kernel/include/net/busy_poll.h, branch linux-5.11.y

net, xdp, xsk: fix __sk_mark_napi_id_once napi_id error

2020-12-01T14:51:19Z

Stephen reported the following build error for !CONFIG_NET_RX_BUSY_POLL built kernels: In file included from fs/select.c:32: include/net/busy_poll.h: In function 'sk_mark_napi_id_once': include/net/busy_poll.h:150:36: error: 'const struct sk_buff' has no member named 'napi_id' 150 | __sk_mark_napi_id_once_xdp(sk, skb->napi_id); | ^~ Fix it by wrapping a CONFIG_NET_RX_BUSY_POLL around the helpers. Fixes: b02e5a0ebb17 ("xsk: Propagate napi_id to XDP socket Rx path") Reported-by: Stephen Rothwell Signed-off-by: Stephen Rothwell Signed-off-by: Daniel Borkmann Cc: Björn Töpel Link: https://lore.kernel.org/linux-next/20201201190746.7d3357fb@canb.auug.org.au

xsk: Propagate napi_id to XDP socket Rx path

2020-11-30T23:09:25Z

Add napi_id to the xdp_rxq_info structure, and make sure the XDP socket pick up the napi_id in the Rx path. The napi_id is used to find the corresponding NAPI structure for socket busy polling. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Acked-by: Ilias Apalodimas Acked-by: Michael S. Tsirkin Acked-by: Tariq Toukan Link: https://lore.kernel.org/bpf/20201130185205.196029-7-bjorn.topel@gmail.com

net: Add SO_BUSY_POLL_BUDGET socket option

2020-11-30T23:09:25Z

This option lets a user set a per socket NAPI budget for busy-polling. If the options is not set, it will use the default of 8. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/20201130185205.196029-3-bjorn.topel@gmail.com

net: Introduce preferred busy-polling

2020-11-30T23:09:25Z

The existing busy-polling mode, enabled by the SO_BUSY_POLL socket option or system-wide using the /proc/sys/net/core/busy_read knob, is an opportunistic. That means that if the NAPI context is not scheduled, it will poll it. If, after busy-polling, the budget is exceeded the busy-polling logic will schedule the NAPI onto the regular softirq handling. One implication of the behavior above is that a busy/heavy loaded NAPI context will never enter/allow for busy-polling. Some applications prefer that most NAPI processing would be done by busy-polling. This series adds a new socket option, SO_PREFER_BUSY_POLL, that works in concert with the napi_defer_hard_irqs and gro_flush_timeout knobs. The napi_defer_hard_irqs and gro_flush_timeout knobs were introduced in commit 6f8b12d661d0 ("net: napi: add hard irqs deferral feature"), and allows for a user to defer interrupts to be enabled and instead schedule the NAPI context from a watchdog timer. When a user enables the SO_PREFER_BUSY_POLL, again with the other knobs enabled, and the NAPI context is being processed by a softirq, the softirq NAPI processing will exit early to allow the busy-polling to be performed. If the application stops performing busy-polling via a system call, the watchdog timer defined by gro_flush_timeout will timeout, and regular softirq handling will resume. In summary; Heavy traffic applications that prefer busy-polling over softirq processing should use this option. Example usage: $ echo 2 | sudo tee /sys/class/net/ens785f1/napi_defer_hard_irqs $ echo 200000 | sudo tee /sys/class/net/ens785f1/gro_flush_timeout Note that the timeout should be larger than the userspace processing window, otherwise the watchdog will timeout and fall back to regular softirq processing. Enable the SO_BUSY_POLL/SO_PREFER_BUSY_POLL options on your socket. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/20201130185205.196029-2-bjorn.topel@gmail.com

net: Avoid overwriting valid skb->napi_id

2020-06-21T00:30:59Z

This will be useful to allow busy poll for tunneled traffic. In case of busy poll for sessions over tunnels, the underlying physical device's queues need to be polled. Tunnels schedule NAPI either via netif_rx() for backlog queue or schedule the gro_cell_poll(). netif_rx() propagates the valid skb->napi_id to the socket. OTOH, gro_cell_poll() stamps the skb->napi_id again by calling skb_mark_napi_id() with the tunnel NAPI which is not a busy poll candidate. This was preventing tunneled traffic to use busy poll. A valid NAPI ID in the skb indicates it was already marked for busy poll by a NAPI driver and hence needs to be copied into the socket. Signed-off-by: Amritha Nambiar Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

