skb); > + __netif_rx(skb); > handle_res = RX_HANDLER_CONSUMED; > goto out; > } > diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c > index aaa628f859fd4..0b1b6f650104b 100644 > --- a/drivers/net/mhi_net.c > +++ b/drivers/net/mhi_net.c > @@ -225,7 +225,7 @@ static void mhi_net_dl_callback(struct mhi_device *mhi_dev, > u64_stats_inc(&mhi_netdev->stats.rx_packets); > u64_stats_add(&mhi_netdev->stats.rx_bytes, skb->len); > u64_stats_update_end(&mhi_netdev->stats.rx_syncp); > - netif_rx(skb); > + __netif_rx(skb); > } > > /* Refill if RX buffers queue becomes low */ > diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c > index 98ca6b18415e7..80bdc07f2cd33 100644 > --- a/drivers/net/ntb_netdev.c > +++ b/drivers/net/ntb_netdev.c > @@ -119,7 +119,7 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data, > skb->protocol = eth_type_trans(skb, ndev); > skb->ip_summed = CHECKSUM_NONE; > > - if (netif_rx(skb) == NET_RX_DROP) { > + if (__netif_rx(skb) == NET_RX_DROP) { > ndev->stats.rx_errors++; > ndev->stats.rx_dropped++; > } else { > diff --git a/drivers/net/rionet.c b/drivers/net/rionet.c > index 1a95f3beb784d..39e61e07e4894 100644 > --- a/drivers/net/rionet.c > +++ b/drivers/net/rionet.c > @@ -109,7 +109,7 @@ static int rionet_rx_clean(struct net_device *ndev) > skb_put(rnet->rx_skb[i], RIO_MAX_MSG_SIZE); > rnet->rx_skb[i]->protocol = > eth_type_trans(rnet->rx_skb[i], ndev); > - error = netif_rx(rnet->rx_skb[i]); > + error = __netif_rx(rnet->rx_skb[i]); > > if (error == NET_RX_DROP) { > ndev->stats.rx_dropped++; > diff --git a/drivers/net/sb1000.c b/drivers/net/sb1000.c > index 57a6d598467b2..c3f8020571add 100644 > --- a/drivers/net/sb1000.c > +++ b/drivers/net/sb1000.c > @@ -872,7 +872,7 @@ printk("cm0: IP identification: %02x%02x fragment offset: %02x%02x\n", buffer[3 > > /* datagram completed: send to upper level */ > skb_trim(skb, dlen); > - netif_rx(skb); > + __netif_rx(skb); > stats->rx_bytes+=dlen; > stats->rx_packets++; > lp->rx_skb[ns] = NULL; > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > index 354a963075c5f..6754fb8d9fabc 100644 > --- a/drivers/net/veth.c > +++ b/drivers/net/veth.c > @@ -286,7 +286,7 @@ static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb, > { > return __dev_forward_skb(dev, skb) ?: xdp ? > veth_xdp_rx(rq, skb) : > - netif_rx(skb); > + __netif_rx(skb); > } > > /* return true if the specified skb has chances of GRO aggregation > diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c > index e0b1ab99a359e..714cafcf6c6c8 100644 > --- a/drivers/net/vrf.c > +++ b/drivers/net/vrf.c > @@ -418,7 +418,7 @@ static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev, > > skb->protocol = eth_type_trans(skb, dev); > > - if (likely(netif_rx(skb) == NET_RX_SUCCESS)) > + if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) > vrf_rx_stats(dev, len); > else > this_cpu_inc(dev->dstats->rx_drps); > diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c > index 359d16780dbbc..d0dc90d3dac28 100644 > --- a/drivers/net/vxlan.c > +++ b/drivers/net/vxlan.c > @@ -2541,7 +2541,7 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan, > tx_stats->tx_bytes += len; > u64_stats_update_end(&tx_stats->syncp); > > - if (netif_rx(skb) == NET_RX_SUCCESS) { > + if (__netif_rx(skb) == NET_RX_SUCCESS) { > u64_stats_update_begin(&rx_stats->syncp); > rx_stats->rx_packets++; > rx_stats->rx_bytes += len; > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index e490b84732d16..c9e883104adb1 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -3669,8 +3669,18 @@ u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp, > void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog); > int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb); > int netif_rx(struct sk_buff *skb); > -int netif_rx_ni(struct sk_buff *skb); > -int netif_rx_any_context(struct sk_buff *skb); > +int __netif_rx(struct sk_buff *skb); > + > +static inline int