From 7e417a66b86c110f4b282945dac82e21e0b08328 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 22 Apr 2020 09:13:28 -0700 Subject: [PATCH] net: napi: use READ_ONCE()/WRITE_ONCE() gro_flush_timeout and napi_defer_hard_irqs can be read from napi_complete_done() while other cpus write the value, whithout explicit synchronization. Use READ_ONCE()/WRITE_ONCE() to annotate the races. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 6 +++--- net/core/net-sysfs.c | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 6758548..afff168 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6242,12 +6242,12 @@ bool napi_complete_done(struct napi_struct *n, int work_done) if (work_done) { if (n->gro_bitmask) - timeout = n->dev->gro_flush_timeout; - n->defer_hard_irqs_count = n->dev->napi_defer_hard_irqs; + timeout = READ_ONCE(n->dev->gro_flush_timeout); + n->defer_hard_irqs_count = READ_ONCE(n->dev->napi_defer_hard_irqs); } if (n->defer_hard_irqs_count > 0) { n->defer_hard_irqs_count--; - timeout = n->dev->gro_flush_timeout; + timeout = READ_ONCE(n->dev->gro_flush_timeout); if (timeout) ret = false; } diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index f3b650c..880e89c 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -367,7 +367,7 @@ NETDEVICE_SHOW_RW(tx_queue_len, fmt_dec); static int change_gro_flush_timeout(struct net_device *dev, unsigned long val) { - dev->gro_flush_timeout = val; + WRITE_ONCE(dev->gro_flush_timeout, val); return 0; } @@ -384,7 +384,7 @@ NETDEVICE_SHOW_RW(gro_flush_timeout, fmt_ulong); static int change_napi_defer_hard_irqs(struct net_device *dev, unsigned long val) { - dev->napi_defer_hard_irqs = val; + WRITE_ONCE(dev->napi_defer_hard_irqs, val); return 0; } -- 2.7.4