net: annotate lockless accesses to sk->sk_napi_id

2019-10-31T00:34:35Z

We already annotated most accesses to sk->sk_napi_id We missed sk_mark_napi_id() and sk_mark_napi_id_once() which might be called without socket lock held in UDP stack. KCSAN reported : BUG: KCSAN: data-race in udpv6_queue_rcv_one_skb / udpv6_queue_rcv_one_skb write to 0xffff888121c6d108 of 4 bytes by interrupt on cpu 0: sk_mark_napi_id include/net/busy_poll.h:125 [inline] __udpv6_queue_rcv_skb net/ipv6/udp.c:571 [inline] udpv6_queue_rcv_one_skb+0x70c/0xb40 net/ipv6/udp.c:672 udpv6_queue_rcv_skb+0xb5/0x400 net/ipv6/udp.c:689 udp6_unicast_rcv_skb.isra.0+0xd7/0x180 net/ipv6/udp.c:832 __udp6_lib_rcv+0x69c/0x1770 net/ipv6/udp.c:913 udpv6_rcv+0x2b/0x40 net/ipv6/udp.c:1015 ip6_protocol_deliver_rcu+0x22a/0xbe0 net/ipv6/ip6_input.c:409 ip6_input_finish+0x30/0x50 net/ipv6/ip6_input.c:450 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip6_input+0x177/0x190 net/ipv6/ip6_input.c:459 dst_input include/net/dst.h:442 [inline] ip6_rcv_finish+0x110/0x140 net/ipv6/ip6_input.c:76 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ipv6_rcv+0x1a1/0x1b0 net/ipv6/ip6_input.c:284 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5010 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5124 process_backlog+0x1d3/0x420 net/core/dev.c:5955 napi_poll net/core/dev.c:6392 [inline] net_rx_action+0x3ae/0xa90 net/core/dev.c:6460 write to 0xffff888121c6d108 of 4 bytes by interrupt on cpu 1: sk_mark_napi_id include/net/busy_poll.h:125 [inline] __udpv6_queue_rcv_skb net/ipv6/udp.c:571 [inline] udpv6_queue_rcv_one_skb+0x70c/0xb40 net/ipv6/udp.c:672 udpv6_queue_rcv_skb+0xb5/0x400 net/ipv6/udp.c:689 udp6_unicast_rcv_skb.isra.0+0xd7/0x180 net/ipv6/udp.c:832 __udp6_lib_rcv+0x69c/0x1770 net/ipv6/udp.c:913 udpv6_rcv+0x2b/0x40 net/ipv6/udp.c:1015 ip6_protocol_deliver_rcu+0x22a/0xbe0 net/ipv6/ip6_input.c:409 ip6_input_finish+0x30/0x50 net/ipv6/ip6_input.c:450 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip6_input+0x177/0x190 net/ipv6/ip6_input.c:459 dst_input include/net/dst.h:442 [inline] ip6_rcv_finish+0x110/0x140 net/ipv6/ip6_input.c:76 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ipv6_rcv+0x1a1/0x1b0 net/ipv6/ip6_input.c:284 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5010 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5124 process_backlog+0x1d3/0x420 net/core/dev.c:5955 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 10890 Comm: syz-executor.0 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: e68b6e50fa35 ("udp: enable busy polling for all sockets") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335

2019-06-05T15:37:06Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin st fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 111 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000436.567572064@linutronix.de Signed-off-by: Greg Kroah-Hartman

net: remove sock_poll_busy_flag

2018-07-30T16:10:25Z

Fold it into the only caller to make the code simpler and easier to read. Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller

net: remove sock_poll_busy_loop

2018-07-30T16:10:25Z

There is no point in hiding this logic in a helper. Also remove the useless events != 0 check and only busy loop once we know we actually have a poll method. Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller

net: Record receive queue number for a connection

2018-07-02T00:06:24Z

This patch adds a new field to sock_common 'skc_rx_queue_mapping' which holds the receive queue number for the connection. The Rx queue is marked in tcp_finish_connect() to allow a client app to do SO_INCOMING_NAPI_ID after a connect() call to get the right queue association for a socket. Rx queue is also marked in tcp_conn_request() to allow syn-ack to go on the right tx-queue associated with the queue on which syn is received. Signed-off-by: Amritha Nambiar Signed-off-by: Sridhar Samudrala Signed-off-by: David S. Miller