openwrt/target/linux/generic/backport-4.9/024-2-tcp-tsq-remove-one-locked-operation-in-tcp_wfree.patch
Stijn Segers 9e1530b2a3 kernel: bump 4.9 to 4.9.117 for 18.06
* Refreshed patches.
* Removed patches:
  - target/linux/ar71xx/patches-4.9/103-MIPS-ath79-fix-register-address-in-ath79_ddr_wb_flus.patch superseded by upstream
  - target/linux/ar71xx/patches-4.9/403-mtd_fix_cfi_cmdset_0002_status_check.patch superseded by upstream
  - target/linux/brcm63xx/patches-4.9/001-4.11-01-mtd-m25p80-consider-max-message-size-in-m25p80_read.patch accepted upstream
  - target/linux/brcm63xx/patches-4.9/001-4.15-08-bcm63xx_enet-correct-clock-usage.patch accepted upstream
  - target/linux/brcm63xx/patches-4.9/001-4.15-09-bcm63xx_enet-do-not-write-to-random-DMA-channel-on-B.patch accepted upstream
  - target/linux/generic/pending-4.9/900-gen_stats-fix-netlink-stats-padding.patch

* New backported patch to address ext4 breakage, introduced in 4.9.112:
  - backport-4.9/500-ext4-fix-check-to-prevent-initializing-reserved-inod.patch

Also add ARM64_SSBD symbol to ARM64 targets still running kernel 4.9

Thanks to Koen Vandeputte for pointing out the need to add the ARM64_SSBD symbol, and the ext4 patch.

Compile-tested on: ar71xx
Run-tested on: ar71xx

Signed-off-by: Stijn Segers <foss@volatilesystems.org>
2018-08-06 07:30:32 +02:00

49 lines
1.6 KiB
Diff

From 408f0a6c21e124cc4f6c7aa370b38aa47e55428d Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Sat, 3 Dec 2016 11:14:51 -0800
Subject: [PATCH 02/10] tcp: tsq: remove one locked operation in tcp_wfree()
Instead of atomically clear TSQ_THROTTLED and atomically set TSQ_QUEUED
bits, use one cmpxchg() to perform a single locked operation.
Since the following patch will also set TCP_TSQ_DEFERRED here,
this cmpxchg() will make this addition free.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/tcp_output.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -865,6 +865,7 @@ void tcp_wfree(struct sk_buff *skb)
{
struct sock *sk = skb->sk;
struct tcp_sock *tp = tcp_sk(sk);
+ unsigned long flags, nval, oval;
int wmem;
/* Keep one reference on sk_wmem_alloc.
@@ -882,11 +883,17 @@ void tcp_wfree(struct sk_buff *skb)
if (wmem >= SKB_TRUESIZE(1) && this_cpu_ksoftirqd() == current)
goto out;
- if (test_and_clear_bit(TSQ_THROTTLED, &tp->tsq_flags) &&
- !test_and_set_bit(TSQ_QUEUED, &tp->tsq_flags)) {
- unsigned long flags;
+ for (oval = READ_ONCE(tp->tsq_flags);; oval = nval) {
struct tsq_tasklet *tsq;
+ if (!(oval & TSQF_THROTTLED) || (oval & TSQF_QUEUED))
+ goto out;
+
+ nval = (oval & ~TSQF_THROTTLED) | TSQF_QUEUED;
+ nval = cmpxchg(&tp->tsq_flags, oval, nval);
+ if (nval != oval)
+ continue;
+
/* queue this socket to tasklet queue */
local_irq_save(flags);
tsq = this_cpu_ptr(&tsq_tasklet);