netif_rx_ni(struct sk_buff *skb) > +{ > + return netif_rx(skb); > +} > + > +static inline int netif_rx_any_context(struct sk_buff *skb) > +{ > + return netif_rx(skb); > +} > + > int netif_receive_skb(struct sk_buff *skb); > int netif_receive_skb_core(struct sk_buff *skb); > void netif_receive_skb_list_internal(struct list_head *head); > diff --git a/include/trace/events/net.h b/include/trace/events/net.h > index 78c448c6ab4c5..032b431b987b6 100644 > --- a/include/trace/events/net.h > +++ b/include/trace/events/net.h > @@ -260,13 +260,6 @@ DEFINE_EVENT(net_dev_rx_verbose_template, netif_rx_entry, > TP_ARGS(skb) > ); > > -DEFINE_EVENT(net_dev_rx_verbose_template, netif_rx_ni_entry, > - > - TP_PROTO(const struct sk_buff *skb), > - > - TP_ARGS(skb) > -); > - > DECLARE_EVENT_CLASS(net_dev_rx_exit_template, > > TP_PROTO(int ret), > @@ -312,13 +305,6 @@ DEFINE_EVENT(net_dev_rx_exit_template, netif_rx_exit, > TP_ARGS(ret) > ); > > -DEFINE_EVENT(net_dev_rx_exit_template, netif_rx_ni_exit, > - > - TP_PROTO(int ret), > - > - TP_ARGS(ret) > -); > - > DEFINE_EVENT(net_dev_rx_exit_template, netif_receive_skb_list_exit, > > TP_PROTO(int ret), > diff --git a/net/core/dev.c b/net/core/dev.c > index 0d13340ed4054..7d90f565e540a 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -4815,66 +4815,57 @@ static int netif_rx_internal(struct sk_buff *skb) > return ret; > } > > +/** > + * __netif_rx - Slightly optimized version of netif_rx > + * @skb: buffer to post > + * > + * This behaves as netif_rx except that it does not disable bottom halves. > + * As a result this function may only be invoked from the interrupt context > + * (either hard or soft interrupt). > + */ > +int __netif_rx(struct sk_buff *skb) > +{ > + int ret; > + > + lockdep_assert_once(hardirq_count() | softirq_count()); > + > + trace_netif_rx_entry(skb); > + ret = netif_rx_internal(skb); > + trace_netif_rx_exit(ret); > + return ret; > +} > +EXPORT_SYMBOL(__netif_rx); > + > /** > * netif_rx - post buffer to the network code > * @skb: buffer to post > * > * This function receives a packet from a device driver and queues it for > - * the upper (protocol) levels to process. It always succeeds. The buffer > - * may be dropped during processing for congestion control or by the > - * protocol layers. > + * the upper (protocol) levels to process via the backlog NAPI device. It > + * always succeeds. The buffer may be dropped during processing for > + * congestion control or by the protocol layers. > + * The network buffer is passed via the backlog NAPI device. Modern NIC > + * driver should use NAPI and GRO. > + * This function can used from any context. > * > * return values: > * NET_RX_SUCCESS (no congestion) > * NET_RX_DROP (packet was dropped) > * > */ > - > int netif_rx(struct sk_buff *skb) > { > int ret; > > + local_bh_disable(); > trace_netif_rx_entry(skb); > - > ret = netif_rx_internal(skb); > trace_netif_rx_exit(ret); > - > + local_bh_enable(); > return ret; > } > EXPORT_SYMBOL(netif_rx); > > -int netif_rx_ni(struct sk_buff *skb) > -{ > - int err; > - > - trace_netif_rx_ni_entry(skb); > - > - preempt_disable(); > - err = netif_rx_internal(skb); > - if (local_softirq_pending()) > - do_softirq(); > - preempt_enable(); > - trace_netif_rx_ni_exit(err); > - > - return err; > -} > -EXPORT_SYMBOL(netif_rx_ni); > - > -int netif_rx_any_context(struct sk_buff *skb) > -{ > - /* > - * If invoked from contexts which do not invoke bottom half > - * processing either at return from interrupt or when softrqs are > - * reenabled, use netif_rx_ni() which invokes bottomhalf processing > - * directly. > - */ > - if (in_interrupt()) > - return netif_rx(skb); > - else > - return netif_rx_ni(skb); > -} > -EXPORT_SYMBOL(netif_rx_any_context); > - > static __latent_entropy void net_tx_action(struct softirq_action *h) > { > struct softnet_data *sd = this_cpu_ptr(&softnet_data); Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
